Application of a modified iterative learning control algorithm for superconducting radio-frequency cavities

Transient beam loading, which causes cavity gradient fluctuation, is becoming a major concern for the stable operation of the high current superconducting radio-frequency (SRF) accelerators. Iterative learning control (ILC) is an effective algorithm aiming to improve systems operated in repetitive m...

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Bibliographic Details
Published in:Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 1026; p. 166237
Main Authors: Xu, Chengye, Zhu, Zhenglong, Qiu, Feng, Jiang, Tiancai, Chen, Qi, Gao, Zheng, Ma, Jinying, Shi, Longbo, Jiang, Guodong, Xue, Zongheng, Jin, Kean, Sun, Liepeng, Wang, Zhijun, Huang, Guirong, He, Yuan
Format: Journal Article
Language:English
Published: Elsevier B.V 01.03.2022
Subjects:
CAFe
CiADS
Iterative learning control (ILC)
Low-level radio-frequency (LLRF)
Superconducting
CAFe
CiADS
Superconducting
Iterative learning control (ILC)
Low-level radio-frequency (LLRF)
ISSN:0168-9002, 1872-9576
Online Access:Get full text
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Summary:Transient beam loading, which causes cavity gradient fluctuation, is becoming a major concern for the stable operation of the high current superconducting radio-frequency (SRF) accelerators. Iterative learning control (ILC) is an effective algorithm aiming to improve systems operated in repetitive mode. This ILC technique was successfully introduced to the low-level radio-frequency (LLRF) control in accelerators to compensate for the field fluctuation caused by repetitively pulsed beam. The modern LLRF system prefers to use the FPGA-based hardware platform to realize a real-time control framework. However, considering the algorithm complexity and the hardware cost, the ILC algorithm is usually implemented outside FPGA. This practice would decrease the real-time ability of the control system. In this paper, we present a modified ILC algorithm that can be implemented inside FPGA. The key idea of our method is to simplify the beam profile using a rectangular pulse. The method was demonstrated in the SRF cavities at Chinese Accelerator driven system Front-end demo SRF linac (CAFe). The experimental results in the CAFe beam-commissioning confirmed that the beam-induced gradient fluctuation is successfully suppressed.
ISSN:0168-9002
1872-9576
DOI:10.1016/j.nima.2021.166237