Study of silicon photomultipliers (SiPM) with organic scintillator for neutron diagnostics of thermonuclear plasma

Abstract

The spectrometry of neutrons produced by fusion reactions of plasmatic ions is the most powerful neutron diagnostic tool for monitoring reactor operating power, temperature and concentration of ions. Currently, new generations of silicon photomultipliers (SiPMs) are being used in several light detection fields, including nuclear domain; they have performances similar to conventional photomultipliers tubes (PMTs), while benefiting advantages of solid-state technology such as insensitivity to magnetic and electric fields, excellent temperature stability, robustness, low operating voltage, small size, and low cost. Consequently, they could be a useful device in neutron spectrometer based on recoil proton method for neutron diagnostics of hot plasmas. In this paper, we have demonstrated SiPMs capabilities to be used for fast neutron detection as well as their dynamic range for thermonuclear fusion neutron spectrometry (14 Mev). The responses of SiPMs having different sizes of active areas and microcells manufactured by Ketek and SensL have been studied. Excellent pulse shape discrimination of PuBe source radiations by SiPMs combined with a stilbene crystal has been proven; the figure of merit has reached 3.33. The study has also allowed the determination of the size parameters of SiPMs that are suitable for neutron diagnostics of thermonuclear plasmas.