Performance study of a prototype readout electronics for the time-of-flight detectors of HIAF-HFRS facility

摘要: In the High Energy FRagment Separator (HFRS) at the High Intensity heavy-ion Accelerator Facility, plastic scintillation detectors are used for high-precision time-of-flight (ToF) measurements to identify the secondary ions from the reaction between the primary beam and the target. During the day-one experiments, the readout electronics for the ToF detectors is required to achieve a time resolution of 94 ps (full width at half maximum, FWHM) with a counting rate up to $10^6$ counts per second (cps) and per channel. This study presents a prototype readout electronics for plastic scintillation ToF detectors. The system comprises a constant-fraction discriminator, a level conversion board, and a time digitization board. We developed an octal logic signal adapter to convert nuclear-instrument-module signals into low-voltage-differential-signaling standard. For time digitization, a field programmable gate array is utilized through the internal tapped delay line. The system’s time resolution and counting rate performance were evaluated using a high-precision pulse generator and a picosecond pulsed laser. The test results indicate that the single-channel time resolution is around 24 ps FWHM, with a maximum counting rate of 1.6$\times$10$^6$ cps. The overall average ToF resolution achieves 42 ps FWHM during the laser test at a repetition rate of 1 MHz. These results validate that the developed system meets the requirements of the HFRS beamline for ToF resolution and counting rate.