Neutrino detection with semiconductor ionization detectors; application and usage of neutrino detectors

Abstract

A neutrino detection system and method based on one or more semiconductor Germanium point-contact diodes. These diodes act simultaneously as target for neutrinos or antineutrinos, that scatter off atomic nuclei, and as detectors, that register the ionization energy released in such interactions. Also included are various compact shield configurations that enhance the signal-to-background ratio and allow for a mobile detector operation under many environmental conditions including above ground and close to reactor sites. The neutrino detector can be used, for instance, for reactor operation monitoring, geological-radiochemical surveys and neutrino telecommunication systems.

Description

[0001] NEUTRINO DETECTION WITH SEMICONDUCTOR IONIZATION DETECTORS; APPLICATION AND USAGE OF NEUTRINO DETECTORS

[0002] TECHNICAL FIELD

[0003] The present disclosure generally pertains to a neutrino detection device, a vehicle, a neutrino detection method, a reactor monitoring method, a geological-radiochemical sensing method and a telecommunications method.

[0004] TECHNICAL BACKGROUND

[0005] Neutrinos (v) and antineutrinos (va), are produced in several nuclear processes occurring naturally or under artificial conditions. As such, they are carrier of rich information (energy, time) from the emission source and can therefore be used to study or monitor original nuclear processes. However, neutrinos and their antiparticles have very small masses and interact with matter only via the weak force. Therefore, they are in general very elusive. Research experiments of the last seven decades have demonstrated how challenging it is to detect neutrinos and their antiparticles. Normally, these projects have made use of hundreds of tons of target material, specialized detection systems, large onion-like shields against natural radioactivity and they have been located deep (a few 100s meters of water equivalent) or very deep (a few 1000s meters of water equivalent) underground to reduce the unwanted significant background contribution from cosmic radiation at Earth’s surface.

[0006] Out of theoretically six possible neutrino interaction channels, neutrino experiments have used so far mainly neutrino-electron scattering (NES), corresponding to v + e — v + q for the detection of neutrinos and the inverse beta decay (IBD), corresponding to va+ p — n + q for the exclusive detection of antineutrinos wherein p stands for proton, n for neutron and e+for the positively charged positron. Except for this restriction and an energy cut-off at 1.8 MeV (Mega electronvolts), the IBD reaction is advantageous, since the temporal and spatial coincidence of the prompt positron annihilation and the delayed neutron capture is very powerful in rejecting many types of background. This is still valid at Earth’s surface, which explains more recent developments, such as described in Patent Literature US 10,429,526 or Patent Literature US 10,436,919 on using IBD-based neutrino detectors for applications such as reactor monitoring of the thermal power, of the spent fuel activity and of the fission fraction evolution, the latter also in terms of near-field and far-field nonproliferation safeguards, such as described in Non-Patent Literature M. Askins et al., https: / / doi.org / 10.48550 / arXiv.1502.01132 or Non-Patent Literature T. Lasserre et al., https: / / doi.org / 10.48550 / arXiv.1011.3850. In this respect, the Novel Technologies Unit of the International Atomic Energy Agency prefers near-field units that are reliable, easy to operate, mobile and not cost intensive. A further promising neutrino interaction channel is elastic neutrino nucleus scattering (v+ A— v+ A) (NNS), in which a neutrino scatters off an atomic nucleus, herein denoted with A. Due to a quantummechanical coherency effect, the scattering process is enhanced by several orders of magnitude compared to the IBD and NES channels. For the first time, this would allow for the construction of small and mobile neutrino detectors.

[0007] NNS has first been theoretically predicted in the 1970s and is a robust prediction of the standard model of elementary particle physics.

[0008] In Patent Literature US 4,968,475, a compact superconducting neutrino detector has been detailed relying on the possibility to exploit the NNS channel, however without reaching very low energy thresholds. More recently another NNS-based neutrino detector system has been proposed in Patent Literature US 10,935,674. It consists of a CaWCL crystal (array) as target, in which neutrino interactions release phonons, an independent transition edge sensor, which detects the subsequent temperature increase in the crystals, and 2 real-time veto systems (inner and outer) based again on temperature sensors to reduce background events. The operation of the setup is demanding since it requires permanently ultra-low cryogenic temperatures below 200 milli-Kelvin (mK).

[0009] Neutrino detection based on semiconductor high purity germanium technology (HPGe) is known, for example, from the Non-Patent Literature H. Bonet et al., https: / / doi.org / 10.1140 / epjc / sl0052-021- 09038-3 and Non-Patent Literature G. Heusser et al., https: / / doi.org / 10.1140 / epjc / sl0052-015- 3704-2, using a large kg-sized, low-noise point-contact HPGe diode exhibiting very low energy detection thresholds better than 200 electronvolt (eV). Compared to the neutrino detector system in Patent Literature US 10,935,674, the HPGe diode offers a fast neutrino detector response allowing for a 100-fold larger trigger rate. Further, the HPGe diode is embedded in a cryostat system that is cooled down via a small electrical cryocooler unit to easily-reachable sufficient temperatures of about 60-100 Kelvin (K).

[0010] EP 3 848 943 Al is concerned with reactor monitoring of thermal power by means of a germanium detector which measures special gamma radiation. The special gamma radiation correlates in real time with the thermal power. A high measurement accuracy of the thermal power (3%) can be achieved in a short time (15 minutes). This corresponds to what is required for monitoring regular reactor operation.

[0011] The germanium detector in EP 3 848 943 Al is characterized by a particularly large diode, that can precisely determine the thermal power in a short time but cannot separate the time evolution of the relative rates of the fissile isotopes. However, it does not require a low low-energy detection threshold or shielding, as the characteristic gamma radiation of 6.1 MeV is easily recognizable in the spectrum and is higher-energy and higher-intensity compared to natural ambient radiation (<2.6 MeV) and needs to be located relatively close to the primary cooling circuit and as little material as possible should be located between the detector and the emitter, as the gamma radiation would be significantly attenuated by the stronger absorption caused by the material.

[0012] There is a need for a reactor monitoring device that can, at least partially, overcome the deficiencies of the state of the art.

[0013] SUMMARY

[0014] According to a first aspect, the present disclosure provides a neutrino detection device in accordance with independent claim 1. According to a second aspect, the present disclosure provides a vehicle in accordance with independent claim 26. According to a third aspect, the present disclosure provides a neutrino detection method in accordance with independent claim 27. According to a fourth aspect, the present disclosure provides a reactor monitoring method in accordance with independent claim 28. According to a fifth aspect, the present disclosure provides a geological-radiochemical sensing method in accordance with independent claim 30. According to a sixth aspect, the present disclosure provides a telecommunication method in accordance with independent claim 32.

[0015] Further aspects are set forth in the dependent claims, the drawings and the following description.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Embodiments are explained by way of example with respect to the accompanying drawings, in which:

[0018] Fig. 1 is a schematic illustration of a neutrino scattering event in a radiation detection unit; and

[0019] Fig. 2 is a symbolic visual representation of a plurality of an example event energy spectrum, example neutrino spectra and background spectra; and

[0020] Fig. 3A and Fig. 3B are symbolic representations of event energy spectra, including neutrino spectra, as could be measured by the device; and

[0021] Fig. 4A and Fig. 4B are explanatory illustrations of a total number of excess events; and

[0022] Fig. 5A to Fig. 5C are explanatory illustrations of a method to determine a neutrino event rate; and

[0023] Fig. 6A and Fig. 6B are explanatory illustrations of a method to detect or identify a neutrino emission source and neutrino emission source components using a gradient of the event energy spectrum; and

[0024] Fig. 7 is a block diagram illustrating generation of an event energy spectrum based on sensor signals and veto signals; and Fig. 8 is a block diagram illustrating the analysis of a sensor signal by recognizing a characteristic spectral shape of the NNS signal; and

[0025] Fig. 9 is a block diagram illustrating the analysis of a sensor signal to obtain a neutrino event number; and

[0026] Fig. 10 is a block diagram illustrating the analysis of a sensor signal to identify a neutrino emission source and neutrino emission source components; and

[0027] Fig. 11 is a block diagram illustrating the analysis of a sensor signal to detect and identify a neutrino emission source in a vicinity of a monitoring location; and

[0028] Fig. 12 is a schematic cross-sectional view of a neutrino detector according to the present disclosure housed in a cryostat device; and

[0029] Fig. 13 is a schematic cross-sectional view of a neutrino detector according to the present disclosure in a first embodiment comprising a single neutrino detection device including a multilayer radiation shield; and

[0030] Fig. 14 is a schematic cross-sectional view of a neutrino detector according to the present disclosure in a second embodiment comprising a plurality of neutrino detection devices including a multilayer radiation shield; and

[0031] Fig. 15 is a schematic illustration for a setup for monitoring of the nuclear fuel composition of a reactor using a neutrino detector provided in a vehicle; and

[0032] Fig. 16 is a schematic illustration of a method for reactor monitoring; and

[0033] Fig. 17 is a schematic illustration of a disposition of the neutrino detector for use in geological- radiochemical sensing; and

[0034] Fig. 18 is a schematic illustration of a method for geological-radiochemical sensing; and

[0035] Fig. 19 is a schematic illustration of a disposition of the neutrino detector for use in a neutrino-based telecommunication; and

[0036] Fig. 20 is a schematic illustration of a method for neutrino-based telecommunication.

[0037] DETAILED DESCRIPTION OF EMBODIMENTS

[0038] Before a detailed description of the embodiments under reference to Fig. 1 is given, general explanations are made.

[0039] Coherent elastic neutrino nucleus scattering (NNS) is a neutrino interaction predicted by the Standard Modell of Elementary Particle Physics, in which a neutrino scatters off an atomic nucleus. Due to a quantum-mechanical coherency effect, the scattering process scales proportionally to the squared number of neutrons in the nucleus of the target material and thus the neutrino interaction probability can be enhanced by three to four orders of magnitude compared to the IBD and NES channels. In addition, NNS works equally for both neutrinos as well as antineutrinos, and it has no energy cut-off. The challenge is, however, the ability to detect the tiny nuclear recoil energies released in such processes. The absence of adequate technologies with sufficiently low detection thresholds has largely impeded the measurement of neutrinos via the NNS channel so far. A very recent NNS detection in Non-Patent Literature D. Akimov et al., https: / / doi.org / 10.1126 / science.aao0990, was based on the usage of high energetic neutrinos (up to several 10 mega-electronvolt (MeV)) requiring less stringent detector thresholds of 1 kilo-electronvolt (keV) and above. Other neutrino sources of interest such as nuclear reactors or radioactive decays in the Earth crust produce less energetic neutrinos (below 10 MeV) and require therefore detectors with even lower detection thresholds. This has not been achieved so far.

[0040] Compared to other neutrino interaction channels currently in use in other detection methods and / or devices, such as neutrino-electron scattering (v + c — > v + e') and inverse beta decay (va+ p — n + e+), NNS interaction has an interaction cross section that is about three to four order s of magnitude larger. Thus, a neutrino detector using NNS can be expected to provide a correspondingly higher detection efficiency for the same target mass.

[0041] The here presented NNS-based detection setup includes methods that are able to detect any of the mentioned neutrino sources of interest and that are able to reduce the preexisting background level by at least three orders of magnitude and that can be optimized according to the environmental conditions. The background rejection methods include external shield layers made of high-density materials, neutron moderating and capturing materials, cosmic ray anticoincidence detectors as well as the examination of the HPGe diode pulse shape information for offline event-by-event background discrimination. The proposed tonne-sized neutrino detector has a demonstrated long-term stability, it is easy and safe to operate, compact enough to allow for a mobile operation and suitable for above ground applications.

[0042] A neutrino detection device comprises a radiation detection unit comprising a semiconductor diode configured to act as both target and sensor, and read-out electronics comprising a read-out electrode configured to sense free charges generated in the target, wherein the read-out electronics is configured to generate, based on the free charges, sensor signals; and a data acquisition unit configured to identify, based on the sensor signals, neutrino-nucleus -scattering events. In the following, the neutrino detection device may also be called a “neutrino detector” or simply “detector”. The target comprises target material, which is a semiconductor material with sufficiently high abundance of nucleons per nucleus and a low ionization threshold.

[0043] The read-out electrode is an electrode configured to generate an electric field in the target material and collect free charges present in the target material. The free charges may either be electrons or holes.

[0044] Since the semiconductor diode acts as both sensor and target, intrinsic noise of the detection device can be reduced. Specifically, disadvantages of providing a sensor that is distinct from the target, can be avoided.

[0045] The read-out device, which may be called read-out electronics. The read-out device comprises circuitry configured to read-out free charges collected by the read-out electrode. Free charges may be read-out by counting a number of elementary charges collected by the read-out electrode or by measuring a total charge collected by the read-out electrode. Based on the collected free charges, the read-out electronics generate a sensor signal. The sensor signal may, for example, be an electric voltage measured at the read-out electrode over time or an electric current measured at the read-out electrode over time. The voltage and / or current may be read out in a predetermined read-out window. The read-out window may be understood as a time-bin of the measurement at the read-out electrode.

[0046] Based on the read-out window, a trigger rate may be calculated or the detection window may be based on a desirable or reachable trigger rate.

[0047] The data acquisition unit is an electronic device or circuitry configured to acquire the sensor signal from the read-out electronics, analyze the sensor signal and output a neutrino detection signal.

