Lightweight solar high-energy radiation spectrometer

Abstract

The invention discloses a light-weight solar high-energy radiation spectrometer, which belongs to the technical field of solar physical and space observation and comprises a scintillator detector. The scintillator detector comprises a plurality of crystal layers which are stacked front and back, and each crystal layer comprises one or more crystals which are arranged side by side. The crystal comprises a CeBr3 crystal and an LYSO crystal, and the CeBr3 crystal is located on the front side of the LYSO crystal; the two ends of each crystal are respectively provided with a photomultiplier and a silicon photomultiplier, and signals read from the two ends are fused. The invention aims to carry out accurate energy spectrum observation on high-energy photons in an energy range of 100keV to 20MeV, the energy range covers characteristic gamma rays generated when solar flares burst, and an important tool is provided for in-depth research on solar activity. The total weight of the whole spectrometer is controlled within 30 kg, the scintillation crystal part used for energy detection is about 15 kg, and under the condition that the weight and the size are limited, the spectrometer gives consideration to the high-resolution measurement capability of high-energy photons and meets the strict requirements of the deep space environment.

Description

Technical Field

[0001] The invention belongs to the field of solar physics and space observation technology, relates to a deep space detection device, and in particular to a lightweight solar high-energy radiation spectrometer. Background Art

[0002] In recent years, multi-angle stereoscopic observation of the sun has gradually become an important development direction for solar space observation, and the demand for stereoscopic and multi-angle observation of the sun has become more urgent. Solar activity has a significant impact on the Earth's space weather. Events such as solar flares and coronal mass ejections have a significant impact on the Earth's ionosphere, electromagnetic environment, and the safety of spacecraft operations. Therefore, multi-angle observation of solar activity can not only improve our understanding of solar activity, but also enhance the ability to predict space weather.

[0003] In order to achieve stereoscopic observation, in addition to the Earth's perspective, deep space observations are also needed to provide multi-angle joint observations. However, since deep space exploration missions are often limited by launch costs, mission timing, system complexity, and payload weight and power consumption requirements, the weight of a single payload faces extremely strict restrictions. Therefore, the development of a solar high-energy radiation spectrometer that can effectively detect high-energy photons with a weight of less than 30kg has significant scientific and technological significance. The weight limit in deep space exploration mainly comes from the launch cost and the carrying capacity of the satellite platform; under this limitation, the design of a spectrometer that can combine detection efficiency, detection accuracy and detection reliability is a challenging research direction. Summary of the invention

[0004] The present invention provides a lightweight solar high-energy radiation spectrometer to overcome the defects of the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A lightweight solar high-energy radiation spectrometer includes a scintillator detector; the scintillator detector includes a plurality of crystal layers stacked front to back, the crystal layers include one or more crystals arranged side by side; the crystals include CeBr3 crystals and LYSO crystals, the CeBr3 crystals are located in front of the LYSO crystals; a photomultiplier tube (PMT) and a silicon photomultiplier tube (SiPM) are respectively arranged at both ends of each crystal, and the signals read out at both ends are fused.

[0007] Through the stacked structure design, it provides efficient energy spectrum detection for high-energy photons from 100keV to 20MeV. Specifically, CeBr3 crystal has high energy resolution and low background characteristics, which is suitable for accurate detection of keV-level photons; LYSO crystal has high density, large atomic number, and high light yield, which is suitable for detection of MeV-level photons. The CeBr3 crystal on the front side is used to improve the resolution of low-energy photons, and the LYSO crystal on the back side is used to improve the detection efficiency of high-energy photons. The double-end readout of the CeBr3 crystal on the front side and the LYSO crystal on the back side can improve the energy resolution and detection efficiency of photons in different energy ranges. At the same time, PMT and SiPM are set at both ends of each crystal for double-end readout: the PMT end is used to improve the gain and maintain excellent detection performance for low-intensity signals, and the SiPM end enhances the ability to resist magnetic fields and improves the output linearity of high-energy photons. The two are backed up by each other, thereby improving the stability and reliability of the instrument. In addition, the total weight of the spectrometer does not exceed 30kg, of which the weight of the scintillation crystal part is controlled within 15kg.

