REAL TIME ENVIRONMENTAL RADIATION MONITORING

Abstract

A wearable dosimeter providing real-time radiation measurements based on sensitive, high gain scintillator crystals and a multipixel photon counter.

Claims

1. A wearable real-time radiation dosimeter, comprising: a) a housing having an exterior surface surrounding an interior space; b) said exterior surface having at least: i) a display for displaying a measured radiation dosage; ii) an on/off switch for activating said display; iii) means for mounting said housing to an item of clothing; c) said interior space containing therein a plurality of layers stacked in the following order: i) a crystal scintillator optically coupled to a silicon photomultiplier (SiPM) for detecting photons, said crystal scintillator SiPM having the following characteristics: (1) a lower limit on noise-equivalent dose (NED) of 0.01 mrem-0.1 mrem; (2) detection capability of at least 5 keV-5 MeV photon energies; (3) a continuous dose measurement range of at least 0.01 mrem/s-1 rem/s; (4) an operating temperature of at least 2510 C.; and (5) an accuracy of at least5%; ii) said silicon photomultiplier (SiPM) being electrically coupled to a printed circuit board comprising: (1) a transimpedence amplifier for amplifying an analog voltage from said SiPM operably coupled to: (2) an analog to digital converter for converting said analog voltage to a digital voltage operably coupled to: (3) a microprocesser for converting said digital voltage to a dosage operably coupled to: (4) a memory for storing said dosage operably coupled to: (5) a wireless transmitter for transmitting said dosage to a separate device; and (6) a power source configured to power said dosimeter.

2. The dosimeter of claim 1, wherein said crystal scintillator is coated on all sides that do not optically couple to said SiPM with an inward facing reflective coating.

3. The dosimeter of claim 2, wherein said crystal scintillator is in the shape of a cylinder, having a flat side optically coupled to said SiPM.

4. The dosimeter of claim 2, wherein said crystal scintillator is in the shape of a hemisphere, having a flat side optically coupled to said SiPM.

5. The dosimeter of claim 1, wherein said crystal scintillator is a LaBr(Ce) crystal and said LaBr(Ce) crystal is hermetically sealed.

6. The dosimeter of claim 1, wherein said crystal scintillator is a Lutetium Fine Silicate (LFS) crystal scintillator.

7. The dosimeter of claim 1, wherein SiPM is a multipixel photon counter (MPPC).

8. The dosimeter of claim 1, wherein said exterior surface has an access hatch for accessing a power source or data or both.

9. The dosimeter of claim 1, wherein said power source is a battery and said exterior surface has an access hatch for accessing said battery or data or both.

10. The dosimeter of claim 1, wherein said power source is a rechargeable battery and said exterior surface has an access hatch for accessing said rechargeable battery.

11. The dosimeter of claim 1, wherein said exterior surface has an inductive charging plate and said power source is an inductively rechargeable battery.

12. The dosimeter of claim 1, wherein said exterior surface has a data port for loading one or more conversion factor(s) for converting voltage to dosage.

13. The dosimeter of claim 1, wherein said exterior surface has a data port for loading one or more conversion factor(s) for converting voltage to dosage and for powering a rechargeable power source.

14. The dosimeter of claim 1, wherein said exterior surface has an on/off switch for initiating data transmission.

15. The dosimeter of claim 1, wherein said dosimeter has means for automatically initiating data transmission in proximity to a receiver.

16. The dosimeter of claim 1, wherein a transparent epoxy layer adheres said scintillator crystal scintillator to said SiPM.

17. The dosimeter of claim 1, wherein said display is a LCD or LED display.

18. The dosimeter of claim 1, wherein components c)-i) to c)-ii) are hermetically sealed inside said housing so as to exclude moisture.

19. The dosimeter of claim 1, further comprising a unique serial number that functions as a user ID.

20. The dosimeter of claim 19, wherein said user ID comprises an iBeacon or Bluetooth communication protocol.

21. The dosimeter of claim 1, wherein said wireless transmitter is configured to receive calibration data, or wherein said device housing has a dataport for receiving calibration data.