[0048] The data acquisition unit may be a device that communicates with the read-out electronics. The data acquisition unit may be a processing unit configured to analyze the sensor signal. The data acquisition unit may be a computer, a computer processor or any other electronic data processing device.

[0049] The data acquisition unit may further be configured to further amplify the sensor signal. Specifically, the read-out electronics may be configured to provide a low-noise signal amplification. For example, the read-out electronics may comprise a pre-amplifier.

[0050] The neutrino detector according to the present disclosure is capable of suppressing background radiation by three to four orders of magnitude compared to the normal background radiation on Earth’s surface in the energy band of neutrino-nucleus scattering.

[0051] In some embodiments the semiconductor diode is configured such that interaction of an incident neutrino generates free charges in the target material. NNS is a type of neutrino interaction wherein a neutrino scatters off, without further reaction, an atomic nucleus. Unlike other weak interactions, no change in lepton flavor or charge occurs, leaving the reaction with the same particles after interaction as before.

[0052] That said, the same scattering reaction can feature with the same probability a neutrino instead of an antineutrino. The neutrino detector according to the present disclosure is sensitive to both neutrino and antineutrino interactions.

[0053] During the scattering interaction, the neutrino imparts a certain amount of its momentum on the nucleus in a recoil. This recoil energy is transferred to the target material, which is ionized, releasing free charges that can be utilized to detect the interaction event and thus the neutrino.

[0054] It should be noted that, for the purposes of the present disclosure, detection of the interaction of a neutrino with the target material is equivalent to detection of the neutrino-nucleus scattering event.

[0055] Due to a quantum-mechanical coherency effect, the scattering process scales proportionally to the number of neutrons in the nucleus of the target material squared. Due to the coherency effect, the neutrino interaction probability is enhanced by three to four orders of magnitude compared to IBD and NES.

[0056] Due to the inherently low interaction probability of neutrinos, this enhancement greatly increases the detection efficiency of the neutrino detector. Due to the increased efficiency of the neutrino detector, the amount of target material required to detect a given neutrino flux, a mass and size of the neutrino detector may be much smaller than in known neutrino detectors.

[0057] NNS, as mentioned, works for both neutrinos as well antineutrinos, and it has no energy cut-off.

[0058] The observable effect of NNS is the nuclear recoil energy requiring a neutrino detector with very low energy threshold, such as the neutrino detector of the present disclosure.

[0059] Detecting the nuclear recoil energy is accomplished by providing a radiation detection unit such that, if an incident neutrino interacts with a nucleus of the target material, electrons of the electron cloud associated with the crystal lattice structure around the struck nucleus are ionized. By ionizing the electrons, electron-hole pairs are created. The free electrons are attracted, via an electric potential generated, for example, by applying an external bias voltage to the positively charged electrode, while the holes are attracted by the same potential to the negatively charge electrode.

[0060] Either the positively charged electrode or the negatively charged electrode can be used as read-out electrode for generating the sensor signals. According to an embodiment of the present invention, the target material is configured such, that the applied bias voltage is positive, and the read-out electrode reads out a sensor signal generated by the holes.

[0061] Either the electron or the hole can be understood to be a free charge within the meaning of the present disclosure.

[0062] Further interaction of the free charge, generated by the interaction of the neutrino with the nucleus, with further nuclei can generate additional free charges which are associated with the neutrino interaction.

[0063] There are embodiments wherein, if neutrino events are recognized, presence of a neutrino emission source is recognized.

[0064] In some embodiments data acquisition unit is configured to determine an event energy spectrum based on the sensor signals, and to determine neutrino-nucleus-scattering events based on the event energy spectrum.

[0065] A plurality of sensor signals are used to generate the event energy spectrum. The event energy spectrum describes a number of events in relation to the energy of the events. As such, the event energy spectrum correlates a number of events N(E) with an energy E of the events.

[0066] The plurality of sensor signals are obtained during a measurement period. The measurement period is a time period that is long enough to acquire a significant number of sensor signals from a neutrino flux. For example, the measurement period may be a few minutes, a few hours, a few days or longer. Measuring sensor signals for a measurement period may be called a measurement procedure.

[0067] The event-energy spectrum may be a binned spectrum, wherein the energy E is separated into a series of bins of a predetermined width. The number of the events N(E) may correspond to the value of the bin of energy E.

[0068] The event energy of each event is calculated based on the signal voltage and / or the signal current of the corresponding sensor signal using known methodologies. The known methodologies may include integrating the signal voltage over the read-out window or multiplying a maximum signal voltage detected in the read-out window with the maximum signal current detected in the read-out window multiplied by the length of the read-out window. However, any method that will produce an event energy based on the signal voltage and / or the signal current may be used.

[0069] It should be noted that the event-energy spectrum comprises neutrino-nucleus scattering events as well as events that were not caused by neutrino-nucleus scattering. The event-energy spectrum is analyzed in order to detect and / or identify neutrino-nucleus scattering events in the event-energy spectrum.

[0070] By generating the event-energy spectrum and analyzing the event-energy spectrum, the neutrino scattering event may be detected and / or identified with accuracy.

[0071] In some embodiments the data acquisition unit is configured to identify the neutrino-nucleus - scattering events based on an increase of the event energy spectrum.

[0072] As described hereinabove, the event-energy spectrum comprises events that are due to neutrinonucleus scattering and events that are due to background events and / or other events that are not caused by neutrino-nucleus scattering. The background rate may be assumed to be constant with respect to time. If an increase over the nominal expected rate value of the event-energy spectrum in the energy region of neutrino-nucleus scattering events is detected, this indicates that the component due to neutrino-nucleus scattering is increasing.

[0073] The event-energy spectrum may be integrated to obtain an integrated value and an increase of the integrated value may indicate an increase of the event-energy spectrum identifying the neutrinonucleus scattering events.

[0074] In some embodiments the data acquisition unit is configured to identify the neutrino-nucleus - scattering events based on an increase of the event energy spectrum as compared to a predefined nominal event energy spectrum.

[0075] The nominal event energy spectrum may be a background spectrum. The background spectrum may be represented as a background event energy spectrum. The background spectrum may also be represented as a background spectral flux SCB. The background spectral flux may be obtained by measuring a number of background events NCB as a background event energy spectrum during a background measurement procedure in a predetermined background measurement time and dividing the background event energy spectrum by the predetermined background measurement time to obtain the background spectral flux. The background measurement may be a background calibration or a calibration.

[0076] The nominal event energy spectrum may for example result from background events produced in the detector by cosmic rays, radiation from natural radioactivity in the environment, detector noise, radiation, or the like.

[0077] The increase of the event energy spectrum may be detected by comparing a value in a bin in the eventenergy spectrum with a value in a bin of the same energy and normalized to the same data collection time in the nominal event energy spectrum and determining whether the value in the bin of the event energy spectrum is larger than the value in the bin of the nominal event energy spectrum.

[0078] The comparing may be performed on a bin-by-bin basis for all energies of the event-energy spectrum or for parts of the event-energy spectrum.

[0079] The increase of the event energy spectrum as compared to a nominal event energy spectrum within the same detection frame may, for example, be detected if the values of a majority of the compared bins of the event energy spectrum are larger than the values of the corresponding bins of the nominal event energy spectrum.

[0080] Again alternatively, the increase of the event energy spectrum may be detected by subtracting the nominal event energy spectrum normalized to the same data collection time from the event energy spectrum and then determining of the remaining event energy spectrum comprises a minimum number of bins with values significantly larger than zero.

[0081] In some embodiments, the nominal event energy spectrum is a prestored spectrum that has been determined in a background measurement process conducted in absence of a neutrino source in a vicinity of the detector.

[0082] The nominal event energy spectrum may be prestored by being encoded and electronically stored on a data storage device that may, for example, be comprised by the data acquisition unit or by another electronic device connected to the data acquisition unit.

[0083] The background measurement process may be performed in a background measurement process by acquiring an event energy spectrum as described hereinabove, a measurement procedure and then storing the resulting event energy spectrum as the predetermined nominal event energy spectrum.

[0084] The nominal event energy spectrum may, according to an embodiment, determined in a vicinity of a measurement location.

[0085] The nominal event energy spectrum may, according to another embodiment, determined with the detector located in a location with a low expected neutrino flux (e.g. in a mine for non-radioactive ores and / or minerals or submerged underwater at significant depths).

[0086] In some embodiments, the data acquisition unit is configured to determine the neutrino-nucleus- scattering events based on the event energy spectrum at energies that are indicative of neutrino- nucleus-scattering events.

[0087] The data acquisition unit may for example be configured to determine the neutrino-nucleus-scattering events within one or more predetermined energy bands that are indicative of neutrino-nucleus- scattering events. Determining neutrino-nucleus-scattering events based on the event energy spectrum may for example comprise integrating parts of the event energy spectrum that are characteristic for neutrino-nucleus- scattering events.

[0088] In some embodiments, energies that are indicative of neutrino-nucleus-scattering events are energies of 1 keV or less, depending on the measured neutrino source and components of the neutrino source.

[0089] In some embodiments, a low energy detection threshold of less than 200 eV is achieved by comprising a very low noise radiation detection unit and a very low noise read-out electronics; and by a data acquisition system able to reconstruct sensor signal energies lower than 200 eV.

[0090] In some embodiments, identifying the neutrino-nucleus-scattering events comprises determining a shape and a gradient of the event energy spectrum.

[0091] A plurality of neutrino-nucleus scattering events will generate a characteristic shape in the event energy spectrum that differs from a plurality of events that are not caused by neutrino-nucleus scattering (background events). Neutrino-nucleus scattering events thus constitute a component of the eventenergy spectrum and background events constitute another component of the event-energy spectrum. Background events may be caused by interaction of particles that are not neutrinos with the target material or by other disturbances, such as concussions of the detector, mechanical vibrations, or the like.

[0092] In some embodiments, identifying the neutrino-nucleus-scattering events comprises determining an integrated count rate of the event energy spectrum.

[0093] The gradient may only be computed in an energy band with energies indicative of neutrino scattering events. For example, an energy band may have an upper energy limit of 260 eV and a lower limit of 80 eV or an upper limit of 360 eV and a lower limit of 80 eV.

[0094] The resulting gradient is then compared with a predetermined comparison value indicative of neutrino scattering. If the gradient matches the predetermined comparison value, the component of the spectrum wherein the gradient of the spectrum matches the predetermined comparison value is identified as being formed by neutrino scattering events. Thus, neutrino scattering events are identified.

[0095] The gradient of the event energy spectrum is, for example, a derivative of the energy number density N(E) with respect to the Energy E, i.e. dN(E) / dE. The gradient may, numerically, be computed, for a bin with index i at the energy E, as a difference equation using Here, N(E)^ is the number density Ntin the ith bin, E is the energy of the ith bin and so on.

[0096] However, other numerical methods for obtaining the gradient are possible, such as applying a linear regression algorithm within the energy band.

[0097] Before comparison with the comparison value, the gradient may be averaged, resulting in an average gradient using, for example:

[0098] Where pppp is the averaged gradient and k is another representation for the bin index. Indices in the above equation are to be interpreted conventionally. Further, i„„ may be a bin at a lower end of an energy band with energies indicative of neutrino scattering events, imaxmay be a bin at an upper end of an energy band with energies indicative of neutrino scattering events.

[0099] Note that, instead of a linear regression or a linear fit, nonlinear fits may be applied.

[0100] The comparison value may be called C.

[0101] Note that, as the neutrino component of the spectrum is expected to be decreasing, the comparison value C is, in the present embodiment, negative. The comparison may be accomplished by calculating whether the averaged gradient fulfils the following equation, such that, if fulfilled, the averaged gradient is recognized to match the comparison value C:

[0102] Here denotes a multiplication. The factor W is a predetermined adjustment parameter that may be chosen such that a gradient with small variations is still recognized as matching. W can be chosen at any value, including zero, but may, for example have a value of 0.05, such that a difference of 5% between the averaged gradient and the comparison value will still result in the averaged gradient being recognized as matching the comparison value.

[0103] In some embodiments, the data acquisition system is further configured to recognize, based on the event energy spectrum, a neutrino emission source and neutrino emission source components.

[0104] The neutrino emission source may for example be a fissile element emitting neutrinos in a decay process. The fissile / radioactive material may also be a material emitting neutrinos in a fission process.

[0105] The neutrino emission source may also be any other radioactive element that, as part of a nuclear decay process, emits neutrinos. Different neutrino emission sources, due to the underlying physics, lead to different shapes in the event energy spectrum. Each shape is characteristic of the neutrino emission source. By recognizing the characteristic shape, the neutrino emission source may be recognized.

[0106] The neutrino emission source may be a nuclear reactor or a geological source. Neutrinos emitted by a nuclear reactor as the neutrino emission source may be called “reactor neutrinos” and neutrinos emitted by a geological source may be called “geo-neutrinos”. Thus, a nuclear reactor may be recognized as the neutrino emission source by identifying, in the event-energy spectrum, a characteristic spectral shape corresponding to reactor neutrinos and the like.

[0107] Each neutrino emission source may be composed of a plurality of neutrino source components.

[0108] A neutrino source component is a type of fissile or radioactive material. In the case of reactorneutrinos, for instance, a neutrino source component might be attributed to a certain fissile / radioactive material.