[0008] To optimize the above technical solutions, the specific measures taken also include:

[0009] Furthermore, the number of layers of CeBr3 crystal is two, and the number of layers of LYSO crystal is at least one. The overall layout of the crystal stacking structure can be adjusted according to the requirements of deep space observation missions. When the demand for high-energy detection is high, additional LYSO layers can be added and a dual-end readout method can be used to further improve the detection efficiency and time resolution.

[0010] Furthermore, the crystal layer includes two crystals arranged side by side to enhance the detection efficiency of high-energy photons, and the crystal size is 10.16cm×5.3cm×5.3cm.

[0011] Furthermore, the signals read out from both ends of each crystal are pre-amplified, filtered and digitized before being fused.

[0012] Furthermore, it also includes an anti-coincidence detector; the anti-coincidence detector includes a plastic scintillator (PSD) arranged on the front side and the upper side of the scintillator detector, which is used for anti-coincidence detection to eliminate the interference of high-energy charged particles.

[0013] Furthermore, a photomultiplier tube is disposed at the end of the plastic scintillator and is installed on the same side as the photomultiplier tube of the scintillator detector.

[0014] Furthermore, it also includes a front-end electronics system; the front-end electronics system includes a signal amplification, filtering and digitization module, which performs pre-amplification, filtering and digitization on the signals read out by each photomultiplier tube and silicon photomultiplier tube.

[0015] Furthermore, it also includes a high-speed signal acquisition system; the photomultiplier tubes and silicon photomultiplier tubes at both ends of the crystal are respectively connected in parallel to the high-speed signal acquisition system through the front-end electronics system; the photomultiplier tubes of the plastic scintillator are also connected to the high-speed signal acquisition system through the front-end electronics system; the high-speed signal acquisition system collects and processes the signals read out by each photomultiplier tube and silicon photomultiplier tube, and provides a trigger signal.

[0016] The trigger signal is used to synchronize data acquisition, and ensure that the acquired data corresponds to the same event by coordinating the acquisition time of each channel. In addition, the trigger signal can also be used for event recognition to filter out charged particles and gamma photons.

[0017] Furthermore, the high-speed signal acquisition system fuses the signals of the photomultiplier tubes and silicon photomultiplier tubes at both ends of the crystal, and determines the effective event according to the trigger logic and the anti-coincidence detection result, thereby realizing high-precision energy spectrum measurement of keV to MeV photons.

[0018] Furthermore, it also includes a carbon fiber frame; the carbon fiber frame is used to support and fix the crystal and the photomultiplier tubes and silicon photomultiplier tubes at both ends, and provide support for other supporting devices. As a supporting structure, the carbon fiber frame can effectively reduce the weight of the spectrometer, while ensuring the stability and mechanical strength of the detector to meet the environmental requirements of deep space launch.

[0019] The beneficial effects of the present invention are:

[0020] 1. High-efficiency energy spectrum detection. The present invention adopts a multi-layer stacking structure of CeBr3 crystals and LYSO crystals to achieve high-efficiency energy spectrum measurement of 100keV to 20MeV high-energy photons, covering the characteristic gamma rays generated by solar flares and meeting the needs of deep space observation of the sun.

[0021] 2. High energy resolution, detection efficiency and signal-to-noise ratio. The specific stacked structure and the side-by-side arrangement of the crystals in the present invention not only ensure high energy resolution for low-energy photons, but also improve the detection efficiency for high-energy photons; the dual-end readout effectively reduces the measurement error caused by uneven transmission of photons in the crystal, and maintains good resolution in the energy range from keV to MeV; the PMT end provides high gain, and the SiPM end improves magnetic field resistance and output linearity, further enhancing the signal-to-noise ratio.

[0022] 3. Lightweight design: The present invention adopts a carbon fiber frame to control the total weight of the spectrometer within 30kg, of which the scintillation crystal part is about 15kg, which not only meets the weight restrictions of deep space exploration, but also ensures the mechanical strength and stability of the detector structure.

[0023] Fourth, strong anti-interference ability. The present invention effectively eliminates the interference of high-energy charged particles through the anti-coincidence detector, and further suppresses false signals by combining the signal fusion algorithm of double-end readout to ensure accurate identification of high-energy photon events.