22. The dosimeter of claim 21, wherein said scintillation crystal has a footprint of 5 mm5 mm or less.

23. A wearable real-time radiation dosimeter, comprising: a) a light tight housing having an exterior surface surrounding an interior space; b) said exterior surface having: i) a LED or LCD display; ii) an on/off switch for activating said display; iii) an optional on/off switch for initiating data transmission; iv) means for mounting said housing to an item of clothing; and v) a data port for loading a conversion factor for converting voltage to dosage; c) said interior space containing a plurality of layers stacked in the following order: i) a mirrored surface coating; ii) an LFS crystal scintillator; iii) a transparent epoxy layer; iv) a multipixel photon counter (MPPS) for providing an analog voltage in response to light emitted by said LFS crystal scintillator; v) a printed circuit board electrically coupled to said MPPC and comprising: (1) a temperature compensation circuit and a signal amplifier operably coupled to: (2) an analog to digital converter for converting said analog voltage to a digital voltage operably coupled to: (3) a microprocesser for converting said digital voltage to a daily dosage using a conversion factor operably coupled to: (4) a memory for storing said daily dosage and a cumulative dosage operably coupled to: (5) a wireless transmitter for transmitting said daily dosage and said cumulative dosage to a separate device.

24. A real-time radiation dosimeter, comprising a housing having a plurality of components therein that are operably connected together to measure radiation dosage, said components comprising: a) a detector sandwich protected from stray light, said detector sandwich comprising a plurality of layers stacked in the following order: i) a mirrored surface coating; ii) a crystal scintillator having: (1) a lower limit on noise-equivalent dose (NED) of 0.01 mrem-0.1 mrem; (2) a detection capability of at least 5 keV-5 MeV; (3) a continuous dose measurement range of 0.01 mrem/s-1 rem/s; (4) an operating temperature of at least 2510 C.; and (5) an accuracy of 5%; iii) a multipixel photon counter (MPPS) for providing an analog voltage in response to light emitted by said LFS crystal scintillator; b) means for on-board temperature compensation and dark matter compensation; c) means for on-board calculation of daily dosage and cumulative dosage; d) means for on-board displaying of said daily dosage and said cumulative dosage; e) means for powering said dosimeter; and f) means for wirelessly transmitting said daily dosage and said cumulative dosage to a remote system.

25. The dosimeter of claim 24, wherein said crystal scintillator is an LFS crystal scintillator.

26. A method of monitoring radiation dosage, said method comprising: a) wearing the dosimeter of claim 1 during radiation procedures; b) calculating a real-time dosage using said dosimeter; c) storing said dosage in said memory; d) repeating steps a to c on an ongoing basis; e) wirelessly transmitting dosage information from said memory to a separate processor at intervals; and f) storing said dosage information from step e in said separate processor.

27. The method of claim 26, further comprising reporting said dosage information to said display or to a third party or to a third-party processor.

28. The method of claim 26, further comprising reporting said dosage information to a warning system when said dosage approaches a predetermined danger limit.

29. A method of monitoring radiation dosage, said method comprising: a) wearing the dosimeter of claim 24 during a daily radiation procedure; b) calculating a daily dosage using said dosimeter; c) storing said daily dosage and a cumulative dosage in said memory; d) repeating steps a) to c) on additional days; e) wirelessly transmitting said daily dosage and said cumulative dosage from said memory to a separate processor at intervals; and f) storing said daily dosage and said cumulative dosage from step e) in said separate processor.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0054] FIG. 1 shows a perspective view of one embodiment of the device.

[0055] FIG. 2A shows a cross section of the detector sandwich of FIG. 1.

[0056] FIG. 2B shows a device like that of FIG. 2A, but with a hemispherical crystal.

[0057] FIG. 2C shows a device like that of FIG. 2A, but with a cylindrical crystal.

[0058] FIG. 3 is a side view of the device of FIG. 1.

[0059] FIG. 4 is a perspective view of another embodiment of the complete device.

[0060] FIG. 5 is a block diagram of an MPPC module.

[0061] FIG. 6A-6E is the printed circuit board and layout of the MPPC module.

