Data Acquisition System For CBM-TOF Super-module Quality Control

The Time-of-Flight(TOF)detector in Compressed Baryonic Matter(CBM)experiment utilizes super module detectors to achieve high-density,high-precision particle flight time measurement.The detector technology is based on multi-gap resistive plate chamber.Each super module supports up to 320 channels of high-precision time measurement capabilities,and the data rate will reach up to 6.4Gbps.For the realization of the electronic signal readout and the precise time measurement,several readout ASICs are under development for CBM detecors.The CBM collaboration also proposed a new data acquisition design method based on triggerless concept.In the super module production process,it is important and necessary to do the quality control work for each detector,to ensure that each super module meets the expected requirements before installation.As the current ASICs and readout system for CBM experiment are still in the development process.Therefore,it is necessary to study the readout method for CBM-TOF super module quality control at this stage.Based on the research of the data readout method of existing TOF detectors,a distributed data readout method suitable for super module quality control is proposed in this paper.And a prototype system based on PXI readout crate is designed under this method.Each data readout module in the prototype system is equipped with a Gigabit Ethernet port,data can be parallel transmitted to the back-end computer.After clarifying the system data transmission process,the realization framework of the data acquisition system is given in this paper.The design and realization of the readout software run on SoC and back-end computer are described in detail,including the software development structure,system communication protocols,implementation of key modules,etc.At last,the function and performance of realized software and hardware are tested.Test results show that for a prototype data readout module,the transfer rate can reach to 680Mbps,the clock and trigger module works stably,the realized software can acquire and assemble data correctly,and also control and monitor each part well.The distributed data readout method proposed in this paper and the realized software and hardware prototype can be subsequently used for CBM-TOF super module readout,for the purpose of quality control.For similar experiment with high density,high data rate read-out needs,it can be used as a reference.