NV-diamond based radiation dose rate sensor

Abstract

A florescent radiation dose rate sensor includes a nitrogen-vacancy diamond; a light detection system having a photon detection element and an optical filter, and wherein the light detection system is configured to receive light, filter the light, and detect photon flux of the light; and an optical assembly configured to deliver excitation light to and collect scattered florescent light from the NV diamond and configured to optically couple the NV diamond to the light detection system.

Description

[0001] NV-DIAMOND BASED RADIATION DOSE RATE SENSOR

[0002] Related Applications

[0003] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 683,468 (filed August 15, 2024), which is herein incorporated by reference in its entirety.

[0004] Federally-Sponsored Research and Development

[0005] This invention was made with United States Government support from the National Institute of Standards and Technology (NIST), an agency of the United States Department of Commerce. The Government has certain rights in this invention.

[0006] Copyright Notice

[0007] This patent disclosure may contain material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the U.S. Patent and Trademark Office patent file or records but, otherwise reserves any and all copyright rights.

[0008] Field of Invention

[0009] The present invention relates generally to radiation dosimeters, and more particularly to a nitrogen-vacancy-based dosimeter.

[0010] Background

[0011] A radiation dosimeter allows direct, in situ measurement of molecular damage within irradiated cells, and makes it traceable to national standards. The technology provides a metrological foundation for relative biological effectiveness (RBE) of ionizing radiation, needed to define absorbed dose for biological organisms and a key quantity for prescribing doses for killing tumors and pathogens and for sterilizing food and medical equipment.

[0012] Radiation is used in industry and medicine for an enormous variety of purposes that range from the processing of materials to sterilization of food to medical radiotherapy. It is thus remarkable that we have come to rely on a single quantity - absorbed dose, or energy absorbed per unit mass - to quantify radiation delivery for any prescribed scenario irrespective of beam type or target. When the target is a patient undergoing radiotherapy, the current definition of absorbed dose must be supplemented by a weighting factor, RBE, whose dependence on type of radiation and cellular composition defies existing metrology, forcing clinicians to construct estimates based on histological studies and computational models. Uncertainties of 50% or more resulting from such methods in estimating RBE near critical structures (e.g., spinal cord, retina) severely restrict the potential benefits of cutting-edge proton- or ion-beam radiotherapy.

[0013] Nitrogen-vacancy (NV) centers in diamond are reliable single-photon emitters, with applications in quantum technologies and metrology. Two charge states are known for NV centers, NV!0)and NV^, with the states having a long electron spin coherence time.

[0014] Summary of Invention

[0015] Presented is a photonic device comprising a diamond with color center defect, specifically a nitrogen vacancy, whose optical properties (such as integrated florescent intensity, band shape, relative intensities of component modes and electronic energy levels) change in a predictable way in response to the interaction of radiation with the sensor and / or its surroundings. Exemplary embodiments can be used to determine, in real time, the rate of radiation impingement on the sensor, locally. Such devices can be used to determine localized effects of absorbed radiation on the surrounding matrix e.g. cells.

[0016] According to an aspect of the invention, a florescent radiation dose rate sensor includes a nitrogen-vacancy diamond; a light detection system having a photon detection element and an optical filter, and wherein the light detection system is configured to receive light, filter the light, and detect photon flux of the light; and an optical assembly configured to deliver excitation light to and collect scattered florescent light from the NV diamond and configured to optically couple the NV diamond to the light detection system.

[0017] Optionally, the optical assembly includes a quartz light pipe physically and optically coupled to the NV diamond. Optionally, the optical assembly includes a wide band circulator physically and optically coupled to the NV diamond.

[0018] Optionally, the photon detection element includes a photodetector.

[0019] Optionally, the photon detection element includes a single photon detector.

[0020] Optionally, the photon detection element includes a charge coupled device.

[0021] Optionally, the photon detection element includes an avalanche photodiode.

[0022] Optionally, the photon detection element includes a CMOS device.

[0023] Optionally, the optical filter is configured to remove excitation light and ambient room light at wavelengths longer than 800 nm.