[0109] Moreover, a neutrino emission source may also be any radioactive material that emits neutrinos but is not fissile. In the following, any method applied to fissile / radioactive material may also be understood to be applicable to radioactive material that is not fissile.

[0110] Specific neutrino source components are usually associated with a specific neutrino emission source. For example, uranium 235, which may be a neutrino source component, is associated with a nuclear reactor. Other neutrino emission source components associated with a nuclear reactor as the neutrino emission source are uranium 238, plutonium 239, plutonium 241 and others.

[0111] Some neutrino emission source components may be associated with more than one neutrino emission source.

[0112] Neutrino emission source components associated with a geological source are uranium 238, thorium 232, potassium 40 and others.

[0113] A neutrino emission source may be recognized by recognizing neutrino emission source components associated with the neutrino emission source. A neutrino emission source may also be recognized by recognizing a relative abundance of neutrino emission source components.

[0114] Each shape is therefore also characteristic of the neutrino emission source and the associated neutrino emission source components. By recognizing the characteristic shapes, the neutrino emission source and the associated neutrino emission source components may be recognized and differentiated.

[0115] Recognizing a neutrino emission source may be called identifying a neutrino emission source. In some embodiments, the neutrino emission source is recognized based on the shape or gradient of the event energy spectrum, or based on the integral count rate of the event energy spectrum.

[0116] The shape of the event energy spectrum may be recognized using shape recognition software.

[0117] Alternatively, the neutrino emission source may be recognized based on the gradient of the energy spectrum by comparison with the comparison value C.

[0118] Different values of the comparison value C are, due to underlying physics, associated with different neutrino emission sources and neutrino emission source components.

[0119] For example, a first value AC of the averaged gradient is expected if the neutrino emission source component is a first fissile / radioactive material.

[0120] By recognizing that the averaged gradient matches the comparison value C=AC, the first fissile / radioactive material can be recognized as the neutrino emission source component.

[0121] A second value BC of the averaged gradient is expected if the neutrino emission source component is a second fissile / radioactive material.

[0122] By recognizing that the averaged gradient matches the comparison value C=BC, the second fissile / radioactive material can be recognized as the neutrino emission source.

[0123] More generally, different comparison values C may be used to recognize different neutrino emission source components, such as shown in the following table:

[0124] There may be more or less than two comparison values that may be used to identify more or less than two fissile / radioactive materials.

[0125] The first fissile / radioactive material may, for example, be the uranium isotope U-235 and the second fissile / radioactive material may, for example, be the plutonium isotopes Pu-239 or Pu-241 or any of the neutrino emission source components mentioned hereinabove.

[0126] In some embodiments, the semiconductor diode is configured as a p-n junction and operated with a reverse bias voltage. The semiconductor diode comprises target material, which, to form the diode, is surrounded by an outer region. The target material, as described hereinabove, is a semiconductor material. The outer edge may be constituted from the same material.

[0127] The target material may be doped such that either a p-type semiconductor or an n-type semiconductor is obtained.

[0128] The outer region of the semiconductor diode may be composed of the same semiconductor as the target material, but the outer region may be doped such that a p-type semiconductor is provided if the target material is an n-type semiconductor and vice versa.

[0129] A polarity of the read-out electrode may be chosen such that the semiconductor diode is operated under a reverse-bias voltage. In this way, collection of the free charges by the read-out electrode can be optimized.

[0130] In some embodiments, the semiconductor diode is a semiconductor high-purity (HP) germanium diode or a semiconductor germanium point-contact diode.

[0131] Semiconductor high-purity germanium diode is a diode wherein the target material is a high-purity germanium material. Note that the germanium material may still be doped to obtain a p-type semiconductor or an n-type semiconductor.

[0132] By providing a semiconductor high-purity germanium diode, the detection efficiency can be further improved.

[0133] In some embodiments, the semiconductor diode is a semiconductor high-purity germanium diode and the read-out electronics is a very low noise read-out electronics and the read-out electrode is a pointlike read-out electrode.

[0134] A semiconductor germanium point-contact diode is a diode wherein the read-out electrode covers a small area of the surface of the target material, such as 1 mm2, or less. The read-out electrode may, in particular, cover a circular area with a radius of 1 mm, or less. Using a semiconductor germanium point-contact diode allows suppressing electronic noise generated by the diode itself. Furthermore, this improves the energy resolution of the neutrino detector and lowers the energy detection threshold.

[0135] In this way, the semiconductor diode and the read-out electronics are configured to obtain an energy threshold lower than 200 eV and a trigger efficiency close to 100% at the same energy.

[0136] With an energy threshold lower than 200 eV and a trigger efficiency close to 100%, detection of neutrino scattering detection of neutrinos from most known neutrino sources via NNS becomes possible. The semiconductor diode may further be provided in a cylindrical shape or a cylindrical shape with a bore hole on the opposite side of the read-out electrode. By providing the semiconductor diode in a cylindrical shape or a cylindrical shape with a bore hole on the opposite side of the read-out electrode electronic noise generated by the diode, the read-out electrode and the read-out electronics can be minimized. Furthermore, an energy resolution of the neutrino detector can be further improved, and the energy threshold of the neutrino detector can be lowered further.

[0137] Semiconductor high purity germanium diodes according to the present disclosure may be kg-sized, low-noise point-contact germanium diodes exhibiting very low energy thresholds better than 200 eV.

[0138] Semiconductor diodes according to the present disclosure thus offer a fast neutrino detector response allowing for a 100-fold larger trigger rate than in Patent Literature US 10,935,674.

[0139] Some embodiments further comprise a cryocooling device, configured to perform cryocooling of the device.

[0140] By providing cryocooling of the device, signal noise can be reduced.

[0141] In some embodiments, the radiation detection unit is operated at a temperature of less than 100 K. The cryocooling device may be any available cryocooling device capable of providing cooling to a temperature range between 60 and 100 K. For example, a nitrogen-based cryocooling device, or a dewar may be used, wherein periodically liquid nitrogen obtained from an outside source is provided.

[0142] The neutrino detector according to the present disclosure, unlike some known neutrino detectors, does not require cooling to extremely low temperatures, such as 10-100 mK, for example, as required by the neutrino detector discussed in Patent Literature US 10,935,674.

[0143] Since only cryocooling to a range between 60 and 100 K is required, the cryocooling device of the neutrino detector is simple in construction, requires minimal maintenance and can be small enough in size and mass to be mobile.

[0144] The cryocooling device may comprise an antivibration system, which suppresses vibrations from the cryocooling device itself and from the environment.

[0145] By suppressing vibrations from reaching the semiconductor diode, mechanically induced noise can be minimized, thereby further lowering the energy detection threshold of the neutrino detector.

[0146] Semiconductor diodes according to the present disclosure are housed in cryostats that are cooled via small electrical cryocooler units down to easily-reachable sufficient temperatures of about 60-100 K.

[0147] In some embodiments, the cryocooling device comprises a cryogenic temperature generator; and a cryostat system; wherein the cryostat system connects the radiation detection unit to the cryogenic temperature generator, such that the cryogenic temperature generator can be used to perform cooling of the radiation detection unit.

[0148] By providing cryocooling, thermally induced noise and electrical resistance in the semiconductor diode can be minimized, thereby further increasing the detection efficiency of the neutrino detector.

[0149] Some embodiments comprise a multilayer radiation shield that shields the radiation detection unit against background radiation, wherein the radiation detection unit is housed in the multilayer radiation shield.

[0150] The purpose of the multilayer radiation shield is to shield the semiconductor diode from externally generated radiation that may produce sensor signals that are not associated with neutrino interactions. By reducing the number of particles that are not neutrinos entering the semiconductor diode, a ratio between detected neutrino signals and background signals can be increased. Furthermore, this improves the possibility to disentangle the spectral shape contribution from NNS signals from the overall energy spectrum consisting of NNS, background and noise spectra.

[0151] In some embodiments, the multilayer radiation shield comprises one or more high-density material layers, wherein the high-density material layer comprises a high-density material, the high-density material further having a low amount of intrinsic self-radiation.

[0152] Ionizing radiation is absorbed by high-density material. By providing a high-density material layer surrounding the semiconductor diode, a flux of ionizing radiation reaching the semiconductor diode can be reduced.

[0153] The flux of ionizing background radiation can be reduced in order to prevent generation of free charges in the target material due to interaction of the ionizing background radiation with the target material. This decreases the background and signal noise in the neutrino detector.

[0154] There are embodiments wherein the high-density material layer comprises a layer of a thickness of at least 15 cm and consists of lead; or comprises a layer of high-density material that provides electromagnetic radiation shielding properties corresponding to a layer of a thickness of 15 cm that consists of lead.

[0155] As lead is a dense material, large amounts of it are heavy, thus increasing the mass of the neutrino detector. Thus, the amount of lead used should be as low as possible. By providing a high-density material layer of a thickness of at least 15 cm of lead, or equivalent material, the flux of ionizing radiation can be reduced sufficiently, while keeping the mass of the neutrino detector minimal.

[0156] The lead used may be of a high purity. Furthermore, the lead used may exhibit a low intrinsic radioactivity. In some embodiments, the multilayer radiation shield comprises one or more low-density material layers, wherein the low-density material layer comprises a low-density material, the low-density material further having material properties providing a high neutron moderation capability and a subsequent high neutron capture capability.

[0157] In some embodiments, the low-density material is a mixture of materials.

[0158] The material should be capable of both moderate and capture neutrons. If neutrons penetrate into the detector material (e.g. to the germanium crystals), unwanted background signals may be induced.

[0159] Neutrons are absorbed after being slowed down, thermalized and captured by a hydrogen-rich material loaded with, for example, boron or gadolinium. By providing such a hydrogen-rich material loaded with boron or gadolinium, the flux of neutrons reaching the semiconductor diode can be largely reduced.

[0160] The flux of neutrons can be reduced in order to prevent generation of free charges in the target material due to elastic or inelastic interaction of the neutrons with the target material. This decreases the background and signal noise in the neutrino detector.

[0161] By combining low-density and high-density layers in this manner, a flux of both ionizing radiation and neutrons can be minimized.

[0162] In some embodiments, the low-density material layer is at least 10 cm thick and consists of a material with material properties providing a high neutron capture probability.

[0163] The low-density material may be hydrogen-rich. By providing a low-density material layer of a thickness of at least 10 cm of hydrogen-rich material, doped, for example, with boron or gadolinium, the flux of ionizing radiation can be reduced sufficiently, while keeping the mass of the neutrino detector minimal.

[0164] In some embodiments, the multilayer radiation shield comprises an airborne radiation shield system, which suppresses airborne radiation penetrating the multilayer radiation shield by providing, in an interior of the multilayer radiation shield, an atmosphere with low intrinsic radioactivity.

[0165] The purpose of the airborne radiation shield system is to provide an atmosphere exhibiting low intrinsic radioactivity surrounding the semiconductor diode, additionally lowering the background radiation the semiconductor diode is exposed to. The airborne radiation shield may specifically be configured to provide radon-free air or radon-free nitrogen atmosphere.

[0166] By providing an atmosphere exhibiting low intrinsic radioactivity surrounding the semiconductor diode, airborne radiation present in the environment is suppressed. This way, an intrinsic radioactivity below 1 radon decay / sec / m3can be achieved. In some embodiments, the multilayer radiation shield comprises an anticoincidence veto system configured to detect incident cosmic radiation, and to generate a veto signal with a predetermined veto interval following a detection of incident ionizing radiation, and to transmit the veto signal to the data acquisition system.

[0167] A veto signal is provided by the anticoincidence veto system configured to detect ionizing radiation that should not be detected. The anticoincidence veto detector may be based on any of a number of suitable known technologies, such as a multiwire proportional counter detector. However, the anticoincidence veto detector may, in particular, be a liquid or plastic scintillation detector. In a scintillation detector, in response to ionizing background radiation incident on the detector volume, scintillation light is induced and sensed by a scintillation light detection device.

[0168] The scintillation light detection devices may specifically comprise a photo multiplayer tube system or a silicon photomultiplier system.

[0169] The anticoincidence veto detector can provide the veto signal.

[0170] The anticoincidence veto detector may be provided with its own control unit or use the control unit or data acquisition unit of the neutrino detector. The anticoincidence veto detector is configured to generate a veto signal if a cosmic radiation particle is detected. The veto signal is then used in the analysis of the sensor signal.

[0171] The anticoincidence veto detector may be provided as a plastic scintillator plate of a thickness of at least 5 cm.

[0172] In some embodiments, the data acquisition system is further configured to reject, based on reception of the veto signal, sensor signals during the veto interval. The veto interval may be predetermined.

[0173] The veto signal indicates that the veto system has detected a particle that is not a neutrino but would lead to a sensor signal being generated, such as cosmic radiation, and has a certain veto interval. Any sensor signal detected within a veto interval will be rejected by the data acquisition unit.

[0174] The incident ionizing radiation may originate from cosmic radiation.

[0175] Cosmic radiation may be detected using, for example, the plastic scintillator, as described hereinabove. The plastic scintillator may be configured to detect cosmic radiation on a basis of the very high energy deposition of incident muons. Gamma radiation from natural radioactive decays of ambient radiation, for example, reaches a maximum of 3 MeV energy. Cosmic muons, on the other hand, can leave several 10 MeV energy deposition in the plastic scintillator.

