The Study Of A Fan-in And Delay Module For Mwdc Based On Flash-ADC Acquisition Scheme

The nuclear symmetry energy Esym(ρ)plays an important role in understanding not only the structure and reaction dynamics of nuclear physics,but also many interesting phenomena in astrophysics.However,there are still many we don’t know,especially its behavior with high-density.The Heavy-ion reactions can form the isospin asymmetry of dense matter intimately related to the density dependence of nuclear symmetry energy,offering the most effective means to study this field in terrestrial nuclear laboratories.The Heavy Ion Research Facility in LanZhou-Cooling Storage Ring,or HIRFL-CSR,delivering heavy-ion beams up to 1GeV/u,to be coupled with advanced detectors at its external target experiment called CEE(CSR External Experiment),will contribute to further studies of Esym(ρ).One kind of the tracking detectors of CEE is the MWDC(Multi Wire Drift Chamber)array,which fulfills the measurement of the tracks of charged particles can offer large detection area and higher particle identification ability.In order to improve the integration of readout electronics,based on the Flash-ADC acquisition scheme,a delay and fan-in module has been designed in order to record the signals from MWDC’s X,U and V sense wires simultaneously in one Flash-ADC channel.By this means the total number of channels is reduced by 60%.The original signal from MWDC is so small that we also need a pre-amplifier for the signal processing.The delay fan-in module contains pre-amplifier circuit and delay fan-in circuit.In this paper we designed the circuit boards than test.The performance of this delay fan-in module was tested with a MWDC detector using55 Fe X ray source.The amplitude signal is smeared by less than 1% and the timing signal is smeared by less than 500 ps,corresponding to the position resolution of25μm.Compared with MWDC’s position resolution of 300μm,both specifications shows that the fan-in and delay module can be used in the application of MWDC with the event rate ranging in 1~10 kHz.