Compact Time-of-Flight Neutron Spectrometer with Digital Signal Processing

A compact time-of-flight neutron spectrometer was developed as a part of the BM@N setup at the Nuclotron accelerator (JINR). The aim of the spectrometer is study of neutron emission from target spectator decay in heavy-ion collisions at 2–4 A GeV. The neutron spectra are measured at large angles in the energy range of 2–200 MeV using small flight path of 20–30 cm. Neutron detectors are based on stilbene scintillators coupled with four silicon photomultipliers. The characteristics of the spectrometer were studied with a beam of 3.8 A GeV Xe ions bombarded a CsI target. The obtained time resolution of the detectors is σt ≈ 110–120 ps. A high degree of gamma-quanta suppression was achieved by the pulse shape discrimination method with a factor FOM ≥ 2.