Abstract
加速器中電子束的能量是否與加速器的設計值相吻合將影響電子束在加速 器中的射束行為並影響電子束的生命期，因此電子束能量的測量便顯得非 常重要，於是我們希望設計一實驗系統，對電子束能量作快速、準確及線 上的測量。本論文之研究目的為設計一系統以測量加速器中電子束的能量 。測量雷射光子與相對論性電子之康卜吞散射所產生之高能反向散射的加 馬輻射的能量可反推加速器中電子束的能量。此項理論已為人所熟知並加 以應用。本系統包含一個光學系統和一個加馬輻射的偵檢系統；光學系統 中包含一個二氧化碳雷射及一組光學元件，此系統可提供一個最佳條件以 提高散射光子的通量。由二氧化碳雷射與電子經由康卜吞散射所產生之三 百萬電子伏特的高能加馬輻射將以高純鍺偵檢器偵測之。本論文將研究系 統的建立及最佳條件的選擇方法。經由這些研究，電子束能量測量的誤差 將不大於千分之二。雷射與相對論性電子的康卜吞散射所產生可調的準單 色加馬射束除了可用做測量電子束能量、加馬輻射偵檢器的校正及高能的 核反應實驗外，亦可用來做加速器中電子束的檢測。本論文將討論以康卜 吞散射來測量電子束能量的方法及理論，同時基於相對論性康卜吞散射實 驗在應用上的廣範性，而設計一個除了可測電子束能量外，亦可隨時做更 廣範應用的系統。 This paper present the design study of a system to measure the electron beam energy in an accelerator . The method of Compton scattering between the laser photons and the relativistic electrons was used. By knowing the backscattered photon energy, the electron beam energy can be deduced. The scattering mechanism between the laser photons and the relativistic electrons was well known. The optical system for the laser light was designed to match the laser beam and the electron beam in order to enhance the backscattered photon flux. The implementation of the system in the electron beam transport line in SRRC and the optimization method were studied. A pulsed CO2 laser with high peak power was chosen to produce 3MeV backscattered photons that will be detected with a high purity germanium detector(HPGe). The reason of using HPGe and the pridected results was presented. Under this study, 0.2% energy measurement accuracy was expected.