[0176] Cosmic muons may be distinguished in the following way: Photosensors such as photomultiplier tubes comprised by the scintillation detector in the anticoincidence system deliver signals with different amplitudes and a spectral distribution consisting of two components is obtained:

[0177] - a distribution that extends up to approximately 3 MeV; and

[0178] - a distribution that ranges from 0 to several 10 MeV.

[0179] A threshold is then defined which mainly admits only events above approximately 3 MeV to be registered. These events correspond almost exclusively to cosmic muons and are used to induce veto signals in the data acquisition system.

[0180] Due to the threshold definition, muons with energy depositions below 3 MeV are not taken into account, but the resulting inefficiency is small (in the range of 1 percent).

[0181] It should be added that different types of anticoincidence systems may be used in the neutrino detector.

[0182] For example, the anticoincidence system may comprise a multiwire proportional counter or the plastic scintillator, as described hereinabove.

[0183] Each of the different types may require a specific threshold: For example, multiwire proportional counters have a poorer energy resolution and therefore the distinction of gamma rays and cosmic muon radiation is less efficient, but the system is inexpensive.

[0184] On the other hand, plastic scintillators allow better separation, but are also more expensive.

[0185] Some embodiments comprise a plurality of the radiation detection units; and a plurality of the readout electronics; and one or more of the data acquisition systems, wherein one each of the data acquisition system analyzes the sensor signals from at least one of the radiation detection units; a plurality of cryocooling devices, wherein each one of the radiation detection units is housed in one each of the cryostat systems; and one multilayer radiation shield surrounding the cryostat systems.

[0186] By providing a plurality of cryostats, each housing a single semiconductor diode and read-out electronics, the amount of target material in the neutrino detector can be increased, thereby increasing the sensitivity of the neutrino detector. Furthermore, the neutrino detector may only use a single multilayer radiation shield and a single data acquisition unit, thereby reducing the amount of shielding required per semiconductor diode.

[0187] According to some embodiments, the present disclosure provides a vehicle, comprising the neutrino detector. The neutrino detector according to the present disclosure is small and light enough to be mounted on a vehicle. The vehicle may be a road vehicle, such as a truck. The vehicle may be a train. The vehicle may be a watercraft, such as a ship. The vehicle may be an aircraft or a spacecraft.

[0188] A neutrino detection method according to the present disclosure comprises sensing free charges generated in a target, generating, based on the sensed free charges, a sensor signal, and identifying, based on a plurality of the sensor signals, a neutrino-nucleus-scattering event.

[0189] This method is executed by the detector according to the present disclosure.

[0190] A reactor monitoring method according to the present disclosure comprises measuring with the device according to the present disclosure, located at a detector position, a plurality of neutrino- nucleus-scattering events during a monitoring period and recognizes, based on the neutrino-nucleus- scattering events, a neutrino emission source.

[0191] By recognizing the neutrino emission source, ongoing nuclear reactions in the reactor may be detected. Furthermore, by recognizing the neutrino emission source as fissile / radioactive material, a fissile / radioactive material used in the reactor may be recognized. Furthermore, a reactor neutrino emission source and its components and thus changes in the reactor fuel composition in a given reactor may be recognized. The fuel composition is indicated by the relative abundance of neutrino emission source components. The reactor may also be a type of nuclear facility that contains fissile / radioactive material but that is not a reactor. For example, the method according to the present disclosure may be used to monitor a nuclear enrichment facility, a particle accelerator, a nuclear research facility, a nuclear fuel storage facility and the like.

[0192] Neutrinos exhibit a very low interaction cross section and are difficult to shield. Therefore, the neutrino detector may be placed anywhere in the vicinity of the nuclear reactor to be monitored, such as inside or outside a reactor housing, inside or outside a reactor building on the premises of a nuclear power station. By providing a neutrino detector with a higher neutrino detector mass, such as in an alternative embodiment of the present technology, the neutrino detector may be placed at a considerable distance from the nuclear reactor to be monitored.

[0193] The nuclear reactor may, for example, be a boiling water reactor, a pressurized water reactor, an advanced gas-cooled reactor, a light water graphite-moderated reactor or a fast neutron reactor.

[0194] It should be noted that the reactor monitoring method according to the present disclosure does not require an empirical background measurement of the measured neutrino rates into absolute neutrino fluxes, since relative statements about the variation of the nuclear fuel composition can already be made by monitoring the neutrino rates alone. For example, if the detected neutrino rates related to a certain fissile / radioactive material or fission product, as the neutrino emission source, halves, one may conclude that the amount of the corresponding fissile / radioactive material or fission product in the reactor was reduced by factor of two.

[0195] Some embodiments of the reactor monitoring method further comprise monitoring a change of the neutrino emission source; wherein the monitoring comprises recognizing a change in parts of the event energy spectrum that are characteristic for neutrino-nucleus-scattering events.

[0196] Change is a change with respect to time.

[0197] A change in the parts of the event energy spectrum that are characteristic for neutrino-nucleus- scattering events may be recognized by recognizing a change of an averaged gradient of the event energy spectrum. For example, at a first time the averaged gradient may match a first comparison value and at a second time, the averaged gradient may match a second comparison value. Such a change may indicate a change in the operation of the reactor.

[0198] Such a change may indicate a change in fissile / radioactive material produced in the reactor. For example, a composition of nuclear fuel rods of the reactor may be recognized.

[0199] Further, by placing the neutrino detector in a vicinity of a nuclear reactor, neutrinos emitted by the nuclear reactor, a rate of fission reaction in the reactor, emitting neutrinos, can be determined.

[0200] It is mentioned that the reactor monitoring method may also employ a plurality of neutrino detectors, which may improve accuracy and / or reduce the need for a background measurement.

[0201] A geological-radiochemical sensing method according to the present disclosure comprises: position a neutrino detection device at a first position and measure a first neutrino-nucleus-scattering event rate; position the neutrino detection device at a second position and measure a second neutrino- nucleus-scattering event rate; and triangulate, based on the first neutrino-nucleus-scattering event rate and the second neutrino-nucleus-scattering event rate, a position of a neutrino emitter; wherein the neutrino detection device is the neutrino detection device according to the present disclosure.

[0202] The position of a neutrino source, such as ores rich of fissile / radioactive material, may be located using triangulation. By measuring a rate of neutrino detection at a plurality of positions, the source position may be calculated.

[0203] A particle flux is known to decrease in an inverse correlation with a square of the distance from the source of the particle flux. Therefore, by knowing the magnitude of the particle flux at a plurality of positions, the position of the source with respect to the plurality of positions can be calculated. A telecommunication method according to the present disclosure comprises generating a neutrino transmission using a controlled neutrino source; and detecting the neutrino transmission using the neutrino detection device according to the present disclosure.

[0204] The information may, for example, be a text message, data, a video message or any other type of information that can be encoded in a modulated signal. The information may be encoded in a known information encoding standard.

[0205] A modulated neutrino signal is generated based on the modulated signal using a controlled neutrino source. The controlled neutrino source may, for example, be a particle accelerator.

[0206] This way, information may be transmitted using neutrinos. Using neutrinos, messages may be transmitted through solids or liquids without requirement of line-of sight.

[0207] The information may even be transmitted through the Earth’s interior wherein the artificial neutrino generator may lie on the opposite side of the Earth compared to the neutrino detection device.

[0208] The methods as described herein are also implemented in some embodiments as a computer program causing a computer and / or a processor to perform the method, when being carried out on the computer and / or processor. In some embodiments, also a non-transitory computer-readable recording medium is provided that stores therein a computer program product, which, when executed by a processor, such as the processor described above, causes the methods described herein to be performed.

[0209] The neutrino detector according to the present disclosure provides for a reduction of the background level by at least three orders of magnitude and can be adopted according to the environmental conditions. The background rejection methods include external shield layers made of high-density materials, neutron moderating and capturing materials, cosmic ray anticoincidence detectors as well as examination of the sensor signal for offline event-by- event background discrimination.

[0210] The neutrino detector may be tonne-sized and has a long-term stability. Long-term stability is ensured by the utilized target material, for example Ge, exhibiting long-term chemical and structural stability down to atomic level. The neutrino detector according to the present disclosure is easy and safe to operate, compact enough to allow for a mobile operation and suitable for above ground applications.

[0211] Returning to the illustrations, embodiments of the present disclosure are described in detail.

[0212] Fig. 1 is a schematic illustration of a neutrino scattering event in a radiation detection unit 101. The radiation detection unit 101 comprises a semiconductor diode 100 and read-out electronics 133. The read-out electronics comprise a read-out electrode 131. The semiconductor diode 100 comprises target material 132. The semiconductor diode is operated in a reverse-bias voltage. An incident neutrino 11 causes free charges to be generated in the target material 132. Fig. 1 further shows a high voltage input 310 attached to an outer region 311 of the semiconductor diode 100. Fig. 1 additionally shows read-out electronics 133 attached to the read-out electrode 131 of the semiconductor diode 100.

[0213] The free charges are generated by the incident neutrino 11 through interaction with a nucleus of the target material 132. The target material is, in this example, germanium and the nucleus is a germanium - 25 nucleus.

[0214] The free charges generated by the interaction of the incident neutrino 11 with the germanium nucleus flow as a charge flow 23, driven by the voltage, to the read-out electrode 131. A neutrino 11 incident on the semiconductor diode 100 generates charge flows 23 consisting of free charges 20. The free charges 20 are collected by the read-out electrode 131 and detected by the read-out electronics 133. Based on the free charges 20 detected by the read-out electronics 133, the read-out electronics 133 generates a sensor signal. In the present example, the sensor signal is further read-out and amplified by the read-out electronics 133. Based on the sensor signal, neutrino events are detected.

[0215] The high-voltage input 310 is used to generate a reverse bias voltage in the target material 132. The reverse bias voltage has an effect of attracting free charges 20 of opposite electrical charge present in the target material 132.

[0216] The sensor signal is a reading of the current or voltage of the free charges collected by the read-out electrode 131 in a predetermined detection window or detection frame.

[0217] The sensor signal is amplified by the read-out electronics 133 and digitized by the data acquisition unit.

[0218] The digitized sensor signal may comprise a detection time, indicating a time, measured for example, by a system clock against a reference time, when the sensor signal was generated; a detection time window, indicating the time interval of the digitized sensor signal shortly before, during, and after the sensor signal formation; and a detection dead time, indicating time counting loss due to, for example, the inclusion of veto signals produced by the anticoincidence veto system 440.

[0219] The target material, according to some embodiments, comprises a high-purity germanium material.

[0220] The target material 132 may be doped such that either a p-type semiconductor or an n-type semiconductor is obtained.

[0221] The outer region 311 of the semiconductor diode 100 may be composed of the same semiconductor as the target material 132, but the outer region 311 may be doped such that a p-type semiconductor is provided if the target material is an n-type semiconductor and vice versa. Free charges 20 are generated in the target material 132 through interaction with incident neutrinos 11. For illustrative purposes, in Fig. 1, neutrinos incident on the semiconductor diode 100 prior to a scattering event are labeled as incident neutrinos 11, while neutrinos following a scattering event are labeled as scattered neutrinos 12.

[0222] According to the function of the semiconductor diode 100 according to the present disclosure, an incident neutrino 11 is scattered by free-free interaction, which may also be called elastic scattering or coherent elastic scattering, with a Ge-nucleus 25.

[0223] Following the scattering event, the scattered neutrino 12 leaves the semiconductor diode 100.

[0224] By interacting with the Ge-nucleus 25, through the released nuclear recoil energy of the struck Ge- nucleus 25 and the subsequent ionization of the electron orbitals of the surrounding Ge-atoms, free charges 20 are generated. Generally, interaction of a neutrino 11 with a Ge-nucleus 25 generates at least one free electron as free charges 20 and an equal number of free holes as free charges 20.

[0225] Note that the Ge-nucleus 25 shown in Fig. 1 is only illustrative. It will be appreciated that an incident neutrino 11 may interact with any of the plurality of Ge-nuclei comprised by the target material 132.

[0226] An electron is an elementary particle with a negative charge. The electron is therefore attracted to a positively charged electrode, such as an anode.

[0227] A hole is a quasi-particle characterized by the absence of a negative charge in an otherwise neutral medium. The hole therefore has a positive charge and is attracted to a negatively charged electrode, such as a cathode.

[0228] The free charges 20 generated by the interaction of the neutrino 11 may be called primary free charges 20. The primary free charges 20 may interact with Ge-atoms present in the target material to produce a cascade of secondary and, in turn, tertiary free charges (not shown). The plurality of primary and possible secondary and tertiary free charges constitute a charge flow 23. The charge flow 23, depending on whether it is positively or negatively charged, corresponding to charge flows consisting of a plurality of free holes and a plurality of free electrons, is moved by the bias voltage provided by the high- voltage input 310.

[0229] According to the embodiment shown in Fig. 1, the bias voltage is provided such that the read-out electrode 131 acts as a cathode, such that the free holes are collected by the read-out electrode 131 as the free charges 20. It will be appreciated that, instead of the read-out electrode 131 acting as a cathode, the read-out electrode 131 may act as an anode, such that free electrons are collected as the free charges 20. According to the present disclosure the read-out electrode 131 may cover a small area of the surface of the target material 132, such as 1 mm2or less.