[0024] Optionally, the optical filter includes one or more notch filters.

[0025] Optionally, the optical filter includes a grating configured to spatially spread out the light.

[0026] Optionally, the grating is angled such that only light between 570 nm and 800 nm is incident on the photon detection element.

[0027] Optionally, the florescent radiation dose rate sensor includes a digitizer configured to digitize an electrical signal of the photon detection element and a processor configured to process and / or store the digitized electrical signal of the photon detection element.

[0028] According to another aspect of the invention, a method of sensing a radiation dose rate includes exposing an NV diamond to radiation; collecting light from the NV diamond; identifying changes in spectral shape and intensity; and inferring radiation dose rate from the identified changes due to excess energy provided by Compton electrons changing charge state distribution of a nitrogenvacancy color center of the NV diamond.

[0029] Optionally, the method includes the step of exposing the NV diamond to light.

[0030] Optionally, the light the NV diamond is exposed to is green light.

[0031] Optionally, the method includes the step of analyzing a total integrated intensity of light from the NV diamond.

[0032] Optionally, the method includes the step of analyzing light from the NV diamond between 550 and 800 nm. Optionally, the method includes the step of fitting light data from the NV diamond to a gaussian.

[0033] Optionally, the method includes the step of using dimensionality reduction to analyze the light from the NV diamond.

[0034] The foregoing and other features of the invention are hereinafter described in greater detail with reference to the accompanying drawings.

[0035] Brief Description of the Drawings

[0036] FIG. 1 shows an exemplary embodiment where NV diamond is coupled to quartz light pipe.

[0037] FIG. 2 shows an all-optical fiber embodiment.

[0038] FIG. 3 shows difference spectra.

[0039] FIG. 4 shows a graph of temperature dependence of the spectra as measured by plotting the Debye-Waller Factor (DWF).

[0040] FIG. 5, shows a graph of temperature dependence of the spectra as measured by plotting the Debye-Waller Factor (DWF) when the integration area is expanded beyond the second phonon.

[0041] FIG. 6 shows, at top, difference spectra between spectra taken with 100 keV beam energy at 100 microamp and 1 milliAmp beam current. The difference spectra shows increased spectral contribution in the NV( )range at higher beam currents. At bottom, FIG. 6 shows, at 1 milliAmp beam current when beam energy is increased from 100 keV to 200 keV and 300 keV, the spectral contribution from the NV':0)region increase while the NV( )phonon side band region decrease.

[0042] FIG. 7 shows, on the left, representative spectra of NV diamond under increasing beam current with laser off. At right, FIG. 7 shows top three PCA modes for NV under irradiation without laser excitation are shown. Spectral profile of these modes indicates the cathodoluminescent spectra of NV is dominated by NV(0)state and spectral intensity changes in the NV(0)and NV( )state are inversely correlated.

[0043] FIG. 8 shows an exemplary method of sensing a radiation dose rate.

[0044] FIG. 9 shows an exemplary computer for use in an exemplary dose rate sensor. Detailed Description

[0045] An exemplary florescent radiation dose rate sensor includes a florescent signal that changes in response to the presence of radiation due to excess energy provided by Compton electrons changing the charge state distribution of the nitrogen-vacancy (NV) color center. Change in the color center mostly visibly impacts the spectral profile in the region dominated by NV negative state, NVH. Small changes are also observed in the region dominated by NV zero state, NV(0). These relative changes are correlated with dose rate.

[0046] Exemplary embodiments allow measurement of localized rate of radiation absorption over real-time (sub mm scales and sub millisecond time scales) giving access to time and space variability of the radiation field. Current national standards are built to work on the assumption of time and space uniformity and hence are ill-suited for modem radio-therapy schemes that employ short, high dose pulses to target narrow regions of interest.

[0047] Referring first to FIG. 1 and 2, shown are exemplary florescent radiation dose rate sensor 100, 200 where an NV diamond is coupled to a quartz light pipe. All optical parts, including the NV diamond may be commercially available.