DETAILED DESCRIPTION OF THE INVENTION

[0062] The following descriptions and figures are exemplary only and should not be used to unduly limit the scope of the invention.

[0063] According to a study conducted by the Department of Radiological Technology in the School of Health Sciences at Tohoku University, the annual mean dose equivalent exposure during electrophysiology and interventional radiology procedures was 19.8412.45 and 4.730.72 mSv/y to the neck for physicians and nurses respectively. Each of the 18 physicians in the study performed and average of 293.3144.8 coronary angiography and 73.738.9 percutaneous coronary intervention (PCI) procedures annually. On average, each of the 7 nurses was involved in 754.3352.3 coronary angiography and 189.4PCI procedures annually. From this data, we estimate that the average exposure (per combined coronary angiograph and PCI procedure) to physicians and nurses is 0.054 mSv [0.0054 cGy] and 0.005 mSv [0.0005 cGy] respectively.

[0064] In order to effectively monitor these dose levels, the detector must have high sensitivity. Ideally, the minimum detectable dose of the measurement system would be 10-100 times lower than the dose received during treatments to accurately monitor and store the accumulated dose during the procedures. This imposes a lower limit on the noise-equivalent dose (NED) of the dosimetry badge of 0.00001-0.0001 cGy [0.01 mrem-0.1 mrem]. Most commercially available badge dosimeters lack this sensitivity. For example, Landauer's Luxel OSL dosimetry badge has a lower limit of 1 mrem2 mrem.

[0065] Our wearable real-time occupational radiation monitoring detection system thus consists of a scintillation crystal coupled to a suitable photometer and meets the following technical specifications: [0066] Detection capability of at least 5 keV-5 MeV photons [0067] Continuous Dose Measurement Range of at least 0.01 mrem/s-1 rem/s [0068] Operating Temperature of at least 2510 C (though MPCCs function at 40 to 85 C.), [0069] Accuracy of at least5%.

[0070] TABLES 1-5 show scintillation crystal properties.

[0071] FIG. 1 is a perspective view of one embodiment of the device. In the perspective view of the complete device 100, the housing exterior surface 105 shows a display 101 and on/off switches 103. Also seen is access hatch 107 for reaching the power source, typically a battery. The detector sandwich can also be seen, as one wall is omitted for visibility. The access hatch could be a USB or other port, and thus serve for both recharging an interior battery as well as for data communications. Alternatively, it can be merely a door to reach the battery.

[0072] The detector sandwich is seen in greater detail in the cross-sectional view of FIG. 2A-2C, where we see the reflective coating 117a covering the scintillator crystal 115a on all surfaces except the one that is optically coupled to the SiPM 113 below. This is then mounted on a printed circuit board 111, which hosts the electronics needed to convert the current generated by photons impacting the SiPM to voltage and then to dosage information. A power source 109 powers the various electronics, including SiPM, current amplifier if used, digital to analog converter, microprocessor and memory, as well as data transmission components. FIG. 2B shows a hemispherical crystal scintillator 115b and coating 117b. FIG. 2C shows a cylinder 115c and coating 117c.

[0073] A means for clipping the device to a shirt or pocket can be seen in the side view 300 of FIG. 3, where the housing 119 is shown with clip 121, and access hatch 107. Of course, a pin, alligator clip, spring clip, magnet, and any other attachment means could be used.

[0074] FIG. 4 is a perspective view of another embodiment of a complete device 400. The housing 401 exterior surface shows a display 403, display switch 405 and data transmission switch 407. Also seen is data port 409, used for calibration purposes, and inductive charging plate 411 in dotted outline on the base. In dotted line inside the housing, the detector sandwich 501 can be seen. The attaching means are not seen behind the device in this view.

[0075] In our prototypes, we used a MPPC module from Hamatsu (C13367-3050EA), with a separate 665 mm LFS crystal, also from Hamatsu. During prototype development, the crystal was optically coupled with optical glue or KY jelly, but for manufacturing, the crystal can be purchased already coupled to the MPPC.

