The Research On The Readout Electronics System Of Detectors In CSR

CSRm internal target experiment facility consists of track detector, time of flight detector, electromagnetic calorimeter, hadronic calorimeter etc. CSRm external target experiment facility consists of start time detector, Multi-wire Drift Chamber, Time of Flight Wall, Neutron Wall, etc. Multi-wire Drift Chamber is used to measure the track of charged particles. Time of Flight Wall is used to measure the flight time of charge particle. Neutron Wall is used to measure the flight time of neutron. This thesis mainly discusses the readout electronics system of Multi-wire Drift Chamber (MWDC), Time of Flight Wall and Neutron Wall. An implement and test of the readout electronics based Time-over-Threshold technique is described in details.Charge measurement and time measurement are two important parts of readout electronics of detector. There are three methods of charge measurement that are charge-to-voltage conversion, wave sampling and charge-to-time conversion. Charge-to-time converter based Time-over-threshold technique has the characteristic of simple circuit, low price and low power. Time measurement includes time discrimination and time to digital converter (TDC). Leading end discriminator is easily realized and integrated. But it has time error because of time walk effect. The error can be corrected by charge measurement. Some types of TDC also are introduced, such as TAC+ADC method, Wilkinson TDC, vernier TDC and counter TDC. HPTDC developed by CERN is a counter TDC with very high resolution and is suitable for particle physics experiment.SFE16 is a 16-channel integrated ASIC based Time-over-Threshold technique. Each channel of SFE16 consists of a charge sensitive preamplifier, a pole-zero stage, two selectable filters, an amplifier, a discriminator and a "LVDS compatible" current driver. The output pulse width is a function of input charge.The readout electronics of MWDC uses SFE16 to implement time measurement and charge measurement. The front-end boards with SFE16, realizing the MWDC signal preamplification, shaping and discrimination, will be mounted on the detector. The front-end boards connected to 64-channel time measurement board through differential cables. 64-channel board adopts HPTDC and is installed in PXI crate. The measurement result is transferred to computer through PXI bus.Time of Flight Wall and Neutron Wall both use fast plastic scintillator detectors and phototubes. The readout electronics of them also use Time-over-Threshold technique. To improve time measurement resolution, signal is splitted into two ways, one is sent to leading end discriminator and HPTDC to get precise flight time. The other is sent to SFE16 chip and HPTDC to measure the charge of signal that is used to correct time-walk error. The 8-channel electronics are integrated in one PXI module of 3U size. The measurement result is transferred to computer through PXI bus.The test of readout electronics will give time and charge measurement performance. Test can be divided into three steps that are electronics test in lab, detector and readout electronics combined test, field test. Electronics test uses signal from signal generator to test the performance of readout electronics in lab. For combined test, detector and readout electronics is combined into a test platform. Signal from detector is used to test the performance of the platform. Field test gives the performance of the whole system under real work environment.