A FPGA-based data acquisition system for GEM array detector

In the present study, a data acquisition system for a GEM one-dimensional array detector is presented. The detector system is to measure the trajectory of photoelectrons produced by cosmic rays. The GEM array detector for the present project has 16 signal channels. The front-end unit provides timing signals from trigger units and energy signals from charge sensitive amplifies and pulse shapers. The timing signals and the energy signals are fed to the time-to-digital converter (TDC) units and analog-to-digital converter (ADC) units respectively. The TDC is to measure the time interval between time marks provided by the front-end unit for trajectory information. The measurement of the pulse height for particle energy information is using an amplitude to time convertor (ATC). The designed TDC has a resolution about 2 ns with good linearity.