本論文以可辨別來向的渺子探測器為研究目標，先以閃爍體探測器將渺子訊號轉變為電子訊號，在使用FPGA實現渺子探測器的讀取電路。閃爍體探測器中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訊號以利FPGA之接收。 為了能夠辨別渺子是否來自探測器正前方，將兩個探測器間隔30 cm平行擺放，利用渺子進入兩探測器的時間差是否正確來辨別方向，因FPGA本身的時脈頻率不足以解析1 ns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，從而等效於一個1600 MHz的時脈，使解析度達到0.625 ns。在系統驗證方面，先使用Arduino實現具有不同的輸出時間差的脈衝訊號，來驗證時間至數位轉換電路的功能，再將閃爍體探測器與FPGA整合，實際測量不同天頂角度的渺子通量，也驗證了渺子通量隨著角度減少，從而確認探測器成功運作。 ;In this study, a muon detector which can distinguish the direction of muon is proposed. First, the scintillator detector is used to convert the muon signal into an electronic signal, which is then processed by the readout circuit realized in FPGA. Each scintillator detector include a plastic scintillator and a silicon photomultiplier chip. As the muon passes through the plastic scintillator, it deposits part of its energy in the scintillator. Some fraction of that energy gets converted into photons, which is then converted to a detectable electronic pulse by the silicon photomultiplier chip. The electronic pulse is amplified and converted into a digital signal for the FPGA to receive. In order to identify whether the muons come from the front side of the detector, two scintillator detectors are placed in parallel at a distance of 30 cm, and the time difference between the muons entering the two detectors is used to identify the direction of muon. In order to distinguish the 1-ns time difference between the two detectors, a multi-phase time-to-digital conversion circuit is realized in FPGA to achieve the desired time resolution. Specifically, the clock frequency is multiplied from 100 MHz to 400 MHz, and it is divided into four phases, which becomes equivalent to a clock frequency of 1600 MHz and reaches a resolution up to 0.625 ns. The proposed scintillator detector is first verified using a pulse generator based on Arduino. It is then used to measure the muon flux at different zenith angles. The measured muon flux decreases with the zenith angle as predicted, and this confirms the proper functioning of the proposed muon detector.
