本論文以FPGA做為渺子探測器的讀取電路實現渺子探測器，配兩個間距60cm的渺子探測器模組，目標為提升辦別渺子來向之正確率、記錄渺子背景值與提高渺子量測的角解析度。首先，閃爍體探測器包含塑膠閃爍體及矽光電倍增管，使用塑膠閃爍體將渺子輻射能量轉換為光子，接著在利用矽光電倍增管將光子轉換為電子脈衝訊號，最後再藉由比較器電路將電子脈衝訊號放大並轉換為數位電子訊號以利FPGA接收。 為了能夠辨別渺子的來向，將兩個探測器間隔60 cm擺放，利用渺子進入兩探測器的相位差來辨別方向，因FPGA本身的時脈不足以解析其時間差，故設計時間至數位轉換電路來增加時間解析度。本研究選擇以鎖相迴路為基礎之時間至數位轉換電路，將時脈從100 MHz倍頻至400 MHz並切分為四個相位，可以等效成一個1600 MHz的時脈，使解析度達到0.625 ns。最後使用Arduino及不同長度的單芯線產生不同的輸出時間差，來驗證時間至數位轉換電路的功能，也將閃爍體探測器及FPGA整合，實際測量不同角度及不同障礙物下的渺子通量，驗證了渺子通量會隨著角度增加以及隨障礙物增加(樓層降低)而減少。 ;This research presents an FPGA-based readout circuit for a muon detection system, comprising two muon detector modules spaced 60 cm apart, enabling measurement of muon flux coming from specific directions. The primary objectives include improving the accuracy of muon direction identification, recording background muon flux, enhancing angular resolution of muon detection, and monitoring temperature and humidity at the same time. Each muon detector module integrates a plastic scintillator and a silicon photomultiplier (SiPM). The plastic scintillator converts muon radiation into photons, which are subsequently transformed into electrical pulse signals by the SiPM. These analog output of SiPM are then amplified and digitized using a comparator circuit before sending to the FPGA for signal analysis. To determine the direction of incoming muons, the proposed system calculates the time difference between muon events recorded by the two muon detectors spaced 60 cm apart. A phase-locked loop (PLL)-based time-to-digital converter (TDC) is implemented on the FPGA, translating the measured time difference into a corresponding phase difference of the clock signals. By multiplying the clock frequency from 100 MHz to 400 MHz and subdividing it into four phases, an effective clock frequency of 1600 MHz is achieved, resulting in a time resolution of 0.625 ns. Muon flux measurements under varying zenith angles and environmental conditions were conducted and subsequently compared with theoretical predictions, validating the performance and reliability of the proposed muon detection system.