[0076] The MPPC module comes preassembled with an MPPC (3600 pixels, 33 mm) with flexible cable, a signal amplifier circuit, a high voltage power supply circuit, and a temperature compensation circuit. The photosensitive area is 33 mm and the output is analog. The module will operate if connected to an external power supply (+/5 V). The MMCX coaxial cable for analog output is added at the customer site. A block diagram of the module is shown in FIG. 5, and the PCB with MPPC mounted thereon (large square) is shown in FIG. 6. The performance characteristics of this module are shown in TABLE 5.

[0077] We will test and validate thermal and vibrational performance of the modules by subjecting them to various external temperature and vibration changes consistent with normal wear of the device. The modules will be packaged and hermetically sealed and irradiated using X-rays from 5-5000 keV to assess linearity over the diagnostic imaging range. We will also determine the minimum detectable dose and dose accuracy over this energy range to determine necessary changes or refinements to the modules to meet the performance specifications.

[0078] We expect to measure a linear response across the entire energy range tested, consistent with the Brilliance 380 and/or LFS technical specifications. We also expect to be able to accurately characterize the minimum detectible dose and accuracy of the dosimetry badge across the entire energy range. We expect that refinements to the electronic design and SiPM modules may be necessary based on preliminary findings after these initial studies. Given our past experience in designing PSD systems, we do not expect any major obstacles in procurement, design, or engineering of the detector modules.

[0079] We will also develop a suitable wireless transmission system capable of displaying and transmitting real-time dose data and accumulated dose data stored on the modules to a mobile application or display station.

[0080] We will develop, e.g., a Bluetooth based wireless transmission and receiver system. The system will display dose measurements on the badge and deliver encrypted data over Bluetooth channel to a display station and/or mobile application. The dose data will be accessible to the user and medical staff, but remain HIPPA compliant and protected using biometric and/or login credentials.

[0081] A partner will design, develop, and implement the necessary software/hardware and transmission protocols to incorporate the display, transmission, storage, and retrieval of the dose data from the dosimetry badge module to the mobile display station. We will then test the wireless transmission and retrieval of data during and after irradiation of the dosimetry modules.

[0082] Beacon is a protocol developed by Apple and introduced in 2013. Various vendors have since made iBeacon-compatible hardware transmitterstypically called beaconsa class of Bluetooth low energy (BLE) devices that broadcast their identifier to nearby portable electronic devices. The technology enables smartphones, tablets and other devices to perform actions when in close proximity to an iBeacon.

[0083] iBeacon is based on Bluetooth low energy proximity sensing by transmitting a universally unique identifier picked up by a compatible app or operating system. The identifier and several bytes sent with it can be used to determine the device's physical location, track customers, or trigger a location-based action on the device such as a check-in on social media or a push notification. In this instance, the technology will be used to identify a user, initiate a wireless connection, and automatically upload identity and dose information to a receiver or base unit.

[0084] Other beacon technologies exist, such as Google's Eddyston beacon, and the like, and any new wireless communication protocols can be used.

[0085] Various protocols are available for uploading data on proximity. For example, U.S. Pat. No. 9,560,143 (incorporated by reference in its entirety for all purposes) describes a system and method for automatic session data transfer between computing devices based on zone transition detections. A wearable computing device has 1) a data processor; 2) a memory coupled with the data processor for persistent user data storage; 3) a wireless transceiver in data communication with the data processor; 4) a unique user identifier storable in the memory; and 5) logic, at least a portion of which is partially implemented in hardware, configured to wirelessly receive an upload of user session data from a first computing device via the wireless transceiver, to store the user session data in the memory, to authenticate a second computing device using the unique user identifier, and to wirelessly download the user session data from the memory to the authenticated second computing device via the wireless transceiver, the user session data including data for recreating a computing session from the first computing device on the second computing device.

[0086] Similar technologies are described e.g., in US20050221829, US20060026288 and US20140073300, each incorporated by reference in its entirety for all purposes. US20130102250, for example, describes a system for transferring active communication sessions between apparatuses. In one implementation, a first apparatus may receive information including at least identity information corresponding to a second apparatus via close-proximity wireless communication. The receipt of the identity information then triggers the first apparatus to determine whether it is already in a communication session. If it is determined that the first apparatus is in a communication session, it may be further determined, based on the identity information, whether automatic transfer of the communication session is permitted. If the first apparatus determines that the automatic transfer is permitted, the first apparatus may then initiate a transfer of the communication session to the second apparatus.