[0048] The florescent radiation dose rate sensor 100 includes an NV diamond 110 and an optical assembly (e.g., lightpipe or fiber optic assembly) 120 configured to deliver excitation light and collect scattered florescent light. Diamond 110 may be fixed to the fiber optic assembly 120 by, e.g., optically clear epoxy. In the case of lightpipe 122, florescent light maybe coupled into a fiber optic 124 to be carried to a light detection system 130 via a lens 126 or objective.

[0049] The light detection system 130 is configured to receive light, filter the light, and detect the photon flux. Given low signal levels compared to ambient light, it is advantageous to house the photon detection element 132 (be it a photodetector, avalanche photodiode, single photon detector, charge coupled device or CMOS device, e.g.) in a dark enclosure 134. To permit the signal light inside the enclosure, an aperture 136 may be provided. The aperture 136 may include a fiber optic coupler 138 that holds the fiber optic 124 in place. This allows for alignment of an end of the optical fiber 124 with the aperture and other optical elements, such as an optional optical filter 139, inside the enclosure. Inside the optical enclosure incoming light may be filtered by filter 139 to remove the excitation light and ambient room light at wavelengths longer than 800 nm. This may be accomplished using notch filters and / or a grating that spatially spread out the light. In case of grating, it is angled such that only light in the 570 nm to 800 nm is incident on the detection element. It is noted that notch filters could be placed outside the spectrometer; i.e. an embodiment could go from fiber optic to notch filters, back into an optical fiber and then to the detection apparatus.

[0050] Regarding FIG. 1 , the excitation light 105 is propagated through free- space (and passes through an optional optical element such as a lens or objective 106) and illuminates the diamond. Scattered light, excitation photons and florescence photons are coupled into the lightpipe. Guided photons are coupled into a fiber optic that carries the light away from the radiation area the detection system. The detection system shown comprises an aperture for admitting scattered light into the detection system, notch filter(s) that remove light shorter than 632 nm and longer than 800 nm. The filtered light is passed onto a detector which converts the light into electrical signal. This signal is digitized by digitizer 140 and either processed or stored for future analysis by processor 150.

[0051] Turning now to Fig. 2, an exemplary embodiment of the florescent radiation dose rate sensor is shown at 200. The exemplary florescent radiation dose rate sensor 200 is substantially the same as the above-referenced exemplary florescent radiation dose rate sensor 100, and consequently the same reference numerals but indexed by 100 are used to denote structures corresponding to similar structures in the florescent radiation dose rate sensors. In addition, the foregoing description of the florescent radiation dose rate sensor 100 is equally applicable to the florescent radiation dose rate sensor 200 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the florescent radiation dose rate sensors may be substituted for one another or used in conjunction with one another where applicable.

[0052] FIG 2 shows an all-optical fiber embodiment. Here the excitation light and scattered light are carried to and from the diamond sample using either a bundle of optical fibers or single optical fiber 222 as part of optical device called a wide band circulator 220. When using a fiber optic bundle, the diamond 210 is affixed to one end of the optical fiber 222 carrying light from the laser while the other end is connected to a laser 205 that produces green light. Scattered light is coupled in the optical fiber(s) 224 that carry the light to the detection system. In the case a wide band circulator is used, the diamond is affixed to the port 2 of the device that while port 1 is connected to light source i.e. laser. The backscattered light travels down port 2 and is transferred to fiber that delivers it to port 3 i.e. connected to the detection system.

[0053] The detection system shown comprises an aperture 236 for admitting scattered light into the detection system. Admitted light is then filtered using optical filters 239 such as, e.g., notch filter(s) and / or grating spectrometer. Notch filter(s) remove light shorter than 632 nm and longer than 800 nm. Grating spectrometer disperses the different wavelengths of light in space, illuminating a detector 232 such as a charge coupled device (CCD). The CCD captures the spatial light intensity distribution by converting the optical signal into electrical signal. This signal, photoluminescence spectra, is digitized by digitizer 240 and analyzed or stored for future analysis by processor 250.

