Integrated Neutron Detector for Handheld Systems

• Published in: IEEE transactions on nuclear science 2013-04, Vol.60 (2), p.903-907
• Main Authors: Glodo, J., Gueorguiev, A., Shirwadkar, U., Hawrami, R., Tower, J., O'Dougherty, P., Shah, K. S.
• Format: Article
• Language: English
• Subjects: Crystals; Detectors; Electron tubes; elpasolite crystals; Energy measurement; Energy resolution; neutron detectors; Neutrons; pulse shape discrimination; radiation detectors; Shape; silicon photomultiplier; {\rm Cs}_{2}{\rm LiYCl}_{6}; {\rm Cs}_{2}{\rm LiYCl}_{6}:{\rm Ce} (CLYC)
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/TNS.2013.2252020

This paper describes detectors comprised of Cs 2 LiYCl 6 :Ce (CLYC) scintillators coupled to silicon photomultipliers (MPPC, Hamamatsu). CLYC has been developed for dual gamma ray and thermal neutron detection. MPPCs are compact detectors with a very thin profile (~2 mm), but also a small active area (6 mm × 6 mm). The combination of both can create a compact replacement of a He-3 tube. Three different crystal sizes were tested: a 5 mm × 5 mm × 5 mm cube, a 1 cm × 1 cm × 4 cm cuboid, and a Ø1 in × 1 in cylinder. All three detectors showed a well-resolved thermal neutron peak with energy resolution of 5.4%, 7%, and 11% (FWHM), respectively. The degradation in larger crystals is due to a mismatch between the coupled crystal face and the active area of the light detector. All detectors showed the 662 keV gamma ray peak from a Cs-137 source, indicating capability for limited gamma ray spectroscopy, with energy resolutions of 10%, 17%, and 26%, respectively. The capability for pulse shape discrimination was shown as well. The efficiency of the detectors was measured against a 10 atm He-3 tube (9 cm 3 volume). The best absolute efficiency was shown by the cylinder detector, next by the He-3 tube (almost the same as the cylinder detector), and finally by the cuboid detector. The latter showed the best neutron count per cm 3 , twice as high as the two other detectors.