[0087] We expect to successfully design and implement a wireless transmission system capable of displaying, sending, retrieving, and storing dose information unique to each badge and user. Bluetooth technology is a standard used throughout the medical device and consumer markets and parts are readily available. Our partner also has specific expertise in Bluetooth technology, security, usability, and engineering of medical devices as well as ISO and IEC certifications in Risk (ISO 14971), Software (IEC 62304), Quality (ISO 13485), and Electrical (IEC 60601).

[0088] The wireless communication interface may include a short range (e.g., WiFi, Bluetooth, and other wireless local area network (WLAN) protocols) and/or a long range (e.g., wireless wide area network (WWAN), mobile cellular, etc.) wireless communication interface(s). For example, the interface may allow for communications to be transmitted and received to/from the wearable radiation detector and other electronic devices. The other electronic devices may be local or remotely located devices such as sensors, computers, servers, monitors, controllers, etc. The other electronic devices may set the wearable device's radiation detector thresholds or other parameters, and may have access to the radiation levels detected by the radiation detectors. For example, the wireless communication interface may transmit the radiation information (e.g., radiation type, radiation levels, warnings, etc.) to a remote server where such data is monitored by other personnel and/or recorded. The system could also push communications to the user, e.g., a user's smart phone may receive monthly dose information.

[0089] The following citations are incorporated by reference herein in their entireties for all purposes:

[0090] U.S. Pat. No. 7,126,121 Real-time video radiation exposure monitoring system

[0091] US20150237419 Radiation exposure monitoring device and system

[0092] van Loef et al., Scintillation properties of LaBr.sub.3:Ce.sup.3+ crystals: fast, efficient and high-energy-resolution scintillators, Nucl. Instr. Meth. Physics Res. A 486:254-258 (2002).

[0093] U.S. Pat. Nos. 7,067,815; 7,067,816; 7,250,609; 7,233,006.

[0094] T. Miura, T., et al., Development of a scintillation detector using a MPPC as an alternative to an APD, THE 9th INTERNATIONAL CONFERENCE ON POSITION SENSITIVE DETECTORS, 12-16 SEPTEMBER 2011, available online at iopscience.iop. org/article/10.1088/1748-0221/7/02/CO2036/pdf.

[0095] Meskal, J. Z., Detector and detector systems for particle and nuclear physics (2015), online at oeaw. ac. at/fileadmin/sub sites/etc/Institute/SMI/PDF/Detectors_WS2014-15_A2.pdf

[0096] Boltruczyka, G., et al., Development of MPPC-based detectors for high count rate DT campaigns at JET, Proceedings of 29th Symposium on Fusion Technology (SOFT 2016), available online at euro-fusionscipub.org/wp-content/uploads/WPJET4CP16_15430_submitted. pdf

[0097] Ginzburg, D., et al., Personal radiation detector at a high technology readiness level that satisfies DARPA's SN-13-47 and SIGMA program requirements, Nuclear Instruments and Methods in Physics Research A784: 438-447 (2015), available online at infona.pl/resource/bwmetal.element.elsevier-6ee3ce2c-9de9-3b0b-8e65-744e83c2c565.

[0098] US20050221829 System and method for proximity motion detection in a wireless network

[0099] US20060026288 Method and apparatus for integrating wearable devices within a SIP infrastructure

[0100] US20130102250 Close-proximity wireless communication transfer

[0101] US20140073300 Managing Telecommunication Services using Proximity-based Technologies