[0054] Exemplary diamonds may be any commercially available diamond with the appropriate defect as discussed above.

[0055] To incorporate the diamond into the photonic device, one may place a lightpipe or fiber optic so an end face points up and is running parallel to the ground. Place the diamond sample on the flat end face of the fiber optic. To ensure the diamond is correctly placed on the fiber / lightpipe, illuminate the diamond sample with green light. Laser safety googles appropriate for green laser light, will filter the green light and the sample, if correctly illuminated, will appear red. Similarly, faint red light will appear on the other end of the lightpipe or fiber optic. This light can be detected visually with the aid laser safety googles and / or an exemplary detection system.

[0056] Once the diamond is appropriately aligned. Using a narrow-gauge syringe deliver 1 microliter aliquots of optically clear epoxy to affix the diamond to the lightpipe / optical fiber. Cure the epoxy until it hardens.

[0057] Compton electrons resulting from radiation’s interaction with materials, including diamond lattice, may interact with the NV sites resulting in changes in NV’s charge state that can be read-off as integrated intensity changes. Under pulsed X-ray illumination, total florescence intensity at the detector shows a proportional change.

[0058] Referring now to FIG. 3, which shows difference spectra, excess energy from the Compton electrons is deposited into the diamond lattice. This energy then drives the transition between the neutral and charged NV states (NV(0)and NV^). The red florescence photons between 632 nm and 800 nm overwhelmingly originates from the NV( )state. Any change in the relative population of the NV( )state results in proportional changes in observed integrated intensity. Furthermore, when observing the wavelength-resolved spectra, changes in NV( )population proportionally impact the relative intensity of the 637 nm zero phonon line intensity. Changes in the phonon side band at wavelengths above the ZPL (« 642 nm to 800 nm) signal changes in the covalent bonds surrounding the NV color center resulting in alteration of NV energy levels. The first two phonons are semi-localized vibrations or collective motions of the nitrogen atom and its adjacent carbons. The broader phonon side band contains motional contributions from carbons located further away from the nitrogen in addition to the nearby carbons.

[0059] Referring now to FIG. 4, temperature dependence of the spectra as measured by plotting the Debye-Waller Factor (DWF) shows the expected linear behavior, expect at the lowest temp. The temperature dependence shows a large, statistically significant offset between in-radiation and radiation-free measurements.

[0060] Referring now to FIG. 5, when the integration area is expanded beyond the second phonon, the temperature dependence no longer appears to be linear. This result clearly indicates changes in the phonon continuum are taking place when the sample is exposed to radiation.

[0061] Turning now to FIG. 6, NV diamond with relatively high NV(0)population spectral dependence on radiation dose has shown that increasing beam intensity at low beam energy leads to an increase in spectral intensity in the NV( )region while the NV(0)region remains unperturbed. Increasing beam energy at constant beam intensity results in increase in spectral energy in the NV(0)region and a decrease in the NV( )region. By relatively high and relatively low NV(0), we mean the ratio of NV(0) / NV( )is about 0.44 and 0.04, respectively. Turning now to FIG. 7, with the laser off, radiation exposure causes the NV diamond sample to emit cathodoluminescence whose spectral intensity is directly proportional to beam intensity. Analysis shows that:

[0062] • The top 3 PCA modes indicate a component that results in proportional increase spectral intensity with beam intensity.

[0063] • A shift in spectral intensity from the NV( )phonon side band (PSB) region to NV(0)PSB and regions to the blue of NV(0)ZPL.

[0064] • Third mode captures a general decrease in the two NV charge state spectral signatures.

[0065] Turning now to FIG. 8, shown is an exemplary method of sensing a radiation dose rate at 800. Optionally, at block 810, the NV diamond is exposed to light (e.g., green light), making response from the diamond easier to determine at low intensities. At block 820, an NV diamond is exposed to radiation. At block 830, light is collected from the NV diamond. At block 840, changes in spectral shape and intensity of the light are determined. At block 850, radiation dose rate is inferred from the identified changes due to excess energy provided by Compton electrons changing charge state distribution of a nitrogen-vacancy color center of the NV diamond.

