Study of silicon+ 6 LiF thermal neutron detectors: GEANT4 simulations versus real data

Abstract

Research and development on alternative thermal neutron detection technologies and methods are nowadays needed as a possible replacement of 3 He-based ones. Commercial solid state silicon detectors, coupled with neutron converter layers containing 6 Li, have been proved to represent a viable solution for several applications as present in literature. In order to better understand the detailed operation and the response and efficiency of such detectors, a series of dedicated GEANT4 simulations were performed and compared with real data collected in a few different configurations. The results show a remarkable agreement between data and simulations, indicating that the behavior of the detector is fully understood.

Neutron detection devices with 6LiF converter layers

“…8, and such a ratio shows rather clearly that in order to have a good γ/n discrimination the neutron discrimination threshold value should be chosen at 1.5 MeV. However, lower threshold values can be safely employed in applications where there are no high energy gamma rays (as a reference, the γ/n contamination probabilty from 60 Co gamma rays when setting a 1.5 MeV discrimination threshold is ≤ 10 -12 [10]). In Table I we listed the simulated and measured efficiency for the two detectors.The measured data have a low statistical uncertainty, whereas the systematic one is more relevant, especially on the SiLiF64 detector, because of the energy calibration.…”

“…The reliability of this technique, along with a characterization in terms of response, efficiency and gamma sensitivity, was also assessed by means of GEANT4 simulations [10]. The neutron conversion mechanism is based on the well known reaction (1) which is the only possible decay channel following the neutron capture in 6 Li, and is free of gamma rays.…”

Investigation of neutron scattering in the Multi-Blade detector with Geant4 simulations

“…In the past 3 He-based neutron detectors played a key role for thermal and cold neutron detection [11]. Due to the limitations of these detectors in scientific performance and the shortage of 3 He [12,13], the focus of the neutron detector community has shifted to alternative, higherperforming solutions, such as 10 B 4 C-based detectors [14][15][16][17][18][19][20], scintillators [21][22][23][24][25][26][27][28] or 6 LiF-based solid state silicon detectors [29][30][31]. Additionally, it is already proven that 10 B 4 C-based detectors are capable of outperforming 3 He detectors in terms of spurious scattering of neutrons [10,32].…”