TABLE-US-00001 TABLE 1 Light yield after Light yield ER for exposure ER after DT Time of exposure Compound (photon/MeV) Cs137 (percent) exposure (ns) Hygroscopicity Srf changes 1 2 3 4 5 6 7 8 La.sub.(1mn)Hf.sub.nCe.sub.mBr.sub.(3+n) La.sub.0.95Ce.sub.0.05Br.sub.3 63000 2.8 40 6.3 18 hygrosc. T = 2 h. Srf clouded, Srf structure changed La.sub.0.948Hf.sub.0.002Ce.sub.0.05Br.sub.3.002 62000 2.8 96 2.9 18 nonhygr. T = 4 h. Srf not changed La.sub.0.986Hf.sub.0.004Ce.sub.0.01Br.sub.3.004 60000 2.9 96 3.0 20 nonhygr. T = 4 h. Srf not changed La.sub.0.935Hf.sub.0.015Ce.sub.0.05Br.sub.3.015 60000 3.0 97 3.1 21 nonhygr. T = 4 h. Srf not changed Crystal colored La.sub.(1mn)Hf.sub.nCe.sub.mCl.sub.(3+n) La.sub.0.90Ce.sub.0.10Cl.sub.3 45000 3.8 50 7 20 hygrosc. T = 2 h. Srf clouded, Srf structure changed La.sub.0.919Hf.sub.0.001Ce.sub.0.08Cl.sub.3.001 44000 4.2 90 4.6 21 slightly T = 4 h. Srf clouded hygrosc. slightly, Srf structure not changed La.sub.0.916Hf.sub.0.004Ce.sub.0.08Cl.sub.3.004 43000 4.3 94 4.4 22 nonhygr. T = 4 h. Srf not changed La.sub.0.905Hf.sub.0.015Ce.sub.0.08Cl.sub.3.015 41000 4.4 96 4.5 22 nonhygr. T = 4 h. Srf not changed, crystal colored La.sub.(1mn)Hf.sub.nCe.sub.mI.sub.(3+n) La.sub.0.95Ce.sub.0.05I.sub.3 31000 5.3 48 7.2 24 hygrosc. T = 2 h. AA Srf clouded, Srf structure changed La.sub.0.945Hf.sub.0.005Ce.sub.0.05I.sub.3.005 30000 5.4 95 5.5 24 nonhygr. T = 4 h. Srf not changed Gd.sub.(1mn)Hf.sub.nCe.sub.mBr.sub.(3+n) Gd.sub.0.979Hf.sub.0.001Ce.sub.0.02Br.sub.3.001 35000 9.4 87 10 20 slightly T = 4 h. Srf clouded hygrosc. slightly, Srf structure not changed Gd.sub.0.948Hf.sub.0.002Ce.sub.0.05Br.sub.3.002 38000 9.1 94 9.3 19 nonhygr. T = 4 h. Srf not changed Gd.sub.(1mn)Hf.sub.nCe.sub.mCl.sub.(3+n) Gd.sub.0.948Hf.sub.0.002Ce.sub.0.05Cl.sub.3.002 29000 12 95 12.1 22 nonhygr. T = 4 h. Srf not changed Gd.sub.0.988Hf.sub.0.002Ce.sub.0.01Cl.sub.3.002 24000 12.8 96 13 20 nonhygr. T = 4 h. Srf not changed Lu.sub.(1mn)Hf.sub.nCe.sub.mBr.sub.(3+n) Lu.sub.0.988Hf.sub.0.002Ce.sub.0.01Br.sub.3.002 20000 7.5 93 7.7 32 nonhygr. T = 4 h. Srf not changed Lu.sub.0.948Hf.sub.0.002Ce.sub.0.05Br.sub.3.002 27000 6.4 94 6.6 30 nonhygr. T = 4 h. Srf not changed Lu.sub.(1mn)Hf.sub.nCe.sub.mI.sub.(3+n) Lu.sub.0.988Hf.sub.0.002Ce.sub.0.01I.sub.3.002 50000 4.2 56 7.3 27 hygrosc. T = 3 h. Srf clouded, AA Srf structure changed Lu.sub.0.986Hf.sub.0.004Ce.sub.0.01I.sub.3.004 45000 4.4 96 4.5 30 nonhygr. T = 4 h. Srf not changed Y.sub.(1mn)Hf.sub.nCe.sub.mI.sub.(3+n) Y.sub.0.948Hf.sub.0.002Ce.sub.0.05I.sub.3.002 42000 4.5 95 4.6 35 nonhygr. T = 4 h. Srf not changed Y.sub.0.946Hf.sub.0.004Ce.sub.0.05I.sub.3.004 43000 4.6 96 4.7 36 nonhygr. T = 4 h. Srf not changed