[0230] The target material 132 in a single semiconductor diode may have a total mass of 1 kg. However, smaller or larger masses of the target material 132 may be provided in accordance with the present disclosure. The target material 132 may be provided in a cylindrical shape or a cubic shape or a cuboid shape or a spherical shape or in another structurally convenient shape. Specifically, the target material 132 may be provided in a shape that allows for a high packing density of a plurality of semiconductor diodes 100.

[0231] It will be appreciated by those skilled in the art that particles other than neutrinos 11 may also interact with the Ge-nuclei 25 comprising the target material 132, generating free charges 20 that may be collected by the read-out electrode 131. As described hereinabove and hereinbelow, the device and / or the detection method according to the present disclosure provides a means to distinguish interactions of neutrinos 11 with the target material 132 and interactions of particles other than neutrinos 11 with the target material 132.

[0232] Suitable components capable of acting as the read-out electronics 133 according to the present disclosure are known from the state of the art, such as, for example, junction-gate field-effect transistors (JFETs) or application-specific integrated circuits (ASICs). Any low intrinsic noise electronic component capable of detecting suitably small electric currents and generating an amplified sensor signal can, in principle, be used.

[0233] Fig. 2 illustrates a visual symbolic representation of a plurality of possible sensor signals generated by the read-out electronics 133. As an example, Fig. 2 shows first exemplary sensor signals corresponding to neutrino scattering signals (line CN1, hereinafter: first neutrino event spectrum CN1), second exemplary sensor signals corresponding to neutrino scattering signals (line CN2, hereinafter: second neutrino event spectrum CN2), exemplary sensor signals corresponding to a detection of gamma rays CG (hereinafter: gamma spectrum CG) and a background spectrum CB. The background spectrum CB is expected if no interaction with a neutrino 11 or particles other than a neutrino 11 occurs.

[0234] Note that Fig. 2 is a visual symbolic representation of possible spectral shapes of an event energy spectrum CS including multiple spectral components. Thus the line CB illustrates, as a spectral component, a background spectrum, the line CG illustrates, as a spectral component, a gamma-ray spectrum, the line CN1 illustrates, as a spectral component, a first neutrino event spectrum and the line CN2 illustrates, as a spectral component, a second neutrino event spectrum.

[0235] The background spectrum is expected to be constant or quasi-flat down to at an energy corresponding to a detector threshold and expected to steeply increase, with decreasing energy, at energies below the detector threshold. In Fig. 2, the detector threshold leading to the background spectrum CB as illustrated is located at an energy of about 80 eV, thus the background spectrum steeply increases, with decreasing energy, at energies lower than about 80 eV.

[0236] As an illustrative example, if the detector threshold was located at an energy of 100 eV, the background spectrum CB would steeply increase, with decreasing energy, at energies lower than about 100 eV. Other detector thresholds are possible but should not be higher than 200 eV.

[0237] The gamma spectrum is expected, if gamma rays are present, to have a maximum at energies higher than energies indicative of neutrino scattering and expected be constant at energies below the maximum.

[0238] By limiting analysis to an energy band with a lower limit as described above, the increase of the background spectrum at energies lower than 80 eV can be disregarded in the analysis. By limiting analysis to an energy band with an upper limit as described above, the maximum of a gamma ray spectrum, if present, can be disregarded in the analysis.

[0239] Note that each line represents an upper edge of a possible spectral component. A spectrum that may be obtained in a measurement may, for example, have a shape similar to the line CB superposed with CN1 or CB superposed with CN2. The gamma spectrum CG may or may not be present. If present, the spectrum obtained in a measurement may have a shape similar to CB superposed with CN1 and CG. If no neutrino is detected, the spectrum may have a shape similar to CB superposed with CG. As the current representation is symbolic, all spectral components shown, i.e. CB, CG, CN1 and CN2, may have slightly different shapes in an actual measurement.

[0240] A maximum energy of a neutrino event spectrum, such as CN1, may be called endpoint energy of the neutrino event spectrum. The endpoint energy is characteristic of the neutrino emission source component that emits the neutrinos forming the neutrino event spectrum. The endpoint energy also depends on the specific detector and an interaction channel. An interaction channel is, for example NNS. The endpoint energy is not the same as a maximum neutrino energy of the neutrinos emitted by the corresponding neutrino emission source component. Instead, the relation between the maximum neutrino energy corresponding to a specific neutrino emission source component depends on the material used in the detector and material-specific quenching. An illustrative example of a possible relation for a detector is given in the following table:

[0241] By using a detector threshold of 200 eV, the above neutrino emission source components and others may be recognized with accuracy.

[0242] The event energy spectrum CS is generated based on a plurality of sensor signals. In order to generate the event energy spectrum CS, each sensor signal is analyzed in order to determine an energy of that sensor signal. The energy of the sensor signal is, for example, determined based on a maximum voltage or a maximum current of the sensor signal. Specifically, the energy of the sensor signal is a deposited energy of the incident neutrino calculated on a basis of the signal voltage and / or current.

[0243] Note that an event does not indicate a neutrino interaction of a neutrino emission, but rather a sensor signal measured by the read-out electronics. The event may or may not have been caused by a neutrino. Rather, statistically, the number of events is correlated with the number of neutrino interactions. The correlation is statistically linear, though the exact shape of the correlation may be known or unknown. However, knowledge of the exact shape of the correlation is not required in all embodiments of the present disclosure.

[0244] The event energy spectrum CS is produced based on the energy of the sensor signals and the number of sensor signals at a certain energy.

[0245] In tangible embodiments of the present disclosure, the event energy spectrum CS is provided in a suitable digital form, such as a numeric array, list, binary object or any other digital form capable of storing a spectrum.

[0246] The neutrino-nucleus scattering events are, subsequent to generating the event energy spectrum CS, identified by analyzing the event energy spectrum CS.

[0247] The background spectrum CB is composed of signals from a plurality of other background particles other than the neutrino 11 that interact with the target material after passing shielding, such as the multilayer radiation shield, and of noise events appearing below the energy detection threshold. The more efficient the background radiation shield, the more efficient, due to a better signal-to- background ratio, the detection of neutrinos 11 by the neutrino detection device can be expected.

[0248] The lower the noise level, the lower the energy neutrino detection threshold and the more efficient, due to a better signal-to-noise ratio, the detection of neutrinos 11 by the neutrino detection device can be expected.

[0249] According to the present disclosure, detection of free charges 20 corresponding to an energy less than 200 eV of deposited energy should be provided.

[0250] Any analyzed sensor signal may be, plotted in a graph with a first axis Al, representing an energy in units of electronvolt (eV) and a second axis A2, representing the energy of the sensor signals. Therefore, a plurality of analyzed sensor signals may be represented as an energy spectrum.

[0251] A sensor signal is amplified by the read-out electronics 131 by detecting free charges 20, and digitized, collected and analyzed by the data acquisition unit determining the energy of each sensor signal and attributing each analyzed sensor signal to an energy bin inside an energy spectrum.

[0252] The sensor signal may comprise a detection time, indicating a time, measured for example, by a system clock against a reference time, when the sensor signal was generated.

[0253] The length of the time interval may be set in advance and may, for example, be 10000 nano-seconds. However, longer or shorter times intervals may be provided. The time interval may be called a detection time window.

[0254] The detection time window may be a static window. In a static window free charges are detected and aggregated in a single number for the length of the time interval and the single number is reset to zero. The time interval defining the detection window may define a neutrino detector cadence.

[0255] The goal of analysis of the sensor signal is to distinguish the gamma spectrum CG and / or the background spectrum CB from the neutrino spectra CN1, CN2.

[0256] As shown in Fig. 2, analyzed neutrino spectra CN1, CN2 have a characteristic spectral shape that distinguishes them from, for example, a gamma spectrum CG consisting of a flat component and a symmetric peak. As can be seen, each example neutrino spectrum CN1, CN2 has, in the present illustration, a maximum at energies around 300 eV, whereas the gamma spectrum CG can have a maximum at energies well above 300 eV.

[0257] The rate of a neutrino spectrum CN1, CN2 may be detected by integrating over the characteristic shape of the neutrino spectrum CN1, CN2. Alternatively, pattern recognition may be employed to recognize the characteristic spectral shape of the neutrino spectra CN1, CN2. If a plurality of analyzed sensor signals corresponds to the less specific background or noise spectrum CB below the energy detection threshold, or if neither a neutrino spectrum CN1, CN2 nor a gamma spectrum CG is detected, no particles may have been detected but only noise events.

[0258] Recognizing a characteristic shape of the neutrino spectrum CN1, CN2, as described above, may be called analyzing the sensor signal.

[0259] Analyzing a sensor signal may, as described hereinbelow, be further based on the analysis of a plurality of veto signals. A veto signal is provided by an anticoincidence veto system 440 configured to detect ionizing radiation that should not be detected, such as cosmic radiation, and has a certain veto interval. Any sensor signal detected within a veto interval will be rejected.

[0260] Fig. 3A is a visual representation of a possible energy spectrum CS measured by the neutrino detection device. The present spectrum may, for example, correspond to the neutrino spectrum CN1 (as shown in Fig. 2) superposed with the background spectrum CB (as shown in Fig. 2).

[0261] Fig. 3B is a visual representation of another possible energy spectrum CS measured by the neutrino detection device. The present spectrum may, for example, correspond to the neutrino spectrum CN2 (as shown in Fig. 2) superposed with the background spectrum CB (as shown in Fig. 2). Note the difference of the spectrum in comparison to Fig. 3B. Note further that the specific shape of the measured spectrum CS will depend on the circumstances of the measurement, such as a type of the neutrino emitter, strength of the neutrino emitter, distance to the neutrino emitter, duration of the measurement and the like.

[0262] Fig. 4 illustrates detection, according to a basic embodiment, of a neutrino emission signal using the neutrino detection device. The method is based on detecting an excess of sensor events in an energy band as described hereinabove. The energy band is, in Fig. 4, labelled “Band 1” and ranges from a lower energy limit Ei, which, in the illustrated embodiment is set at 60 eV, but may be lower, including 0 eV or higher than 60 eV, to an upper energy limit E2, which, in the illustrated embodiment is set at 300 eV, but may be more or less than 300 eV.

[0263] Fig. 4A shows an illustration of a measured spectrum CS in a measurement operation at a first time ti, which may be a time subsequent to starting a measurement or a time at the start of the measurement operation. Fig. 4A shows an illustration of a measured spectrum CS in the measurement operation at a second time C, which may be a time subsequent to E

[0264] For example, measurement may be started at a time to.

[0265] The difference in time between ti and t2may be called the measuring window At. At may be defined as At — t2— ti. Note that the spectrum CS has changed between Fig. 4A and Fig. 4B and that the background spectrum CB has likewise increased.

[0266] We emphasize again that the depiction in Figs. 4A and 4B are merely illustrative of a spectrum that may be obtained. For example, a spectrum may also include a superposed component due to gamma radiation, as illustrated by CG in Fig. 2.

[0267] The excess of sensor events may be a total number of excess events in terms of total event number or an excess event rate.

[0268] In an energy spectrum, the total event number arises from integrating the spectrum with respect to the energy. The excess of the spectrum in terms of total event number can visually be represented as the background spectrum CB (cf. Fig. 2), visualized as the dashed line in Figs. 4A and 4B, subtracted from the total event number of the spectrum CS. The total event number of the background spectrum CB may be obtained by integrating the background spectral flux SCB over the energy band and the time At. The remaining total number of excess events can be visualized as the hatched area A(ti) in Fig. 4A or the hatched area

[0269] Neutrino emission may simply be detected by determining the size of the hatched area, i.e. the total number of excess events to be greater than zero.

[0270] Alternatively, neutrino emission may be detected by determining that the size of the hatched area A(ti), measured at ti and the size of the hatched area measured at C, is different from each other, with A(ti) being smaller than

[0271] Specifically, the detection process in one embodiment can be described as follows:

[0272] In a first step, at a time to, the measurement process is started. In a second step, the detector is operated for a time between to and ti, at ti, the spectrum is read out.

[0273] The total number of events is then calculated by integrating the spectrum in the energy band to obtain the total number of events in the spectrum:

[0274] The total number of background events is calculated by integrating the background spectral flux (obtained, for example, in a background measurement procedure as described above), by the energy band and the measurement time:

[0275] A total number of gamma events NCG may likewise be determined. The total number of excess events A(ti) may then be determined as:

[0276] In a basic embodiment, the number A(ti) is the number of detected neutrino events.

[0277] In a second alternative, neutrino detection can be accomplished by comparing the spectra at two times ti and t2, the comparison comprising calculation of a normalized ratio R of the excess events A(ti) and

[0278] If R differs significantly from unity, then the relative number of excess events with respect to the total number of events, has changed in the time between ti and / ?, indicating that NNS events have been detected.

[0279] Fig. 5 illustrates a method to estimate a change in neutrino emission from a neutrino emission source.

[0280] The spectrum shown in Fig. 5A may be the same spectrum as the spectrum shown in Fig. 4A or Fig. 4B. As described with respect to Fig. 4, a difference of the total number of excess neutrinos AA(t) — A(t) -A(ti) is measured in a time At = t - , as shown in Fig. 5B. The total number of excess neutrinos can be plotted with respect to time, as shown in Fig. 5B. Fig. 5B shows the total number of excess neutrinos A(t), measured at a time t in the duration from ti to / with respect to time. Since the total number of excess events is aggregated, the number continually increases with time.

