Test of a ^3 He neutron detector readout electronics prototype for CSNS multipurpose physics neutron diffractometer

Background Large areas of ^3 He neutron detector array and corresponding readout electronics are used in the MPI built at China Spallation Neutron Source (CSNS) to measure the position and flight time of scattered neutrons, and MPI has a high requirement for the position resolution of ^3 He neutron detector. A ^3 He neutron detector readout electronics prototype composed of two front-end boards and one digital readout board is designed to meet the above requirements. Purpose Testing the whole readout electronics system before its mass production to ensure it can run correctly and fulfill the functional and performance requirements. Methods The test of the readout electronics prototype is implemented in the laboratory, and a signal generator is used to generate electronic signals instead of actual neutron signals. The position resolution test of the readout electronics prototype with ^3 He tubes is carried out in the No. 20 beamline measurement room of CSNS. Results and Conclusion The functional and performance tests in the laboratory state that the readout electronics prototype can fulfill the readout requirements. The typical value of charge resolution is 0.85 fC; the integral nonlinearity of charge is 0.094 % in the input charge range from 100 to 800 fC. The position resolution test result of the prototype with ^3 He tubes is better than the design requirement of 10 mm and also quite good compared with that of some other commercial products. These tests provide a reliable basis for the mass production of the readout electronics prototype.