Most of the neutron spectrometers planned in the China spallation neutron source (CSNS) are based on position-sensitive 3He tube detectors. To reduce the influence of air on neutron scattering experiments, the detector must be placed within a vacuum chamber for this kind of spectrometers. The readout electronics should also be placed within the vacuum chamber, so the number of feed-through cables can be reduced and the signal-to-noise ratio can be improved. The hit position determination of the 3He tube detector is based on the charge division method, which requires the readout electronics has a digitization sampling rate around 40MHz. To operate such readout electronics in vacuum is a challenge since the power consumption is significant and the heat can’t be removed by air convection. In this research, several scenarios are being explored: (1) Replace the discrete front-end with a low-power ASIC; (2) Use the start-of-art low-power ADC chip and FPGA; (3) Clock gating the system to reduce the dynamic power consumption; (4) Use high-efficiency heat dissipation media to effectively conduct the heat to the metal mechanical structure of the 3He tube detectors. A demonstrator based on some of the above methods has been developed and the tested power consumption is 4.4W. An 8-tube readout prototype with all the above methods employed are being developed, hopefully the total power consumption could be lower than 3W, which is sufficient for operation in vacuum.
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