[0281] From the difference of the total number of excess neutrinos AA(t), an event rate F(t) can be calculated through:

[0282] The event rate F(t) can be, as illustrated in Fig. 5C, plotted with respect to time. A change in a neutrino emission rate from a source located in a vicinity of the detector can be detected by determining that, over time, the event rate changes from a first rate Rt, where it previously remained largely constant, to a second rate R^, where is subsequently remains largely constant, as shown in Fig. 5C. The change may, as shown, be an increase, indicating an increase in neutrino emission, or a decrease, indicating a decrease in neutrino emission.

[0283] Fig. 6 illustrates detecting neutrino emission based on a gradient G of the event energy spectrum CS. The gradient is a gradient of the spectrum with respect to the energy E, i.e. G =dN^E^asdescribed hereinabove in equations (1) and (2). Neutrino emission is detected by calculating the gradient G (indicated in Fig. 6A) in the energy band “Band 1”, for example as described hereinabove. Alternatively, the gradient may be a gradient of a linear regression function that is fitted to the event energy spectrum CS in the energy band “Band 1”.

[0284] The gradient G can, for illustrative purposes, be plotted with respect to time, as shown in Fig. 6B. A neutrino emission may be detected by determining if the gradient G falls below a certain threshold Tt. Ttindicates a predetermined real value of the gradient of the event energy spectrum CS. If G falls below the threshold T? it is apparent that the shape of the event energy spectrum CS differs from the background spectrum CB and the, possibly present, gamma spectrum CG, such that the presence of a neutrino spectrum CN1 / 2 can be inferred.

[0285] The value of the gradient depends on the type of neutrino emission source, with a first neutrino emission source component leading, for example, to the generation of a neutrino signal CN1 with a specific gradient G. Thus, by determining the gradient G to fall into a range between the first threshold value Ttand the second threshold value T2, a first neutrino emission source component can be identified. Note that the calculation of the gradient and comparison with the threshold values T? and T2, as described with respect to Fig. 6 corresponds to the calculation and comparison set out in equations (1), (2) and (3) above.

[0286] Fig. 7 shows a method to detect neutrino signals according to a first embodiment. In detection step S71, free charges are collected by the read-out electrode 131. Based on the free charges, the read-out electrode 131 generates sensor signals. In parallel, veto signals are produced in a veto signal generation step S74 by the anticoincidence veto system. In a spectrum generation step S72, an event energy spectrum CS is generated based on the acquires sensor signals and veto signals are combined to generate the event energy spectrum CS as described hereinabove. For each received veto signal, sensor signals in a veto interval are rejected, while for each sensor signal, an energy is calculated and the event aggregated in the event energy spectrum CS.

[0287] In an analysis step S73, the spectrum is analyzed in order to detect neutrino signals, as described hereinabove with respect to Fig. 2, Fig. 3, Fig. 4, Fig. 5 and Fig. 6.

[0288] Fig. 8 shows an embodiment of the analysis step S73 in Fig. 7. In step S81, the event energy spectrum CS is obtained as described hereinabove.

[0289] In a shape recognition step S82, a shape of the event energy spectrum CS is recognized. For example, the shape recognition may be the calculation of the gradient of event energy spectrum CS in an energy band, as described with respect to Fig. 6 hereinabove. In a detection step S83, the neutrino events are determined neutrino events is calculated. Specifically, the neutrino events are the events subtending the specific gradient of, for example, CN1 or CN2.

[0290] In other words: The gradient may be seen as approximate fitting model of a characteristic spectral shape expected in coherent elastic NNS.

[0291] In addition, in step S83, the number of neutrino events can be calculated. The number of neutrino events is the total number of excess events A(t) as described, for example, with respect to Fig. 4 and Fig. 5 hereinabove.

[0292] Fig. 9 shows a method to determine a number of neutrino events based on the event energy spectrum CS. In step S91, the event energy spectrum CS is obtained as is step S81. In step S92, the background spectrum is subtracted from the event energy spectrum CS. The remaining spectrum is integrated in order to obtain the number of neutrino events as the total excess events A(t) as described hereinabove. Step S93 corresponds to equations (4), (5) and (6) above.

[0293] Fig. 10 shows a method to identify a specific neutrino emission source based on the gradient of the event energy spectrum CS. It should be noted that, prior to the start of the method, the event energy spectrum CS is obtained as described hereinabove, e.g. in Fig. 7.

[0294] In a first step S101, the gradient is calculated as described with respect to equation (1) and (2) and Fig. 6. In a comparison step S102, the gradient is compared with a predetermined comparison value C (note that, as described hereinabove, there may be more than one predetermined comparison value C, each associated with a certain neutrino emitter), as described hereinabove with respect equation (3) and Fig. 6.

[0295] If the gradient matches a comparison value (“yes” in step S104) resulting from a decision step 103, then, the corresponding neutrino emitter is identified (step S104) as the neutrino emission source. If the gradient does not match any predetermined comparison value (“yes” in step S105), no specific neutrino emission source is identified (S105).

[0296] Fig. 11 shows a method for detecting a neutrino emission source. In a first step Sill, the monitoring apparatus (detector) is placed in chosen monitoring location. In a second step SI 12, a neutrino emission source is detected by monitoring the gradient, as described with respect to equation (1) and (2), Fig. 6 and Fig. 10 hereinabove.

[0297] Subsequent steps S113, S114, SI 15 and SI 16 correspond to step S102, S103, S104 and S105 in Fig. 10. Thus, a neutrino emission source in the vicinity of the monitoring location can be detected and identified. Fig. 12 shows a semiconductor diode 100 included in a cryocooling device 200. Cryocooling of the semiconductor diode 100 is required in order to suppress undesirable thermal electrons generated in the target material 132 which would add to the background spectrum and noise spectrum CB, thereby lowering the signal-to-noise ratio.

[0298] The cryocooling device 200 comprises a cryostat end cap 210, a cooling rod 220, a cryostat arm 230, a cryogenic temperature generator 240, a low-power voltage supply 330, a high-power voltage supply 320, the high-power voltage input 310 and the radiation detection unit 101. The cryostat end cap 210, a cooling rod 220, a cryostat arm 230 together may be called the cryostat system.

[0299] Each of the cooling rod 220, cryostat arm 230, cryogenic temperature generator 240, low power voltage supply 330, high-power voltage supply 320, high-power input 310 and radiation detection unit 101 may be configured to be removable from the cryocooling device 200 when the neutrino detector is not in operation.

[0300] The semiconductor diode is housed in the cryostat end cap 210. The cooling rod 220 is connected to the radiation detection unit 101 and the cryostat arm 230. The cryostat arm 230 is connected to the cooling rod 220 and the cryogenic temperature generator 240. The connection of each element 100, 220, 230, 240 is such that an efficient thermal connection between the radiation detection unit 101 and the cryogenic temperature generator 240 is established. Furthermore, the cryocooling device 200 provides a vacuum and an efficient thermal insulation against external heat sources. The cryocooling device 200 is configured such that a temperature of the radiation detection unit 101 lower than 100 K can be achieved.

[0301] The high-power voltage supply 320 is electrically connected to the high-power voltage input 310 and is configured to provide the voltage necessary to maintain the reverse bias voltage in the radiation detection unit 101. The high-power voltage supply 320 may be connected to an external power generator.

[0302] The low power voltage supply 330 is electrically connected to the read-out electronics 131 and the cooling unit and is configured to provide the voltage necessary to operate the read-out electronics 131 and the cooling unit. The low power voltage supply 330 may be connected to an external power generator.

[0303] The read-out electronics 131 is connected, for example via a signal transmission line 235, to the data acquisition unit.

[0304] Fig. 13 shows a schematic illustration of one embodiment of the neutrino detector 400 according to the present disclosure. The neutrino detector 400 comprises an airborne radiation shield system 410, high-density material layers 420, a low-density material layer 430, an anticoincidence veto system 440, a power generator 450, a data acquisition unit 460, a control unit 470, a cavity 401 and the cryocooling device 200 including the radiation detection unit 101 (as described, in Figs. 12 and 1 respectively, above). The airborne radiation shield system 410, high-density material layers 420, low-density material layer 430 and the anticoincidence veto system 440 may be part of the multilayer radiation shield.

[0305] The high-density material layers 420, low-density material layer 430 and the anticoincidence veto system 440 are disposed in an onion-like shell structure. In the shell structure, a first high-density material layer 420a surrounds the anticoincidence veto system 440, comprising scintillation devices 441. The anticoincidence veto system 440 surrounds the low-density material layer 430. The low- density material layer 430 surrounds a second high-density material layer 420b. The second high- density material layer 420b forms the cavity 401 which houses the cryostat end cap 210, including the radiation detection unit 101.

[0306] Note that a larger or smaller number of low-density material layers 430 than shown in Fig. 13 may be provided in accordance with the present disclosure. A spatial arrangement of the low-density material layer 430, or, if more than one are provided, low-density material layers 430 may be adapted according to the environment of the detector 400. For example, a thickness of the low-density material layer 430 or low-density material layers 430 may be higher in a direction with a neutron radiation source.

[0307] Equivalently a larger or smaller number of high-density material layers 420 than shown in Fig. 13 may be provided in accordance with the present disclosure. A spatial arrangement of the high-density material layer 420, or, if more than one is provided, high-density material layers 420 may be adapted according to the environment of the detector 400. For example, a thickness of the high-density material layer 420 or high-density material layers 420 may be higher in a direction with a known radiation source. The shielding provided by the high-density material layer 420, if more than one are provided, should be equivalent to at least 15 cm of lead. However, note that the shielding may include environmental shielding that is only present in a surrounding of the detector, but not part of the detector. For example, a building that the detector is located in, or a wall interposed between the detector and a radiation source may augment the shielding provided by the high-density material layer 420. Thus, the shielding provided by the high-density material layer 420 in addition to environmental shielding should be equivalent to 15 cm of lead.

[0308] The cryocooling device 200 is disposed such that the cryostat end cap 210 is fully housed in the cavity 401, while the cryogenic temperature generator 240, the low power voltage supply 330 and the high- power voltage supply 320 are located outside of the first high-density material layer 420a. The cryostat arm 230 penetrates the high-density material layers 420, the low-density material layer 430 and the anticoincidence veto system 440 such that, as described a thermal connection between the cryogenic temperature generator 240 and the radiation detection unit 101 is established via the cooling rod 220, the cooling rod 200 also being housed in the cavity 401.

[0309] The purpose of the high-density material layers 420 is to prevent ionizing radiation, such as high energy photons, alpha radiation, beta radiation, and the like from entering the radiation detection unit 101. This is required as the ionizing radiation may lead to the generation of free charges in the target material without an involvement of a neutrino 11. This cannot fully be prevented, which necessitates analysis of the sensor signal as described hereinabove and inclusion of the anticoincidence veto system 440 as described hereinbelow.

[0310] The high-density material layers 420 may be composed of layers of a thickness of at least 15 cm of lead, where lead of low intrinsic radioactivity is to be used at least for an innermost layer. Alternatively, the high-density material layers 420 may be composed of any other high-density material of a thickness sufficient to provide protection against ionizing radiation equivalent to 15 cm of lead.

[0311] The purpose of the low-density material layer 430 is to prevent neutron radiation and the like from entering the semiconductor diode 100. Since neutrons can scatter elastically like neutrinos off Ge nuclei, allowing neutrons into the semiconductor diode 100 may likewise lead to a generation of sensor signals that can mimic neutrino signals. The low-density material layer 430 may be composed of layers of a thickness of at least 10 cm of a hydrogen-rich material doped with, for example, boron or gadolinium.

[0312] The purpose of the anticoincidence veto system 440 is to detect mainly high-energy ionizing cosmic radiation such as, for example, muons and muon showers, that cannot be sufficiently stopped by the high-density material layers 420, intersecting easily the semiconductor diode 100. The anticoincidence veto system 440 may be provided with its own control unit (not shown) or use the data acquisition unit 460 and the control unit 470 of the neutrino detector 400. The anticoincidence veto system 440 is configured to generate a veto signal if a cosmic radiation particle is detected. The veto signal is then used in the analysis of the sensor signal as described in connection to Figs. 2 to Fig. 11.

[0313] The anticoincidence veto system 440 may be based on any of a number of suitable known technologies, such as a multiwire proportional counter. However, the anticoincidence veto detector 440 may in particular be a scintillation detector. In a scintillation detector, in response to ionizing radiation incident on the detector volume, scintillation light is induced and sensed by a scintillation light detection device.

[0314] The anticoincidence veto detector may be provided as a plastic scintillator plate of a thickness of at least 5 cm. The airborne radiation shield system 410 is connected to the cavity 401, for example via a pipe 411, such that gas generated or released by the airborne radiation shield system 410 can be provided in the cavity 401. The pipe penetrates the high-density material layers 420, the low-density material layer 430 and the anticoincidence veto system 440 such that the airborne radiation shield system 410 is connected to the cavity as described.

[0315] The purpose of the airborne radiation shield system 410 is to provide an atmosphere exhibiting low intrinsic radioactivity in the cavity 401, additionally lowering the background radiation the semiconductor diode 100 is exposed to. The airborne radiation shield system 410 may specifically be configured to provide a radon-free air or radon-free nitrogen atmosphere in the cavity 401.

