Precise calibration of cavity forward and reflected signals using low-level radio-frequency system

作     者：Jin-Ying Ma Feng Qiu Long-Bo Shi Zheng-Long Zhu Tian-Cai Jiang Zong-Heng Xue Ke-An Jin Qi Chen Cheng-Ye Xu Xing-Hao Ding Zheng Gao Lie-Peng Sun Gui-Rong Huang Yuan He Jin-Ying Ma;Feng Qiu;Long-Bo Shi;Zheng-Long Zhu;Tian-Cai Jiang;Zong-Heng Xue;Ke-An Jin;Qi Chen;Cheng-Ye Xu;Xing-Hao Ding;Zheng Gao;Lie-Peng Sun;Gui-Rong Huang;Yuan He

作者机构：Institute of Modern PhysicsChinese Academy of SciencesLanzhou 730000China School of Nuclear Science and TechnologyUniversity of Chinese Academy of SciencesBeijing 100049China 

出 版 物：《Nuclear Science and Techniques》 (核技术（英文）)

年 卷 期：2022年第33卷第1期

页      面：35-43页

核心收录：

学科分类：080903[工学-微电子学与固体电子学] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 082701[工学-核能科学与工程] 0827[工学-核科学与技术] 

基　　金：supported by the project of “studies of intelligent LLRF control algorithms for superconducting RF cavities(No.E129851YR0)” 

主　　题：Forward and reflected signals Measurement Calibration 

摘      要：Precise measurements of the cavity forward(Vf)and reflected signals(Vr)are essential for characterizing other key parameters such as the cavity detuning and forward *** practice,it is challenging to measure V_(f) and V_(r) precisely because of cross talk between the forward and reflected channels(e.g.,coupling between the cavity reflected and forward signals in a directional coupler with limited directivity).For DESY,a method based on the cavity differential equation was proposed to precisely calibrate the actual V_(f) and V_(r).In this study,we verified the validity and practicability of this approach for the Chinese ADS front-end demo superconducting linac(CAFe)facility at the Institute of Modern Physics and a compact energy recovery linac(cERL)test machine at *** the CAFe facility,we successfully calibrated the actual V_(f) signal using this *** result demonstrated that the directivity of directional couplers might seriously affect the accuracy of V_(f) *** the cERL facility,we calibrated the Lorentz force detuning(LFD)using the actual *** study confirmed that the precise calibration of V_(f) significantly improves the accuracy of the cavity LFD measurement.