[0024] 5. Adapt to deep space environment. The present invention uses a carbon fiber frame and compact layout to enable the spectrometer to have excellent stability and reliability in deep space environments, and can cope with stringent space mission requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the disassembled structure of the lightweight solar high-energy radiation spectrometer of Example 1;

[0026] Figure 2 This is a schematic diagram of the overall external structure of the lightweight solar high-energy radiation spectrometer of Example 1;

[0027] Figure 3 is a full energy peak detection efficiency curve diagram of the lightweight solar high energy radiation spectrometer of Example 2 and Example 3;

[0028] Figure 4 It is a full energy peak detection efficiency curve diagram of the lightweight solar high energy radiation spectrometer of Example 1 and Example 2. DETAILED DESCRIPTION

[0029] The specific implementation of the present invention is described below with reference to the accompanying drawings.

[0030] Example 1

[0031] like Figure 1 As shown, this embodiment provides a lightweight solar high-energy radiation spectrometer, the main body of which is a scintillator detector composed of four layers of crystal stacking: the first two layers are composed of CeBr3 crystals, and the last two layers are composed of LYSO crystals. Each layer is composed of two rectangular crystals with dimensions of 10.16cm×5.3cm×5.3cm, which are placed side by side laterally. This structural design is based on the limitations of existing crystal growth processes and aims to ensure that the crystal has sufficient effective detection area, thereby improving the detection efficiency of high-energy photons. The multi-layer superposition design can achieve more efficient measurement of photon energy through layer-by-layer absorption and mutual complementation.

[0032] The CeBr3 crystals used in the first two layers can achieve excellent energy resolution and low background noise for keV-level photons, and the LYSO crystals used in the last two layers have high density and high atomic number, which can effectively detect high-energy photons of the MeV level. Through this specific combination and arrangement, not only can high-efficiency detection be achieved in different energy ranges, but also good energy resolution can be maintained.

[0033] Specifically, CeBr3 crystals can accurately detect the energy distribution of low-energy photons due to their excellent scintillation properties and low spontaneous emission background; the density of LYSO crystals (about 7.1 g / cm 3 ) and high atomic number can effectively improve the detection efficiency of high-energy photons, and its light yield is much higher than that of traditional BGO materials, and can achieve better energy resolution under the same conditions. The combination of CeBr3 crystal and LYSO crystal can not only ensure high detection efficiency in the low-energy range, but also achieve effective detection of photons in the high-energy range, and overall meet the needs of efficient capture of photons in different energy ranges.

[0034] Each crystal is equipped with a 2-inch PMT and SiPM at both ends for signal readout. The PMT is uniformly installed on one side of the crystal, while the SiPM is attached to the other side of the crystal. This design can not only improve the energy resolution, detection efficiency and signal-to-noise ratio of the detector, but also enable the PMT and SiPM to back up each other, thereby enhancing the stability and reliability of the detector. Each signal uses independent preamplification, filtering and ADC channels for readout and digitization.

[0035] Specifically, by configuring PMT and SiPM at both ends of CeBr3 crystal and LYSO crystal respectively, dual-end readout can be achieved, which can significantly reduce the measurement error caused by uneven transmission of photons in the crystal and improve the energy measurement accuracy of each energy range from keV to MeV. At the same time, by combining the different gain characteristics of PMT and SiPM to increase the probability of photon capture and suppress noise, the detection efficiency and resolution are both improved. In addition, the respective characteristics of PMT and SiPM can also back up each other, improving the safety margin of detection and system reliability.

[0036] The support and segmentation structure is composed of a carbon fiber frame with a thickness of about 2mm. Carbon fiber materials have the characteristics of high strength and low density, which can provide the necessary mechanical support for the detector and show excellent radiation resistance and thermal stability in deep space environments. Considering that the flux of high-energy photons from the sun drops sharply with energy, a strategy of increasing the detection area rather than thickness is adopted to maximize the detection efficiency. By choosing to place them side by side horizontally, the two crystals in each layer can cover a larger effective detection area, thereby increasing the probability of capturing high-energy photons.

[0037] PSDs are set on the front and upper sides of the scintillator detector as anti-coincidence detectors to eliminate interference from high-energy charged particles from cosmic rays. The size of the front PSD is 18.5cm×11.7cm×1.5cm, and the size of the upper PSD is 18.5cm×1.5cm×31.3cm. The signals of the PSD are all read out through the PMT. Due to the large area of ​​the PSD, each PSD is equipped with two PMTs for readout, and they are installed on the same side as the PMT of the scintillator detector. This design can not only ensure the fluorescence collection efficiency of the PSD, but also play a role of mutual backup. Specifically, the PSD is sensitive to charged particles, but almost does not interact with high-energy photons. The charged particle events are distinguished and eliminated by judging the PSD signal. The PSD on the front side is responsible for the screening of charged particles on the photon incident surface, and the PSD on the upper side is used to intercept cosmic rays entering from the top.