[0316] By providing an atmosphere exhibiting low intrinsic radioactivity in the cavity 401, airborne radiation present in the environment is suppressed. This way, an intrinsic radioactivity below 1 Radon decay / sec / m3can be achieved.

[0317] By providing the high-density material layers 420, the low-density material layer 430, the anticoincidence veto system 440 and the airborne radiation shield system 410, background radiation, leading to the background spectrum CB, can be reduced by three to four orders of magnitude.

[0318] The power generator 450 is configured to provide power to the neutrino detector 400 and is electrically connected in particular to the low power voltage supply 330 and the high-power voltage supply 320. The power generator 450 may be a self-contained unit, such as a combustion generator, a fuel cell or the like, or may be connected to an exterior power system, such as a general electrical power grid.

[0319] The data acquisition unit 460 is configured to digitize, collect and analyze data, for example the amplified sensor signals 31 generated by the semiconductor diode and amplified by the read-out electronics, or the veto signals generated by the anticoincidence veto system as described in connection to Figs. 2 to 11.

[0320] The control unit 470 provides control and interface capabilities to the neutrino detector. Specifically, the control unit 470 may be used to control the power generator 450, the airborne radiation shield system 410, the anticoincidence veto system 440 or any other component of the neutrino detector. Furthermore, the control unit may be an interface device to be accessed by an operator of the neutrino detector. The control unit may provide communications capabilities, such as data transmission and reception. The control unit may comprise a CPU (Central Processing Unit), a hard drive, RAM (Random Access Memory), a keyboard, a monitor and other components as required. Specifically, the control unit may be a personal computer. The control unit is connected through data transmission means, in particular, to the data acquisition unit 460 and / or the read-out electronics 131. In some embodiments, the control unit 470 and the data acquisition unit 460 may be identical.

[0321] Fig. 14 shows a schematic illustration of another embodiment of the neutrino detector 400, comprising a plurality of radiation detection units 101 according to the present disclosure.

[0322] The neutrino detector 400 comprises an airborne radiation shield system 410 (not shown), high- density material layers 420, a low-density material layer 430, an anticoincidence veto system 440, a power generator (not shown), a data acquisition unit 460 (not shown), a control unit (not shown) and a cavity 401.

[0323] Unlike the neutrino detector shown in Fig. 13 above, the neutrino detector shown in Fig. 14 comprises a plurality of target neutrino detectors 100 housed in the same cavity 401. Each target neutrino detector is provided with an individual cryocooling device 200 as described in connection with Fig. 12 above, wherein the components of each cryocooling device 200 are disposed as shown with respect to Fig. 13 above.

[0324] Specifically, each cryocooling device 200 is disposed such that the cryostat end cap 210 of each cryocooling device 200 is fully housed in the cavity 401, while the cryogenic temperature generator 240 of each cryocooling device 200, the low power voltage supply 330 of each cryocooling device 200 and the high-power voltage supply 320 of each cryocooling device 200 are located outside of the first high-density material layer 420a. The cryostat arm 230 of each cryocooling device 200 penetrates the high-density material layers 420, the low-density material layer 430 and the anticoincidence veto system 440 such that, as described a thermal connection between the cryogenic temperature generator 240 of each cryocooling device 200 and the semiconductor diode 100 of each cryocooling device 200 is established via the cooling rod 220 of each cryocooling device 200, the cooling rod 200 of each cryocooling device 200 also being housed in the cavity 401.

[0325] Each cryocooling device 200 is supplied with power by the not shown power generator and provided with a data link to the not shown data acquisition unit and the not shown control unit.

[0326] The not shown airborne radiation shield system is disposed as in the neutrino detector shown in Fig. 13 above.

[0327] Fig. 15 shows a setup for reactor monitoring using the neutrino detector 400 provided in a vehicle. The vehicle 600 comprising the neutrino detector 400 is placed in a vicinity of a nuclear reactor 500. The neutrino detector 400 may be placed outside a restricted area protection 520. A reactor neutrino flux 510 is emitted isotropically by the nuclear reactor 500. The reactor neutrino flux 510 is detected by the neutrino detector 400 included in the vehicle at the given place in a given distance to the reactor. Based on the detected neutrino energy spectrum and neutrino rates, the nuclear fuel composition within the fuel rods 501 of the nuclear reactor 500 can be calculated in a certain time period. Instead of a vehicle 600, the neutrino detector 400 may also be provided individually without a vehicle.

[0328] The nuclear fuel can be called a neutrino emission source or neutrino emitter, and the nuclear fuel components can be called neutrino emission source components.

[0329] Fig. 16 shows a method for reactor monitoring using the neutrino detector 400 according to the present disclosure.

[0330] In a first Step S161, the neutrino detector 400 is placed in a vicinity of an artificial neutrino source, specifically, a nuclear reactor 500. The neutrino detector 400 may be placed inside or outside a restricted area protection 520. Since reactor neutrinos 510 have a low interaction probability with matter they can travel easily through a restricted area protection 520 or another large and dense obstacle.

[0331] In a second Step S162, the neutrino detector 400 measures sensor signals and analyzes the energy spectrum. Further, the neutrino detector 400 identifies a plurality of reactor neutrino spectra CN1, CN2 and differentiates them from the background spectrum and noise spectrum CB as described hereinabove.

[0332] In a third Step S163, the neutrino detector 400 monitors a plurality of signal rates obtained from the spectral contributions of the reactor neutrino spectra CN1, CN2. Since the rates of the reactor neutrino spectra CN1, CN2 are correlated with the decay rates of the fission products in the fuel rods 501 of a nuclear reactor 500, it is possible to monitor the nuclear fuel composition as a function of time.

[0333] Fig. 17 shows a setup for geological-radiochemical sensing using the neutrino detector 400, which may be the neutrino detector 400 described in Fig. 12, mounted on a vehicle 600 as described in Fig. 15. The vehicle 600 comprising the neutrino detector 400 is moved to a plurality of locations on a geographical surface.

[0334] The geographical surface can be, for example, a surface above or below sea level. At a given position of the vehicle 600a, 600b, geological neutrinos 511 from naturally occurring radioactive decay in the Earth’s crust 521 are sensed with the neutrino detector 400. By monitoring geological neutrino signal rates in a plurality of locations along the terrestrial surface, the method allows to measure the radioisotopic composition in the Earth’s crust 521 as a function of the vehicle position. Since a radioisotopic abundance above (or below) a calculated mean value indicates the presence of a raw material resource 502 in the Earth’s crust 521, it is possible to localize a raw material resource 502 within the Earth’s crust 521 using a non-invasive method as described here.

[0335] Fig. 18 shows a method for geological-radiochemical sensing using the neutrino detector 400 according to the present disclosure.

[0336] In a first Step S181, the neutrino detector 400 is transported within a vehicle 600 to a plurality of locations along the geographical surface, which may lie above or below sea level.

[0337] In a second Step S182, the neutrino detector 400 measures at each location sensor signals and analyzes the energy spectrum. Further, the neutrino detector 400 identifies a plurality of geological neutrino spectra CN1, CN2 and differentiates them from a plurality of background radiation signals and noise spectrums CB as described hereinabove.

[0338] In a third Step S183, the neutrino detector 400 measures a plurality of rates obtained from the spectral contributions of the geological neutrino spectra CN1, CN2 at the plurality of locations.

[0339] In a fourth Step S184, the neutrino detector 400 produces a two-dimensional map showing the neutrino signal rates as a function of the measured locations. Locations with enhanced or depleted neutrino signal rates indicate the presence of raw material resource 502 within the Earth’s crust.

[0340] Fig. 19 shows a setup for neutrino-based telecommunication using the neutrino detector 400 according to the present disclosure. The neutrino-based telecommunication method uses the neutrino detector 400, which may be the neutrino detector 400 described in Fig. 13 or Fig. 14, and a controlled artificial neutrino source 503.

[0341] The artificial neutrino source 503 produces a modulated neutrino transmission 512 with an encoded modulated neutrino emission flux. The artificial neutrino transmission 512 traverses a solid or liquid object 522. Due to the low interaction probability of neutrinos 11 with matter, the solid or liquid object 522 may have an extension of up to several 1000 km without a notable absorption of the neutrinos 11 of the neutrino transmission 512.

[0342] After traversing the solid or liquid object 522, the traversing neutrino transmission 512 may be detected by the neutrino detector 400, by which a modulated neutrino signal rate may be measured.

[0343] By comparing the detected modulated neutrino rate with the same encoding used for the neutrino emission flux, it is possible to decode the transmitted information.

[0344] Fig. 20 shows a method for neutrino-based communication using the neutrino detector according to the present disclosure. In step S201, information is encoded in a modulated signal. The information may, for example, be a text message. The text may, for example, be encoded using Morse-code. In Step S202, a modulated neutrino transmission 512 is generated based on the modulated signal using a controlled neutrino source. The controlled neutrino source may, for example, be a particle accelerator.

[0345] In step S203, the modulated neutrino signal is detected using the neutrino detector 400.

[0346] In step S204, the modulation of the modulated neutrino signal is determined using a suitable analysis provided, for example, by circuitry and the signal is decoded using the same encoding as in Step S201.

[0347] This way, information may be transmitted using neutrinos. Using neutrinos, messages may be transmitted through solids or liquids without requirement of line-of sight. The information may further be transmitted through solids or liquids that would be impermeable to conventional, especially electromagnetic, signals.

[0348] It should be recognized that the embodiments describe methods with an exemplary ordering of method steps. The specific ordering of method steps is however given for illustrative purposes only and should not be construed as binding.

[0349] All units and entities described in this specification and claimed in the appended claims can, if not stated otherwise, be implemented as integrated circuit logic, for example on a chip, and functionality provided by such units and entities can, if not stated otherwise, be implemented by software.

[0350] In so far as the embodiments of the disclosure described above are implemented, at least in part, using software-controlled data processing apparatus, it will be appreciated that a computer program providing such software control and a transmission, storage or other medium by which such a computer program is provided are envisaged as aspects of the present disclosure.

[0351] Note that the present technology can also be configured as described below.

[0352] (1) A neutrino detection device 400, comprising: a radiation detection unit 101 comprising a semiconductor diode 100 configured to act as both target 132 and sensor, and read-out electronics 133 comprising a read-out electrode 131 configured to sense free charges 20 generated in the target 132, wherein the read-out electronics 133 is configured to generate, based on the free charges 20, sensor signals; and a data acquisition unit 460 configured to identify, based on the sensor signals, neutrino-nucleus-scattering events.

[0353] (2) The device 400 according to (1), wherein the data acquisition unit 460 is configured to determine an event energy spectrum CS based on the sensor signals, and to determine neutrino-nucleus- scattering events based on the event energy spectrum CS.

[0354] (3) The device 400 according to (2), wherein the data acquisition unit 460 is configured to identify the neutrino-nucleus-scattering events based on an increase of the event energy spectrum CS. (4) The device 400 according to any one of (2) or (3), wherein the data acquisition unit 460 is configured to identify the neutrino-nucleus -scattering events based on an increase of the event energy spectrum CS as compared to a predefined nominal event energy spectrum CB.

[0355] (5) The device 400 according to (4), wherein the nominal event energy spectrum CB is a prestored spectrum that has been determined in a background measurement process conducted in absence of a neutrino source in a vicinity of the detector 400.

[0356] (6) The device 400 according to any one of (2) to (5), wherein the data acquisition unit 460 is configured to determine the neutrino-nucleus-scattering events based on the event energy spectrum CS at energies that are indicative of neutrino-nucleus-scattering events.

[0357] (7) The device (400) according to claim 6, wherein energies that are indicative of neutrino-nucleus- scattering events are energies of 1000 eV or less.

[0358] (8) The device 400 according to any one of (2) to (7), wherein a low energy detection threshold of less than 200 eV is achieved by comprising a very low noise radiation detection unit and a very low noise read-out electronics; and by a data acquisition system able to reconstruct sensor signal energies lower than 200 eV.

[0359] (9) The device 400 according to any one of claims (2) to (8), wherein identifying the neutrino-nucleus - scattering events comprises determining a shape and a gradient of the event energy spectrum CS.

[0360] (10) The device 400 according to any one of (2) to (9), wherein identifying the neutrino-nucleus- scattering events comprises determining an integrated count rate A of the event energy spectrum CS.

[0361] (11) The device 400 according to any one of (2) to (10), wherein the data acquisition system is further configured to recognize, based on the event energy spectrum CS, a neutrino emission source and neutrino emission source components.

[0362] (12) The device 400 according to (11), wherein the neutrino emission source is recognized based on the shape or gradient G of the event energy spectrum CS, or based on the integral count rate A of the event energy spectrum CS.

[0363] (13) The device 400 according to any one of (1) to (12), wherein the semiconductor diode 100 is configured as a p-n junction and operated with a reverse bias voltage.

[0364] (14) The device 400 according to any one of (1) to (13), wherein the semiconductor diode 100 is a semiconductor high-purity germanium diode 100 and the read-out electronics 133 is a very low noise read-out electronics 133 and the read-out electrode 131 is a point-like read-out electrode 131. (15) The device 400 according to any one of (1) to (14), further comprising a cryocooling device 200, configured to perform cryocooling of the device 400.

[0365] (16) The device 400 according to any one of (1) to (15), wherein the radiation detection unit 101 is operated at a temperature of less than 100 K.

