Neutron time-of-flight spectroscopy measurement using a waveform digitizer

Abstract

The photoneutron source (PNS, phase 1), an electron linear accelerator (linac)-based pulsed neutron facility that uses the time-of-flight (TOF) technique, was constructed for the acquisition of nuclear data from the Thorium Molten Salt Reactor(TMSR) at the Shanghai Institute of Applied Physics (SINAP). The neutron detector signal used for TOF calculation, with information on the pulse arrival time, pulse shape, and pulse height, was recorded by using a waveform digitizer (WFD). By using the pulse height and pulse-shape discrimination (PSD) analysis to identify neutrons and γ-rays, the neutron TOF spectrum was obtained by employing a simple electronic design, and a new WFD-based DAQ system was developed and tested in this commissioning experiment. The DAQ system developed is characterized by a very high efficiency with respect to millisecond neutron TOF spectroscopy.

Measurements of the Total Cross section for Thermal Neutrons at PNS

“…The TOF spectrum was only measured in the direction perpendicular to the incident electron beam. The method applied for the n/γ identification for the TOF spectrum calculations was the pulse-shape discrimination (PSD, calculated by using the integral lengths) method [15,20]. The falling edge of the electron GUN RF signal was used as the start signal, and the neutron peak position of the TOF detector was used as the stop signal for the neutron TOF measurement.…”

“…The digitizer houses the optical link interface, which supports a transfer rate of 80 MBytes/s. It is a very high-efficiency DAQ system for millisecond-or second-level neutron TOF spectroscopy, which incorporates data compression, automatic change of the target, automatic alarm of beam loss, and automatic file opening functions [20].…”