Development of multichannel readout electronics prototype system for TPC detector of CSR External-Target Experiment

We present a multichannel readout electronics prototype system developed for the Time Projection Chamber (TPC) detector of CSR External-Target Experiment (CEE). The whole system consists of two Front-End readout Electronics (FEE) boards, fiber converters, host computers and a trigger fan-out board. A single FEE board is mainly equipped with four SAMPA chips and a Field Programmable Logic Array (FPGA), processing 128 channels of signals from the TPC detector. The SAMPA chips convert the charge signals into digital signals and send them to FPGA for data processing, and then transmit the data to the host computer through a fiber converter. The control commands from the host computer software realize the control of SAMPA and monitor temperature and current. In the dynamic range of input charge from 2 fC to 100 fC, the readout electronics output amplitude linearity is better than 1%. The relative energy resolution of electronics is about 23% at a minimum input charge of 1.4 fC. The test results with TPC illustrate that with a55Fe source, an energy resolution of 28.5% was acquired, and with cosmic rays, the track resolution on the pad plane is less than 390 & mu;m.