Simulation for reducing the γ-ray background in the EAR2 at n_TOF

The n TOF (neutron time-of-flight) facility at CERN is an experimental facility for precise measurements of neutron-induced reaction cross sections over a wide range of neutron energies. Fig. 1 shows the layout of the n TOF facility. A pulsed 20 GeV/c proton beam from the Proton Synchrotron (PS) at CERN hits a Pb spallation target, producing various secondary particles. Of the secondary particles produced, neutrons are the most abundant particles and are used to measure neutron capture cross sections in the experimental area at n TOF. As shown in Fig. 1, the n TOF facility has two beamlines: EAR1 and EAR2. In this study, we focused on the EAR2 beamline, which extends vertically from the spallation target.