Hybrid collector-detector system for field, real-time radionuclide gas analysis

Abstract

The present disclosure presents hybrid collector-detector systems and related methods for analyzing a radionuclide gas. One such system comprises a plurality of scintillator materials comprising layers of scintillator materials; a photomultiplier; and an intake passageway that is sandwiched between the layers of scintillator materials. For such a system, the intake passageway is composed of one or more straws of radionuclide gas absorbent material having selectivity for xenon. One or more of the layers of scintillator materials emit light after being exposed to radiation that (1) is present in air that is received by the intake passageway and (2) has an energy that is within a scintillation response band of the one or more layers of scintillator materials. Further, the photomultiplier outputs an electrical signal in response to the light being emitted by the one or more layers of scintillator materials.

Description

HYBRID COLLECTOR-DETECTOR SYSTEM FOR FIELD, REAL-TIME RADIONUCLIDE GAS ANALYSISCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to co-pending U.S. provisional application entitled, “Hybrid Collector-Detector System for Field, Real-Time Radionuclide Gas Analysis,” having application number 63 / 604,711 , filed November 30, 2023, which is entirely incorporated herein by reference.BACKGROUND

[0002] There is a current need for innovative in-field methods for the detection of radionuclide noble-gases produced during nuclear fission for monitoring and verification of “zero yield” nuclear tests and related events where the concentration of radionuclide noble gases can have a wide range including trace-levels. Current detection systems are either land-based (across international borders) or involve the use of fly over air concentrators that do not have real time detection capabilities and operate at distances that reduce their ability to detect zero yield tests. Therefore, these methods lack the location versatility and or simultaneous analysis and real-time detection transmission capabilities which is particularly problematic when considering the short lifetime and highly localized concentration of some of the radionuclide species from these tests. Moreover, current air sample concentrator and collection systems are not selective to specific radionuclides and thus the collection of radon results in the radiation background preventing ultrasensitive detection of relevant species.SUMMARY

[0003] Embodiments of the present disclosure provide systems and methods for analyzing a radionuclide gas. One such system comprises a plurality of scintillator materials comprising layers of scintillator materials; a photomultiplier; and an intake passageway that is sandwiched between the layers of scintillator materials. For such a system, the intake passageway is composed of one or more straws of radionuclide gas absorbent material having selectivity for xenon. One or more of the layers of scintillator materials emit light after being exposed to radiation that (1) is present in air that is received by the intake passageway and (2) has an energy that is within a scintillation response band of the one or more layers of scintillator materials. Further, the photomultiplier outputs an electrical signal in response to the light being emitted by the one or more layers of scintillator materials.

[0004] One embodiment of such a method, among others, can be broadly summarized by the following steps: providing a hybrid collector-detector system for analyzing a radionuclide gas comprising: (1) a plurality of scintillator materials comprising layers of scintillator materials; (2) a photomultiplier; and (3) an intake passageway that is sandwiched between the layers of scintillator materials, wherein: (a) the intake passageway is composed of one or more straws of radionuclide gas absorbent material having selectivity for xenon; (b) one or more of the layers of scintillator materials emit light after being exposed to radiation that (i) is present in air that is received by the intake passageway and (ii) has an energy that is within a scintillation response band of the one or more layers of scintillator materials; and (iii) the photomultiplier outputs an electrical signal in response to the light being emitted by the one or more layers of scintillator materials. The method further comprises detecting radionuclide gases using the hybrid collector-detector system.

[0005] In one or more aspects for such systems, methods, and / or devices, the photomultiplier comprises a photomultiplier tube; the photomultiplier comprises a silicon photomultiplier; the layers of scintillator materials comprises a plastic scintillator that surrounds the straws; thallium doped cesium iodide crystals are positioned next to the plastic scintillator layer; bismuth germanate crystals are positioned next to the thallium doped cesium iodide crystal layer; the radionuclide gas absorbent material comprises zeolites; the zeolites comprise silver exchanged SSZ-112 AFT zeolite; the radionuclide gas absorbent material comprises metal-organic materials; and / or the radionuclide gas absorbent material comprises covalent organic frameworks materials.