[0066] Total integrated intensity of light from the NV diamond may be calculated and used to infer radiation dose rate. In particular, light from the NV diamond between 550 and 800 nm may, preferably, be used. The gathered light data may be fitted to a gaussian for analysis. In exemplary embodiments, machine learning / AI techniques and / or dimensionality reduction may be used to analyze changes in spectral shape and intensity to infer radiation dose rate.

[0067] It should be understood that the calculations may be performed by any suitable computer system, such as that diagrammatically shown in FIG. 9. Data is entered into system 900 via any suitable type of user interface 916, and may be stored in memory 912, which may be any suitable type of computer readable and programmable memory and is preferably a non-transitory, computer readable storage medium. Calculations are performed by processor 914, which may be any suitable type of computer processor and may be displayed to the user on display 918, which may be any suitable type of computer display. Processor 914 may be associated with, or incorporated into, any suitable type of computing device, for example, a personal computer or a programmable logic controller. The display 918, the processor 914, the memory 912 and any associated computer readable recording media are in communication with one another by any suitable type of data bus, as is well known in the art.

[0068] Examples of computer-readable recording media include non-transitory storage media, a magnetic recording apparatus, an optical disk, a magnetooptical disk, and / or a semiconductor memory (for example, RAM, ROM, etc.). Examples of magnetic recording apparatus that may be used in addition to memory 912, or in place of memory 912, include a hard disk device (HDD), a flexible disk (FD), and a magnetic tape (MT). Examples of the optical disk include a DVD (Digital Versatile Disc), a DVD-RAM, a CD-ROM (Compact Disc- Read Only Memory), and a CD-R (Recordable)ZRW. It should be understood that non-transitory computer-readable media include all computer-readable media except for a transitory, propagating signal.

[0069] The processes described herein may be embodied in, and fully automated via, software code modules executed by a computing system that includes one or more general purpose computers or processors. The code modules may be stored in any type of non-transitory computer-readable medium or other computer storage device. Some or all the methods may alternatively be embodied in specialized computer hardware. In addition, the components referred to herein may be implemented in hardware, software, firmware, or a combination thereof.

[0070] Many other variations than those described herein will be apparent from this disclosure. For example, depending on the embodiment, certain acts, events, or functions of any of the algorithms described herein can be performed in a different sequence, can be added, merged, or left out altogether (e.g., not all described acts or events are necessary for the practice of the algorithms). Moreover, in certain embodiments, acts or events can be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or multiple processors or processor cores or on other parallel architectures, rather than sequentially. In addition, different tasks or processes can be performed by different machines and / or computing systems that can function together.

[0071] Any logical blocks, modules, and algorithm elements described or used in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, and elements have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. The described functionality can be implemented in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the disclosure.

[0072] The various illustrative logical blocks and modules described or used in connection with the embodiments disclosed herein can be implemented or performed by a machine, such as a processing unit or processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor can be a microprocessor, but in the alternative, the processor can be a controller, microcontroller, or state machine, combinations of the same, or the like. A processor can include electrical circuitry configured to process computerexecutable instructions. In another embodiment, a processor includes an FPGA or other programmable device that performs logic operations without processing computer-executable instructions. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Although described herein primarily with respect to digital technology, a processor may also include primarily analog components. For example, some or all of the signal processing algorithms described herein may be implemented in analog circuitry or mixed analog and digital circuitry. A computing environment can include any type of computer system, including, but not limited to, a computer system based on a microprocessor, a mainframe computer, a digital signal processor, a portable computing device, a device controller, or a computational engine within an appliance, to name a few.

[0073] The elements of a method, process, or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module stored in one or more memory devices and executed by one or more processors, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of non-transitory computer-readable storage medium, media, or physical computer storage known in the art. An example storage medium can be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The storage medium can be volatile or nonvolatile.

[0074] While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation. Embodiments herein can be used independently or can be combined.

