TY - JOUR
T1 - Evaluation of a LiI(Eu) neutron detector with coincident double photodiode readout
AU - Yang, H.
AU - Menaa, N.
AU - Bronson, F.
AU - Kastner, M.
AU - Venkataraman, R.
AU - Mueller, W. F.
PY - 2011/10/1
Y1 - 2011/10/1
N2 - Previous work showed that enriched 6Li halide scintillation crystal is a good candidate for portable neutron-sensitive detectors. Photodiode readout is a good alternative to PMT in compact devices. These detectors are often required to work in presence of a strong gamma background. Therefore, great discrimination against gamma rays is crucial. Because of the high Q-value of the 6Li(n,α)3H reaction, the light yield of a neutron capture signal corresponds to 34 MeV gamma equivalent in spite of the quenching effect of heavily charged particles. As a result, energy discrimination is quite effective against gamma signals generated in thin crystals. However, direct gamma interactions inside the photodiode can create pulses whose amplitude is large enough to interfere with thermal neutron peak. This study shows an innovative design based on coincident readout to solve this problem. In this design, two photodiodes are attached on both sides of the LiI crystal. The output signal is only accepted when both photodiodes give out coincident output. The method is proved to effectively suppress background in the neutron window in a 420 mR/h 137Cs field down to the level of natural background.
AB - Previous work showed that enriched 6Li halide scintillation crystal is a good candidate for portable neutron-sensitive detectors. Photodiode readout is a good alternative to PMT in compact devices. These detectors are often required to work in presence of a strong gamma background. Therefore, great discrimination against gamma rays is crucial. Because of the high Q-value of the 6Li(n,α)3H reaction, the light yield of a neutron capture signal corresponds to 34 MeV gamma equivalent in spite of the quenching effect of heavily charged particles. As a result, energy discrimination is quite effective against gamma signals generated in thin crystals. However, direct gamma interactions inside the photodiode can create pulses whose amplitude is large enough to interfere with thermal neutron peak. This study shows an innovative design based on coincident readout to solve this problem. In this design, two photodiodes are attached on both sides of the LiI crystal. The output signal is only accepted when both photodiodes give out coincident output. The method is proved to effectively suppress background in the neutron window in a 420 mR/h 137Cs field down to the level of natural background.
KW - Coincidence readout
KW - Gamma discrimination
KW - LiI
KW - Thermal neutron detection
UR - https://www.scopus.com/pages/publications/80052943940
U2 - 10.1016/j.nima.2010.08.119
DO - 10.1016/j.nima.2010.08.119
M3 - Article
AN - SCOPUS:80052943940
SN - 0168-9002
VL - 652
SP - 364
EP - 369
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
IS - 1
ER -