[0006] Other systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description and be within the scope of the present disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0008] FIG. 1 shows a hybrid collector-detector system for field, real-time radionuclide gas analysis in accordance with various embodiments of the present disclosure.

[0009] FIG. 2 shows a high-level illustration of an exemplary computing device that can be used in accordance with systems and methods of the present disclosure.DETAILED DESCRIPTION

[0010] The present disclosure describes various embodiments of hybrid collectordetector system systems, apparatuses, and related methods for field, real-time radionuclide gas analysis. Accordingly, one such embodiment of the present disclosure comprises a hybrid material system for the collection, concentration, detection, and analysis of radionuclide gases from ’’zero yield” tests in real-time, as shown in FIG. 1.

[0011] The hybrid collector-detector system 100 of FIG. 1 includes a scintillator hybrid device 110 (composed of a plurality of scintillator materials) and a photomultiplier 120. The hybrid scintillator device 110 is designed to receive radiation (e.g., gamma ray) from the environment (e.g., air flow) through an intake passageway 150 and emit light that is indicative of an energy of the radiation that is in contact with the scintillator 110. In turn, the photomultiplier 120 receives the light and outputs an electrical signal that is indicative of the energy of the radiation when the radiation has an energy within a range of energies sufficient to cause scintillation of the scintillator 110. In various embodiments, the system can be manufactured as a single device having a protective packaging 130. The resulting ensemble can be interfaced with detector electronics 140.

[0012] By way of example, and not limitation, the photomultiplier 120 can be a photomultiplier tube (PMT) or a silicon photomultiplier (SiPM). The detector electronics 140 can be any of various types of hardware logic component, such as a microcontroller, field-programmable gate array (FGPA) or application-specificintegrated circuit (ASIC). The detector electronics 140 can be configured to sample the electrical signal output by the photomultiplier 120 and to generate spectral data based upon the electrical signal, wherein the spectral data is indicative of an energy of the radiation (e.g., the gamma ray) received by the scintillator hybrid device 110.

[0013] In accordance with various embodiments, the scintillator hybrid device is comprised of one or more radionuclide gas absorbent materials 110 (e.g., zeolites, metal-organic (MOF), covalent organic frameworks (COF)) with a selectively for xenon that are manufactured into thin walled-cylinders (“straws”) 10 defining the intake passageway 150. The straws 10 are sandwiched between xenon detector layers 20, 30, 40 and used to measure real-time xenon concentrations and possibly detect low level nuclear testing.

[0014] In various embodiments, commercially available scintillators (TRL 10) can be used as xenon detector layers within the scintillator hybrid device 110. In the nonlimiting example of FIG. 1 , a plastic scintillator (e.g. BC-400) sheath is used in layer 20 and surrounds the straws 10 and couples the plastic scintillator 20 with an intermediate layer 30 of thallium doped cesium iodide Csl(TI) crystals for gamma detection and an outer layer 40 of BGO crystals for Compton suppression. In various embodiments, the resulting ensemble can be interfaced with commercially available photomultiplier(s) 120 (e.g., PMT and SiPM, both TRL 10) and detector electronics 140.

[0015] Within the collection (scrubber) materials, zeolites, in particular silver- exchanged ones such as Ag-chabazite, are well-known for their excellent radionuclide gas adsorption, despite the fundamental mechanisms responsible for adsorption not being well understood. Through first principles simulations (Density Functional Theory (DFT)), we have recently identified key crystallochemical characteristics that can beused as rules or guidelines for the design and identification of advanced collection systems with xenon selectivity. See J.C. Nino, "Designed Selectivity in Zeolites for Radionuclide Gas Adsorption and Detection", DTRA Consortium - Interaction of Ionizing Radiation with Matter RA-3 Project Progress Update (May 2023).

[0016] In addition, Becker et al., have demonstrated a phoswich (phosphorous sandwich) detector based on three scintillator layers, including a plastic scintillator (beta detection), Csl(TI) crystal (x- and gamma rays), and a bismuth germanate (Bi4Ge30i2, BGO) crystal (Compton suppression), that is capable of beta-gamma coincidence measurements for the detection of radioxenon. See A.T. Farsoni, B. Alemayehu, A. Alhawsawi, and E.M. Becker, "A Phoswich Detector With Compton Suppression Capability for Radioxenon Measurements,” IEEE T Nucl Sci 60 [1] 456- 464 (2013).