[0075] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The ranges are continuous and thus contain every value and subset thereof in the range. Unless otherwise stated or contextually inapplicable, all percentages, when expressing a quantity, are weight percentages. The suffix (s) as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including at least one of that term (e.g., the colorant(s) includes at least one colorants). Option, optional, or optionally means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event occurs and instances where it does not. As used herein, combination is inclusive of blends, mixtures, alloys, reaction products, collection of elements, and the like.

[0076] As used herein, a combination thereof refers to a combination comprising at least one of the named constituents, components, compounds, or elements, optionally together with one or more of the same class of constituents, components, compounds, or elements.

[0077] All references are incorporated herein by reference.

[0078] The use of the terms “a,” “an,” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. It can further be noted that the terms first, second, primary, secondary, and the like herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. It will also be understood that, although the terms first, second, etc. are, in some instances, used herein to describe various elements, these elements should not be limited by these terms. For example, a first current could be termed a second current, and, similarly, a second current could be termed a first current, without departing from the scope of the various described embodiments. The first current and the second current are both currents, but they are not the same condition unless explicitly stated as such.

[0079] The modifier about used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity). The conjunction or is used to link objects of a list or alternatives and is not disjunctive; rather the elements can be used separately or can be combined together under appropriate circumstances.

[0080] Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.

Claims

ClaimsWhat is claimed is:1 . A florescent radiation dose rate sensor comprising: an NV diamond; a light detection system having a photon detection element and an optical filter, and wherein the light detection system is configured to receive light, filter the light, and detect photon flux of the light; and an optical assembly configured to deliver excitation light to and collect scattered florescent light from the NV diamond and configured to optically couple the NV diamond to the light detection system.

2. The florescent radiation dose rate sensor of claim 1 , wherein the optical assembly includes a quartz light pipe physically and optically coupled to the NV diamond.

3. The florescent radiation dose rate sensor of claim 1 , wherein the optical assembly includes a wide band circulator physically and optically coupled to the NV diamond.

4. The florescent radiation dose rate sensor of claim 1 , wherein the photon detection element includes a photodetector.

5. The florescent radiation dose rate sensor of claim 1 , wherein the photon detection element includes a single photon detector.

6. The florescent radiation dose rate sensor of claim 1 , wherein the photon detection element includes a charge coupled device.

7. The florescent radiation dose rate sensor of claim 1 , wherein the photon detection element includes an avalanche photodiode.

8. The florescent radiation dose rate sensor of claim 1 , wherein the photon detection element includes a CMOS device.

9. The florescent radiation dose rate sensor of claim 1 , wherein the optical filter is configured to remove excitation light and ambient room light at wavelengths longer than 800 nm.

10. The florescent radiation dose rate sensor of claim 1 , wherein the optical filter includes one or more notch filters.11 . The florescent radiation dose rate sensor of claim 1 , wherein the optical filter includes a grating configured to spatially spread out the light.

12. The florescent radiation dose rate sensor of claim 1 , wherein the grating is angled such that only light between 570 nm and 800 nm is incident on the photon detection element.

13. The florescent radiation dose rate sensor of claim 1 , further comprising a digitizer configured to digitize an electrical signal of the photon detection element and a processor configured to process and / or store the digitized electrical signal of the photon detection element.

14. A method of sensing a radiation dose rate, the method comprising the steps of: exposing an NV diamond to radiation; collecting light from the NV diamond; identifying changes in spectral shape and intensity; and inferring radiation dose rate from the identified changes due to excess energy provided by Compton electrons changing charge state distribution of a nitrogen-vacancy color center of the NV diamond.

15. The method of claim 14, further comprising the step of: exposing the NV diamond to light.

16. The method of claim 15, wherein the light the NV diamond is exposed to is green light.

17. The method of claim 14, further comprising the step of analyzing a total integrated intensity of light from the NV diamond.

18. The method of claim 14, further comprising the step of analyzing light from the NV diamond between 550 and 800 nm.

19. The method of claim 14, further comprising the step of fitting light data from the NV diamond to a gaussian.

20. The method of claim 14, further comprising the step of using dimensionality reduction to analyze the light from the NV diamond.

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