Development of an FPGA-Based Readout System and Functional Characterization of a Custom NSX1 ASIC for X-ray instrumentation

We developed an FPGA-based readout system for a front-end ASIC (NSX1) with 64 channels to read out a large- area silicon drift detector used in X-ray detection instruments such as the Wide Field Monitor module for the STROBE-X mission concept. The FPGA acts as a central controller for the NSX1 configuration, implementing trigger handling and event sequencing, precise event timestamping, control of an external ADC for digitization, and data transfer to the host PC. The system enables comprehensive ASIC characterization; here, we demonstrate preliminary ASIC functionality and characterization tests using a calibrated pulser for two programmable linear gain responses of 375 mV/fC and 750 mV/fC. These preliminary results validate the low-noise performance of the NSX1 ASIC and demonstrate successful integration of the DAQ system.