[0017] Thus, inspired by these two advancements, the present disclosure presents hybrid-material techniques for the real-time collection and detection of radionuclide gases. In the process of developing such techniques, key crystallochemical characteristics were first identified, through principles simulations (DFT), that can be used as rules or guidelines for the design and identification of advanced collection systems with xenon selectivity. Following the DFT predictions, in various embodiments, silver exchanged SSZ-112 AFT zeolite can be synthesized and tubular structures can be manufactured to form “straws” for single and array collectors. As such, the straws can form the skeleton of an exemplary nearly 4n phoswich detector where detection is achieved through Compton and background suppressed betagamma coincidence measurements via crystalline and polymeric scintillators and Si- photomultipliers, in accordance with various embodiments of the present disclosure. It is important to note that while SSZ-112 is a novel relatively unexplored compound(TRL 1 ), is expected to offer a similar Xe binding mechanism along with the comparative advantage over Ag-chabazite of having additional crystallographic and structural sites for Ag and Xe.

[0018] Thus, advanced zeolites with radionuclide gas selectivity can be manufactured into “straw-like” concentrators to form the skeleton of an innovative nearly 4TT phoswich detector where detection is achieved through Compton and background suppressed beta-gamma coincidence measurements via crystalline and polymeric scintillators and Si-photomultipliers.

[0019] For an exemplary embodiment, commercially available scintillators (TRL 10) can be used, where we can use a plastic scintillator (e.g. BC-400) sheath surrounding the zeolite straws and couple the plastic scintillator with an intermediate layer of Csl(TI) crystals for gamma detection and an outer layer BGO crystals for Compton suppression. The resulting ensemble can be interfaced with commercially available photomultipliers (e.g., PMT and SiPM, both TRL 10) and detector electronics. In various embodiments, an optimized multiplexed array can be manufactured in addition to the single straw design. Such real-time hybrid-material systems and methods for the real-time collection and detection of radionuclide gases are designed to detect concentrations of Xe in the presence of Radon (Rn) and air (O2, N2, H2O).

[0020] Benefits of the disclosed systems and methods include low power, realtime, with high selectivity and increased sensitivity (real-time Rn daughter rejection) compared with current concentrator lab-based testing methods. Advancements achieved by the disclosed systems and methods include synthesis of advanced zeolites with increased selectivity for xenon, manufacture of zeolite collector structures with optimal collection geometries and adequate mechanical properties (e.g., DFT- optimized zeolite structure), coupling of zeolite structures with wrap-around scintillatorand photomultiplier system, GEANT-optimized collector-detector geometry, Xenon detection with prototype phoswich detectors, novel multiplexed detector prototype demonstration using arrays of zeolite structures and detectors, and minimum detectability determination.

[0021] Referring now to FIG. 2, a high-level illustration of an exemplary computing device 200 that can be used in accordance with systems and methodologies disclosed herein is illustrated. For instance, the computing device 200 may be used in the detector electronics 150. The computing device 200 includes at least one processor 210 that executes instructions that are stored in a memory 220. The instructions may be, for instance, instructions for implementing functionality described as being carried out by one or more components discussed above or instructions for implementing one or more of the methods described above. The processor 210 may access the memory 220 by way of a system bus 230. In addition to storing executable instructions, the memory 220 may also store spectral data, detection data, control parameters for a radiation spectrometer system, etc.

[0022] The computing device 200 additionally includes a data store 240 that is accessible by the processor 210 by way of the system bus 230. The data store 240 may include executable instructions, control parameters, spectral data, etc. The computing device 200 also includes an input interface 250 that allows external devices to communicate with the computing device 200. For instance, the input interface 250 may be used to receive instructions from an external computer device, from a user, etc. The computing device 200 also includes an output interface 260 that interfaces the computing device 200 with one or more external devices. For example, the computing device 200 may display text, images, etc., by way of the output interface 260.

