射頻偏轉腔自1960初被提出後，在加速器領域持續的被廣泛使用。對於束長量測，射頻偏轉腔可取得電子束完整縱向外觀、具高解析度、可實現單脈衝量測等特性使其在各大研究中心SLAC、CERN、DESY等不斷被改進及應用於其他實驗，如六維相空間診斷、自由電子雷射X光量測、粒子分離器、產生超短電子脈衝等，現在已成了加速器裝置束流診斷的重要工具。和加速器不同，大部分射頻偏轉腔的工作模態為〖TM〗_11，此模態在近軸處存在橫向磁力，對處於不同微波相位的帶電粒子作用不同的勞倫茲力，藉此使粒子偏離中心軸，達到束長量測的目的。
本研究中，我們以SPARC、SLAC、THU等的駐波結構射頻偏轉腔設計做為參考，依國家同步輻射研究中心所提出VUV/THz FEL 自由電子雷射設施構想的需求，設計一可對光陰極注射器進行束流診斷的2998 MHz、駐波形式、運作在π模的三腔偏轉腔，希望在電子能量為數個MeV下可達到sub-ps的解析長度。
我們從研究偏轉腔的結構和微波特性開始，計算出束流診斷所需的腔體形式、腔體數量和解析度，接著使用CST Microwave Studio作為模擬三維偏轉腔微波特性的工具，利用Eigenmode solver 和 Frequency solver調整腔體及耦合孔尺寸，使每個腔體有相同大小的磁場和工作於正確的頻率。另外使用CST Particle Studio 模擬電子束經偏轉腔的變化。最後製作原型，將其量測結果與理論及模擬比較。模擬的結果顯示，以同步輻射光陰極注射器的電子參數為例，設計出的腔體在輸入功率為1 MW下可以達到約500 fs的解析長度。

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