TABLE-US-00002 TABLE 2 Ln.sub.(1m)Ce.sub.mA.sub.3: nHf.sup.4+ Light n yield after Matrix (mol Light yield ER for exposure ER after DT Time of exposure material %) (photon/MeV) Cs137 (percent) exposure (ns) Hygroscopicity Srf changes 1 2 3 4 5 6 7 8 9 La.sub.0.95Ce.sub.0.05Br.sub.3 0 63000 2.8 40 6.3 18 hygrosc. T = 2 h. Srf clouded, Srf structure changed La.sub.0.95Ce.sub.0.05Br.sub.3 0.2 62000 2.8 96 2.9 18 nonhygr. T = 4 h. Srf not changed La.sub.0.99Ce.sub.0.01Br.sub.3 0.4 60000 2.9 96 3.0 20 nonhygr. T = 4 h. Srf not changed La.sub.0.95Ce.sub.0.05Br.sub.3 1.5 60000 3.0 97 3.1 21 nonhygr. T = 4 h. Srf not changed, crystal colored La.sub.0.90Ce.sub.0.10Cl.sub.3 0 45000 3.8 50 7 20 hygrosc. T = 2 h. Srf clouded, Srf structure changed La.sub.0.92Ce.sub.0.08Cl.sub.3 0.1 44000 4.2 90 4.6 21 slightly hygrosc. T = 4 h. Srf slightly clouded, Srf structure not changed La.sub.0.92Ce.sub.0.08Cl.sub.3 0.4 43000 4.3 94 4.4 22 nonhygr. T = 4 h. Srf not changed La.sub.0.92Ce.sub.0.08Cl.sub.3 1.5 41000 4.4 96 4.5 22 nonhygr. T = 4 h. Srf not changed, crystal colored La.sub.0.95Ce.sub.0.05I.sub.3 0 31000 5.3 48 7.2 24 hygrosc. T = 2 h. Srf clouded, AA Srf structure changed La.sub.0.95Ce.sub.0.05I.sub.3 0.5 30000 5.4 95 5.5 24 nonhygr. T = 4 h. Srf not changed Gd.sub.0.98Ce.sub.0.02Br.sub.3 0.1 35000 9.4 87 10 20 slightly hygrosc. T = 4 h. Srf slightly clouded, Srf structure not changed Gd.sub.0.95Ce.sub.0.05Br.sub.3 0.2 38000 9.1 94 9.3 19 nonhygr. T = 4 h. Srf not changed Gd.sub.0.95Ce.sub.0.05Cl.sub.3 0.2 29000 12 95 12.1 22 nonhygr. T = 4 h. Srf not changed Gd.sub.0.99Ce.sub.0.01Cl.sub.3 0.2 24000 12.8 96 13 20 nonhygr. T = 4 h. Srf not changed Lu.sub.0.99Ce.sub.0.01Br.sub.3 0.2 20000 7.5 93 7.7 32 nonhygr. T = 4 h. Srf not changed Lu.sub.0.95Ce.sub.0.05Br.sub.3 0.2 27000 6.4 94 6.6 30 nonhygr. T = 4 h. Srf not changed Lu.sub.0.99Ce.sub.0.01I.sub.3 0.1 50000 4.2 56 7.3 27 hygrosc. T = 3 h. Srf clouded, AA Srf structure changed Lu.sub.0.99Ce.sub.0.01I.sub.3 0.4 45000 4.4 96 4.5 30 nonhygr. T = 4 h. Srf not changed Y.sub.0.95Ce.sub.0.05I.sub.3 0.2 42000 4.5 95 4.6 35 nonhygr. T = 4 h. Srf not changed Y.sub.0.95Ce.sub.0.05I.sub.3 0.4 43000 4.6 96 4.7 36 nonhygr. T = 4 h. Srf not changed

