Fast neutron flux analyzer with real-time digital pulse shape discrimination

• Electronic equipment for measurement of fast neutron flux with stilbene scintillator is presented.
• FPGA-implemented digital pulse-shape discrimination algorithm by charge comparison method is shown.
• Calibration of analyzer was carried out with 137Cs and 252Cf.
• Figures of Merit (FOM) values for energy cuts from 1/8 Cs to 2 Cs are from 1.264 to 2.34 respectively.

Investigation of subthermonuclear plasma confinement and heating in magnetic fusion devices such as GOL–3 and GDT at the Budker Institute (Novosibirsk, Russia) requires sophisticated equipment for neutron-, gamma- diagnostics and upgrading data acquisition systems with online data processing. Measurement of fast neutron flux with stilbene scintillation detectors raised the problem of discrimination of the neutrons (n) from background cosmic particles (muons) and neutron-induced gamma rays (γ). This paper describes a fast neutron flux analyzer with real-time digital pulse-shape discrimination (DPSD) algorithm FPGA-implemented for the GOL–3 and GDT devices. This analyzer was tested and calibrated with the help of 137Cs and 252Cf radiation sources. The Figures of Merit (FOM) calculated for different energy cuts are presented.