[0023] It is contemplated that the external devices that communicate with the computing device 200 via the input interface 250 and the output interface 260 can be included in an environment that provides substantially any type of user interface with which a user can interact. Examples of user interface types include graphical user interfaces, speech interfaces, visual / gesture interfaces, and so forth. Additionally, while illustrated as a single system, it is to be understood that the computing device 200 may be a distributed system. Thus, for instance, several devices may be in communication by way of a network connection and may collectively perform tasks described as being performed by the computing device 200.

[0024] Various functions described herein can be implemented in hardware, software, or any combination thereof. If implemented in software, the functions can be stored on or transmitted over as one or more instructions or code on a computer- readable medium. Computer-readable media includes computer-readable storage media. A computer-readable storage media can be any available storage media that can be accessed by a computer. By way of example, and not limitation, such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc (BD), where disks usually reproduce data magnetically and discs usually reproduce data optically with lasers. Further, a propagated signal is not included within the scope of computer-readable storage media. Computer-readable media also includes communication media including any medium that facilitates transfer of a computer program from one place to another. Aconnection, for instance, can be a communication medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio and microwave are included in the definition of communication medium. Combinations of the above should also be included within the scope of computer-readable media.

[0025] Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include FPGAs, ASICs, Application-specific Standard Products (ASSPs), System-on- a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc.

[0026] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the principles of the present disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure.

Claims

CLAIMSWe claim:

1. A hybrid collector-detector system for analyzing a radionuclide gas comprising: a plurality of scintillator materials comprising layers of scintillator materials; a photomultiplier; and an intake passageway that is sandwiched between the layers of scintillator materials, wherein: the intake passageway is composed of one or more straws of radionuclide gas absorbent material having selectivity for xenon; one or more of the layers of scintillator materials emit light after being exposed to radiation that (1 ) is present in air that is received by the intake passageway and (2) has an energy that is within a scintillation response band of the one or more layers of scintillator materials; and the photomultiplier outputs an electrical signal in response to the light being emitted by the one or more layers of scintillator materials.

2. The system of claim 1 , wherein the photomultiplier comprises a photomultiplier tube.

3. The system of claim 1 , wherein the photomultiplier comprises a silicon photomultiplier.

4. The system of claim 1 , wherein the layers of scintillator materials comprises a plastic scintillator that surrounds the straws.

5. The system of claim 4, wherein thallium doped cesium iodide crystals are positioned next to the plastic scintillator layer.

6. The system of claim 5, wherein bismuth germanate crystals are positioned next to the thallium doped cesium iodide crystal layer.

7. The system of claim 1 , wherein the radionuclide gas absorbent material comprises zeolites.

8. The system of claim 7, wherein the zeolites comprise silver exchanged SSZ-112 AFT zeolite.

9. The system of claim 1 , wherein the radionuclide gas absorbent material comprises metal-organic materials.

10. The system of claim 1 , wherein the radionuclide gas absorbent material comprises covalent organic frameworks materials.

11. A method for analyzing a radionuclide gas comprising: providing a hybrid collector-detector system for analyzing a radionuclide gas comprising:a plurality of scintillator materials comprising layers of scintillator materials; a photomultiplier; and an intake passageway that is sandwiched between the layers of scintillator materials, wherein: the intake passageway is composed of one or more straws of radionuclide gas absorbent material having selectivity for xenon; one or more of the layers of scintillator materials emit light after being exposed to radiation that (1 ) is present in air that is received by the intake passageway and (2) has an energy that is within a scintillation response band of the one or more layers of scintillator materials; and the photomultiplier outputs an electrical signal in response to the light being emitted by the one or more layers of scintillator materials; and detecting radionuclide gases using the hybrid collector-detector system.

12. The method of claim 11 , wherein the detecting of radionuclide gases using the hybrid collector-detector system comprises measuring real-time xenon concentrations in the air.

13. The method of claim 11 , wherein the radionuclide gas absorbent material comprises zeolites.

14. The method of claim 13, wherein the zeolites comprise silver exchangedSSZ-112 AFT zeolite.

15. The method of claim 11 , wherein the radionuclide gas absorbent material comprises metal-organic materials or covalent organic frameworks materials.

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