TABLE-US-00003 TABLE 3 Radiation Density length, PL output Decay Appli- Material (g/cm.sup.3) X.sub.0 (cm) (Photons/MeV) (ns) cation NaI:Tl 3.67 2.59 38000 230 General purpose CsF 4.11 2.23 2000 2.8 CsI:Tl.sup.+ 4.53 1.86 59000 1050 X-CT CsI 4.51 1.85 30* 6, 35 Bi.sub.4Ge.sub.3O.sub.12 7.13 1.12 8200 300 PCT, NP, HE CdWO.sub.4 7.68 1.06 15000 5000 X-CT Gd.sub.2SiO.sub.5:Ce 6.71 1.38 10000 60 PET Lu.sub.2SiO.sub.5:Ce 7.4 1.14 30000 40 PET PbWO.sub.4 8.2 0.92 490 10 HE NP: Nuclear physics experiment HE: High energy physics experiment *Faster decay component .sup.+Slight hygroscopicity

TABLE-US-00004 TABLE 4 LFS scintillation crystals: Industry product comparison Crystal* Parameter Tl:NaI BGO LSO GSO LYSO LFS-3 LFS-7 LFS-8 Density, g/cm.sup.3 3.67 7.13 7.4 6.71 7.1 7.35 7.4 7.4 Effective at. number 51 74 66 57 66 64 64 64 Attenuation length, cm 2.6 1.11 1.14 1.38 1.12 1.15 1.12 1.14 Decay constant, ns 230 300 40 30-60 41 25-33 30-35 12-25 Max emission, nm 415 480 420 430 420 425 412-416 422 Light yield 100 7-12 40-75 20 70-80 80-85 80-85 80-85 (NaI:Tl = 100%) Refractive index 1.85 2.15 1.82 1.85 1.81 1.81 1.81 1.81 Energy resolution .sup.137Cs, % 8 12-14 10-14 9.5 8.0 8 8 7 Absorbed y-ray 10 10.sup.2-3 .sup.10.sup.8 .sup.10.sup.8-9 .sup.10.sup.8 10.sup.8 10.sup.8 10.sup.8 irradiation dose, rad (?) (?) (7) (6) (7) (2) (7) (7) (rad. Hardness, %/cm).sup. Hygroscopicity strong No No No No No No No Hardness, Moh 2 4.5 5.8 5.7 5.8 5.8 5.8 5.8 Cleavage (100) none none (100) none none none none Boule size, mm 400 600 100 250 75 200 75 150 75 150 90 250 90 250 50 200 *The chemical composition of the competing crystals: BGOBi.sub.4Ge.sub.3O.sub.12, LSOCe:Lu.sub.2SiO.sub.5, GSOCe:Gd.sub.2SiO.sub.5; LYSOCe:Lu.sub.1.8Y.sub.0.2SiO.sub.5 .sup.Induced optical transmission loss after exposure to radiation is a more realistic and quantifiable measure of the radiation hardness than the absorbed radiation dose.

TABLE-US-00005 TABLE 5 Absolute maximum ratings Parameter Symbol Condition Value Unit Supply voltage Vs 6 V Operating temperature Topr No condensation 20 to +60 C. Storage temperature Tstg No condensation 20 to +70 C. Electrical and optical characteristics (Typ. Ta = 25 C., = p, Vs = 5 V, unless otherwise noted Parameter Symbol Condition Min. Typ. Max Unit Spectral response range 320 to 900 nm Peak sensitivity wavelength p 500 nm Photosensitive area size 3 3 mm Pixel pitch 50 m Number of pixels 3600 Temperature stability of Ta = 25 10 C. 5 % output voltage Photon detection efficiency 0.7 1.0 1.3 10.sup.9 V/W Rise time 10% to 90% 9 ns Cutoff High band fc 3 dB 3.5 5 MHz frequency Low band DC Noise equivalent power NEP Dark condition 1.2 2 fW/Hz.sup.1/2 Minimum detection limit Dark condition 2.7 4.5 pW.r.m.s. Maximum output voltage 4.7 V