Improved light charged particle identification method using grid ionization chamber at CSNS Back-n White Neutron...

The Light-Charged Particle Detector Array (LPDA) operates at the Back-n white neutron source of the China Spallation Neutron Source (CSNS). The high neutron flux at Back-n causes event pile-up in the grid ionization chamber (GIC) of the LPDA. The particle identification method previously used for the ⁶Li(n, t)⁴He reaction channel ignored the events of two tritons being incident simultaneously, resulting in a systematic underestimation of particle yield. To address this issue, we propose a novel function g(E,R(E)) that relates particle energy E to ionization range R(E), which can be used to extract the proportion of double-triton from statistical distributions. Multi-parameter analysis in the neutron energy region from 0.3eV to 1MeV reveals that the double-triton events, the triton events and the invalid events constitute 3.4%, 94.6% and 2% of the total counts, respectively. This work validates the feasibility of resolving (n, cp) pile-up events under high-flux conditions, offering new approaches for detector designing in high-rate environments such as nuclear reactors or accelerator-driven systems.