Design of a Readout Circuit Chip for a Cosmic Ray Muon Detector with Multi-Angular Acceptance

A cosmic ray muon is a natural ray source with strong penetrability and has broad application prospects, especially in the monitoring of atmospheric temperature variations. In order to accurately deduce the atmospheric temperature variations, a global cosmic ray monitoring network is needed, and a low-cost, low-power, high-accuracy, efficient, and portable muon detection system is required. In this paper, we present the design of a 32-channel readout circuit chip for a muon detector with multi-angular acceptance. It can detect the information of incident muon rays, including both the arrival time and the pulse width of the signals. A novel readout circuit structure using a digital phase-locked loop (DLL) is proposed to decrease the frequency of the system clock without sacrificing the time measurement accuracy. For an input system clock of 50 MHz, a time resolution of ±1 ns is achieved by using a DLL generating 20 equally delayed clock signals. The designed readout circuit chip follows a 0.18 μm mixed-signal CMOS process, and the simulation results demonstrate the above-mentioned functions and performances.