[0366] (17) The device 400 according to any one of (15) or (16), wherein the cryocooling device 200 comprises a cryogenic temperature generator; and a cryostat system; wherein the cryostat system connects the radiation detection unit 101 to the cryogenic temperature generator, such that the cryogenic temperature generator can be used to perform cooling of the radiation detection unit 101.

[0367] (18) The device 400 according to any one of (1) to (17), further comprising a multilayer radiation shield that shields the radiation detection unit 101 against background radiation, wherein the radiation detection unit 101 is housed in the multilayer radiation shield.

[0368] (19) The device 400 according to (18), wherein the multilayer radiation shield comprises one or more high-density material layer 420, wherein the high-density material layer 420 comprises a high-density material, the high-density material further having a low amount of intrinsic self-radiation.

[0369] (20) The device 400 according to any one of (18) to (19), wherein the multilayer radiation shield comprises one or more low-density material layers 430, wherein the low-density material layer 430 comprises a low-density material, the low-density material further having material properties providing a high neutron moderation capability and / or a high neutron capture capability.

[0370] (21) The device 400 according to any one of (18) to (20), wherein the low-density material is a mixture of materials.

[0371] (22) The device 400 according to any one of (18) to (21), wherein the multilayer radiation shield comprises an airborne radiation shield system 410, which suppresses airborne radiation penetrating the multilayer radiation shield by providing, in an interior 401 of the multilayer radiation shield, an atmosphere with low intrinsic radioactivity.

[0372] (23) The device 400 according to any one of (18) to (22), wherein the multilayer radiation shield comprises an anticoincidence veto system 440 configured to detect incident cosmic radiation, and to generate a veto signal with a predetermined veto interval following a detection of incident cosmic radiation, and to transmit the veto signal to the data acquisition system 460.

[0373] (24) The device 400 according to any one of (18) to (23), wherein the data acquisition system 460 is further configured to reject, based on reception of the veto signal, sensor signals during the veto interval. (25) The device 400 according to any one of (17) to (24), comprising a plurality of the radiation detection unit 101; and a plurality of the read-out electronics 133; and one or more of the data acquisition systems 460, wherein one each of the data acquisition system 460 analyzes the sensor signals from at least one of the radiation detection units 101; a plurality of the cryocooling devices 200, wherein each one of the radiation detection units 101 is housed in one each of the cryostat systems; and one multilayer radiation shield surrounding the cryostat systems.

[0374] (26) A vehicle 600, comprising the device 400 according to any one of (1) to (25).

[0375] (27) A neutrino detection method, comprising: Sense free charges 20 generated in a target 132, generate, based on the sensed free charges 20, a sensor signal, and identify, based on a plurality of the sensor signals and the reconstructed event energy spectrum CS, neutrino-nucleus -scattering events.

[0376] (28) A reactor monitoring method, the method comprising: measure with a device 400 according to any one of (1) to (25) located at a detector position a plurality of neutrino-nucleus-scattering events during a monitoring period and recognize, based on the neutrino-nucleus-scattering events, a reactor neutrino emission source and changes in the reactor fuel composition in a given reactor.

[0377] (29) The monitoring method according to (28), further comprising monitoring a change of the neutrino emission source or neutrino emission source components; wherein the monitoring comprises recognizing a change in parts of the event energy spectrum CS that are characteristic for neutrino- nucleus-scattering events.

[0378] (30) A geological-radiochemical sensing method, the method comprising: Position a neutrino detection device 400 at a first position and measure a first neutrino-nucleus-scattering event rate; position the neutrino detection device 400 at a second position and measure a second neutrino- nucleus-scattering event rate; and triangulate, based on the first neutrino-nucleus -scattering event rate and the second neutrino-nucleus-scattering event rate, a position of a neutrino emitter; wherein the neutrino detection device 400 is the neutrino detection device 400 according to any one of (1) to (25).

[0379] (31) The sensing method according to (30), further comprising: position a neutrino detection device 400 at a plurality of positions and measure a neutrino emission source abundance; calculate, based on the measured neutrino emission source abundances, a distribution of neutrino emission sources; wherein the neutrino detection device 400 is the neutrino detection device 400 according to any one of (1) to (25).

[0380] (32) A telecommunication method, comprising generating a neutrino transmission 512 using a controlled neutrino source 503; and detecting the neutrino transmission 512 using the neutrino detection device 400 according to any one of (1) to (25). LIST OF REFERENCE SIGNS

[0381] 11 incident neutrino

[0382] 12 scattered neutrino

[0383] 20 free charges

[0384] 23 charge flow

[0385] 25 Ge-nucleus

[0386] 100 semiconductor diode

[0387] 101 radiation detection unit

[0388] 131 read-out electrode

[0389] 132 target

[0390] 133 read-out electronics

[0391] 200 cryostat device

[0392] 220 cooling rod

[0393] 230 cryostat arm

[0394] 235 signal transmission line

[0395] 240 cryogenic temperature generator

[0396] 310 high-voltage input

[0397] 311 outer region of the semiconductor diode

[0398] 320 high -power voltage supply

[0399] 330 the low power voltage supply

[0400] 400 neutrino detection device

[0401] 401 cavity

[0402] 410 airborne radiation shield system

[0403] 411 pipe

[0404] 420 low-density material layer

[0405] 430 low-density material layer

[0406] 440 anticoincidence veto system 441 scintillation device

[0407] 450 power generator

[0408] 460 data acquisition unit

[0409] 470 control unit

[0410] 500 nuclear reactor

[0411] 501 fuel rods

[0412] 502 raw material resource

[0413] 503 controlled neutrino source

[0414] 510 neutrino flux

[0415] 511 geological neutrinos

[0416] 512 neutrino transmission

[0417] 520 restricted area protection

[0418] 521 Earth’s crust

[0419] 522 solid body

[0420] 600 vehicle

[0421] CS event energy spectrum

[0422] CN1 neutrino event energy spectrum

[0423] CN2 neutrino event energy spectrum

[0424] CB background spectrum

[0425] G gradient

Claims

CLAIMS1. A neutrino detection device (400), comprising: a radiation detection unit (101) comprising a semiconductor diode (100) configured to act as both target (132) and sensor, and read-out electronics (133) comprising a read-out electrode (131) configured to sense free charges (20) generated in the target (132), wherein the read-out electronics (133) is configured to generate, based on the free charges (20), sensor signals; and a data acquisition unit (460) configured to identify, based on the sensor signals, neutrino- nucleus-scattering events.

2. The device (400) according to claim 1, wherein the data acquisition unit (460) is configured to determine an event energy spectrum (CS) based on the sensor signals, and to determine neutrino- nucleus-scattering events based on the event energy spectrum (CS).

3. The device (400) according to claim 2, wherein the data acquisition unit (460) is configured to identify the neutrino-nucleus -scattering events based on an increase of the event energy spectrum (CS).

4. The device (400) according to any one of claims 2 to 3, wherein the data acquisition unit (460) is configured to identify the neutrino-nucleus-scattering events based on an increase of the event energy spectrum (CS) as compared to a predefined nominal event energy spectrum (CB).

5. The device (400) according to claim 4, wherein the nominal event energy spectrum (CB) is a prestored spectrum that has been determined in a background measurement process conducted in absence of a neutrino source in a vicinity of the detector (400).

6. The device (400) according to any one of claims 2 to 5, wherein the data acquisition unit (460) is configured to determine the neutrino-nucleus-scattering events based on the event energy spectrum (CS) at energies that are indicative of neutrino-nucleus-scattering events.

7. The device (400) according to claim 6, wherein energies that are indicative of neutrino-nucleus- scattering events are energies of 1000 eV or less.

8. The device (400) according to any one of claims 2 to 7, wherein a low energy detection threshold of less than 200 eV is achieved by comprising a very low noise radiation detection unit and a very low noise read-out electronics; and by a data acquisition system able to reconstruct sensor signal energies lower than 200 eV.

9. The device (400) according to any one of claims 2 to 8, wherein identifying the neutrino- nucleus-scattering events comprises determining a shape and a gradient of the event energy spectrum (CS).

10. The device (400) according to any one of claims 2 to 9, wherein identifying the neutrino- nucleus-scattering events comprises determining an integrated count rate (A) of the event energy spectrum (CS).

11. The device (400) according to any one of claims 2 to 10, wherein the data acquisition system is further configured to recognize, based on the event energy spectrum (CS), a neutrino emission source and neutrino emission source components.

12. The device (400) according to claim 11, wherein the neutrino emission source is recognized based on the shape or gradient (G) of the event energy spectrum (CS), or based on the integral count rate (A) of the event energy spectrum (CS).

13. The device (400) according to any one of claims 1 to 12, wherein the semiconductor diode (100) is configured as a p-n junction and operated with a reverse bias voltage.

14. The device (400) according to any one of claims 1 to 13, wherein the semiconductor diode(100) is a semiconductor high-purity germanium diode (100) and the read-out electronics (133) is a very low noise read-out electronics (133) and the read-out electrode (131) is a point-like read-out electrode (131).

15. The device (400) according to any one of claims 1 to 14, further comprising a cryocooling device (200), configured to perform cryocooling of the device (400).

16. The device (400) according to any one of claims 1 to 15, wherein the radiation detection unit(101) is operated at a temperature of less than 100 K.

17. The device (400) according to claim 15 or 16, wherein the cryocooling device (200) comprises a cryogenic temperature generator (240); and a cryostat system; wherein the cryostat system connects the radiation detection unit (101) to the cryogenic temperature generator (240), such that the cryogenic temperature generator (240) can be used to perform cooling of the radiation detection unit (101).

18. The device (400) according to any one of claims 1 to 17, further comprising a multilayer radiation shield that shields the radiation detection unit (101) against background radiation, wherein the radiation detection unit (101) is housed in the multilayer radiation shield.

19. The device (400) according to claim 18, wherein the multilayer radiation shield comprises one or more high-density material layers (420), wherein the high-density material layer (420)comprises a high-density material, the high-density material further having a low amount of intrinsic self-radiation.

20. The device (400) according to any one of claims 18 to 19, wherein the multilayer radiation shield comprises one or more low-density material layers (430), wherein the low-density material layer (430) comprises a low-density material, the low-density material further having material properties providing a high neutron moderation capability and / or a high neutron capture capability.

21. The device (400) according to any one of claims 18 to 20, wherein the low-density material is a mixture of materials.

22. The device (400) according to any one of claims 18 to 21, wherein the multilayer radiation shield comprises an airborne radiation shield system (410), which suppresses airborne radiation penetrating the multilayer radiation shield by providing, in an interior of the multilayer radiation shield (401), an atmosphere with low intrinsic radioactivity.

23. The device (400) according to any one of claims 19 to 22, wherein the multilayer radiation shield comprises an anticoincidence veto system (440) configured to detect incident cosmic radiation, and to generate a veto signal with a predetermined veto interval following a detection of incident cosmic radiation, and to transmit the veto signal to the data acquisition system (460).

24. The device (400) according to any one of claims 18 to 23, wherein the data acquisition system (460) is further configured to reject, based on reception of the veto signal, sensor signals during the veto interval.

25. The device (400) according to any one of claims 17 to 24, comprising a plurality of the radiation detection unit (101); and a plurality of the read-out electronics (133); and one or more of the data acquisition systems (460), wherein one each of the data acquisition system (460) analyzes the sensor signals from at least one of the radiation detection units (101); a plurality of the cryocooling devices (200), wherein each one of the radiation detection units (101) is housed in one each of the cryostat systems; and one multilayer radiation shield surrounding the cryostat systems.

26. A vehicle (600), comprising the device (400) according to any one of claims 1 to 25.

27. A neutrino detection method, comprising: sense free charges (20) generated in a target (132), generate, based on the sensed free charges (20), a sensor signal, and identify, based on a plurality of the sensor signals and the reconstructed event energy spectrum (CS), neutrino-nucleus -scattering events.

28. A reactor monitoring method, the method comprising:measure with a device (400) according to any one of claims 1 to 25 located at a detector position a plurality of neutrino-nucleus-scattering events during a monitoring period and recognize, based on the neutrino-nucleus-scattering events, a reactor neutrino emission source and changes in the reactor fuel composition in a given reactor.

29. The monitoring method according to claim 28, further comprising monitoring a change of the neutrino emission source or neutrino emission source components; wherein the monitoring comprises recognizing a change in parts of the event energy spectrum (CS) that are characteristic for neutrino-nucleus-scattering events.

30. A geological-radiochemical sensing method, the method comprising: position a neutrino detection device (400) at a first position and measure a first neutrino- nucleus-scattering event rate; position the neutrino detection device (400) at a second position and measure a second neutrino-nucleus-scattering event rate; and triangulate, based on the first neutrino- nucleus-scattering event rate and the second neutrino-nucleus-scattering event rate, a position of a neutrino emitter; wherein the neutrino detection device (400) is the neutrino detection device (400) according to any one of claims 1 to 25.

31. The sensing method according to claim 30, further comprising: position a neutrino detection device (400) at a plurality of positions and measure a neutrino emission source abundance; calculate, based on the measured neutrino emission source abundances, a distribution of neutrino emission sources; wherein the neutrino detection device (400) is the neutrino detection device (400) according to any one of claims 1 to 25.

32. A telecommunication method, comprising generating a neutrino transmission (512) using a controlled neutrino source (503); and detecting the neutrino transmission (512) using the neutrino detection device (400) according to any one of claims 1 to 25.

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