Large area 3He tube array detector with modular design for multi‑physics instrument at CSNS

The characteristics of the MPI detector have been investigated through Monte Carlo (MC) simulations by Geant4 and experimental measurements. The results suggest that the detectors are highly efficient in the range of wavelength of the MPI, and the efficiency over 25% is achievable for above 0.1 Å neutrons. A minimal position resolution of 6.4 mm (FWHM) along the tube length was achieved at a working voltage of 2200 V, and a deviation below 2 mm between the real position and the measured position was attained in the beam experiment.

The detector module exhibits good consistency and an excellent counting rate capacity of up to 80 kHz, which satisfies the requirements of experiments with a high event rate. Observations of its operation over the past year have shown that the detector works steadily in sample experiments, which allows the MPI to successfully serve the user program.