| dc.description.abstract | This study aims to develop a readout circuit for a muon detector such that it can identify incoming muons from specific directions. The main design goal is to improve the accuracy of direction detection of incoming muons. Specifically, the proposed readout circuit is implemented on a Digilent Cora-Z7 FPGA development board, which is integrated with two muon detector modules based on plastic scintillators and silicon photomultipliers. To improve the accuracy of muon detection, Gray code (an error minimization encoding method) is employed into the counter design of the proposed multi-phase time-to-digital converter. Furthermore, two clock frequencies (i.e., 400 MHz and 100 MHz) are utilized to satisfy the required time resolution (1 ns) while allowing sufficient time for the hardware to perform required calculations, thus reducing system instability caused by metastable states. An edge detection circuit is also used to enable the recording the background muon flux.
To verify the functionality of the readout circuit, we use an Arduino development board and delay lines as a stable signal source for testing. The results show that the accuracy of muon direction detection reaches 92.8%, and the reception accuracy of the testing signal is approximately 98%. We then integrate the muon detector modules with the FPGA readout circuit, and measure the muon flux at different zenith angles. The measured, muon flux decreases with increasing angle, which agrees with the theoretical model. In addition, we perform muon flux measurements on different floors of the building, and the results show that the muon flux decreases as the floor level decreases, which is consistent with expectations. These measured results confirm the successful operation of the proposed muon detector. | en_US |