[0038] The carbon fiber frame also includes an L-shaped carbon fiber honeycomb structure set on the right and rear sides of the scintillator detector to support and fix the PSD to ensure its structural stability. The overall layout is compact and reliable, suitable for installation in the limited space of the satellite.

[0039] The left side of the scintillator detector is equipped with the front-end electronics system, high-speed signal acquisition system and power supply.

[0040] The front-end electronics system includes signal amplification, filtering and digitization modules, which pre-amplify, filter and digitize the signals read out by each photomultiplier tube and silicon photomultiplier tube.

[0041] The PMT and SiPM at both ends of the crystal are connected to the high-speed signal acquisition system in parallel through the front-end electronics system. The PMT of the plastic scintillator is also connected to the high-speed signal acquisition system through the front-end electronics system. Each signal is processed by the high-speed signal acquisition system to ensure accurate recording and data analysis of high-energy photons.

[0042] The high-speed signal acquisition system combines the signals from the PMT and SiPM to achieve high-precision estimation of photon energy, time and position, and can comprehensively determine whether it is a valid event based on the trigger logic and anti-coincidence signal. This configuration also includes high-gain amplifiers, analog filters and high-speed analog-to-digital converters (ADCs) to ensure accurate time and energy recording of high-energy events.

[0043] This spectrometer greatly improves the detection efficiency by increasing the detection area rather than the thickness. CeBr3 crystals show high energy resolution for keV photons, while LYSO crystals have higher detection efficiency for MeV photons. The superposition of the two can achieve wide energy range measurement from 100keV to 20MeV.

[0044] Example 2

[0045] This embodiment provides a lightweight solar high-energy radiation spectrometer, which is basically the same as the embodiment 1, except that no anti-coincidence detector is provided.

[0046] Example 3

[0047] This embodiment provides a lightweight solar high-energy radiation spectrometer, which is basically the same as Embodiment 1, except that: no anti-coincidence detector is provided; the number of layers of LYSO crystal is one layer, and the size of the crystal is 15.24cm×5.3cm×5.3cm.

[0048] The full energy peak detection efficiency of the spectrometers in Example 2 and Example 3 varies with energy. Figure 2 The results show that in the range of several MeV to tens of MeV, the detection efficiency of two-layer LYSO is slightly higher than that of single-layer LYSO, while there is almost no difference in other energy bands. Based on this analysis, reducing the number of LYSO layers and expanding the detection area can increase the coverage area while maintaining the detection efficiency, which may be a more optimal choice.

[0049] In Example 2, the size of each crystal is 10.16 cm × 5.3 cm × 5.3 cm, there are 4 CeBr3 crystals and 4 LYSO crystals, the total weight is about 13.9 kg, and the detection area is about 107.7 cm 2 In Example 3, the crystal size was adjusted to 15.24 cm × 5.3 cm × 5.3 cm, with 4 CeBr3 crystals and 2 LYSO crystals, with a total weight of about 14.8 kg, which still did not exceed the weight limit, and the detection area was increased to 161.5 cm 2 Although only one layer of LYSO crystal is used in Example 3, the efficiency does not change much, but the detection area is increased by nearly 50%. Therefore, the overall layout of the crystal stacking structure can be adjusted according to the requirements of deep space observation missions. When the demand for high-energy detection is high, the number of LYSO layers can be further increased and a dual-end readout method can be used to further improve the detection efficiency and time resolution.

[0050] The full energy peak detection efficiency of the spectrometers in Example 1 and Example 2 varies with energy. Figure 3 shown.

[0051] first, Figure 3 The detection efficiency of the spectrometer for photons in different energy ranges is demonstrated. For low-energy photons (about 100keV to 1MeV), the detection efficiency is relatively high, mainly due to the high energy resolution and low background noise of CeBr3 crystals. However, as the energy increases, the detection efficiency gradually decreases, which is mainly due to the enhanced penetration of high-energy photons and the failure of some photons to be completely absorbed.

[0052] Secondly, Figure 3 The effect of the introduction of anti-coincidence detector on the overall detection efficiency is shown. Figure 3 It can be seen that the anti-coincidence detector plays an important role in eliminating false signals of high-energy charged particles. Specifically, the detection efficiency of low-energy photons is reduced due to the introduction of the anti-coincidence system. This is because some low-energy photons and the anti-coincidence detector generate unnecessary triggers, resulting in the signal being mistakenly excluded; however, for photons above 3MeV, the influence of the anti-coincidence system can be ignored, and the detection efficiency remains almost unchanged. This is because the flow rate of high-energy photons is lower and the distinction between them and charged particle signals is clearer, so the anti-coincidence detector has less impact on the high-energy segment.

[0053] In general, the addition of the anti-coincidence detector significantly improves the detection accuracy of pure high-energy photon events, especially in the presence of a large number of high-energy charged particles in the deep space environment, which can effectively reduce the proportion of false signals and enhance the reliability and accuracy of the spectrometer. At the same time, through the multi-layer superposition design, the spectrometer can maintain a good energy resolution in the detection of high-energy photons and cover a larger energy range, which makes its application in deep space observation missions have extremely high practical value.

[0054] In the present invention, unless otherwise specified, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art.

[0055] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "back", etc. cited in the invention are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0056] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A lightweight solar high-energy radiation spectrometer, characterized in that: including a scintillator detector; The scintillator detector comprises a plurality of crystal layers stacked front to back, wherein the crystal layer comprises one or more crystals arranged side by side; The crystal includes a CeBr3 crystal and a LYSO crystal, and the CeBr3 crystal is located at the front side of the LYSO crystal; Each crystal is equipped with a photomultiplier tube and a silicon photomultiplier tube at both ends, and the signals read out at both ends are fused.

2. The lightweight solar high energy radiation spectrometer according to claim 1, characterized in that: The number of layers of the CeBr3 crystal is two, and the number of layers of the LYSO crystal is at least one.

3. The lightweight solar high energy radiation spectrometer according to claim 2, characterized in that: The crystal layer includes two crystals arranged side by side, with a size of 10.16 cm×5.3 cm×5.3 cm.

4. The lightweight solar high energy radiation spectrometer according to claim 1, characterized in that: The signals read out from both ends of each crystal are pre-amplified, filtered, digitized and then fused.

5. The lightweight solar high energy radiation spectrometer according to claim 1, characterized in that: Also includes anti-coincidence detector; The anti-coincidence detector comprises a plastic scintillator arranged on the front side and the upper side of the scintillator detector, and is used for anti-coincidence detection.

6. The lightweight solar high energy radiation spectrometer according to claim 5, characterized in that: The end of the plastic scintillator is provided with a photomultiplier tube, and is installed on the same side as the photomultiplier tube of the scintillator detector.

7. The lightweight solar high energy radiation spectrometer according to claim 6, characterized in that: It also includes front-end electronics systems; The front-end electronics system includes signal amplification, filtering and digitization modules, which pre-amplify, filter and digitize the signals read out by each photomultiplier tube and silicon photomultiplier tube.

8. The lightweight solar high energy radiation spectrometer according to claim 7, characterized in that: It also includes a high-speed signal acquisition system; The photomultiplier tubes and silicon photomultiplier tubes at both ends of the crystal are connected in parallel to the high-speed signal acquisition system through the front-end electronics system; the photomultiplier tubes of the plastic scintillator are also connected to the high-speed signal acquisition system through the front-end electronics system; The high-speed signal acquisition system collects and processes the signals read out by each photomultiplier tube and silicon photomultiplier tube and provides a trigger signal.

9. The lightweight solar high energy radiation spectrometer according to claim 8, characterized in that: The high-speed signal acquisition system fuses the signals of the photomultiplier tubes and silicon photomultiplier tubes at both ends of the crystal, and determines a valid event according to the trigger logic and the anti-coincidence detection result.

10. The lightweight solar high energy radiation spectrometer according to claim 5, characterized in that: It also includes a carbon fiber frame, which is used to support and fix the crystal and the photomultiplier tubes and silicon photomultiplier tubes at both ends of the crystal and the plastic scintillator.

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