Operation Performance Evaluation of Accelerator Based on Cluster Analysis of Bunch-by-Bunch Diagnostic Data
X. Yang
SINAP, Shanghai, People’s Republic of China
Y.B. Leng
USTC/NSRL, Hefei, Anhui, People’s Republic of China
Y.M. Zhou
SARI-CAS, Pudong, Shanghai, People’s Republic of China
In order to improve the operating performance of the particle accelerator, it is better to develop a toolkits to monitor and analyze the sub-health state of the facility in addition to ensuring the stability of basic parameters such as beam current, life, transverse size, longitudinal length and orbit. The 3D bunch-by-bunch position measurement system combined with cluster analysis is a feasible solution for this requirement. HOTCAP is a general solution, which is based on high-speed oscilloscope and developed by SSRF, can deliver charge and absolute 3D position information bunch-by-bunch. Clustering analysis is a method for multidimensional data with complex structure. The data can be aggregated and discover the dependencies between data items. After the SSRF bunch-by-bunch measurement system is put into operation, the data of injection and steady-state operation are continuously accumulated. From it, many information including 3D positions, 3D tunes, filling pattern, refilled charge and the 3D damping times can be extracted. In this paper, based on the operational data of SSRF and the cluster analysis, operational status of the storage ring and injector is evaluated.
A Novel Cavity BPM Electronics for SHINE Based on RF Direct Sampling and Processing
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L.W. Lai, S.S. Cao, X.Q. Liu, Y.M. Zhou
SARI-CAS, Pudong, Shanghai, People’s Republic of China
J. Chen
SSRF, Shanghai, People’s Republic of China
R. Meng
SINAP, Shanghai, People’s Republic of China
Funding:Work supported by The National Science Foundation of China (Grant No.12175293). Youth Innovation Promotion Association, CAS (Grant No. 2019290) A RF direct sampling beam signal processor has been developed in SSRF. It mainly consists of four channels RF direct sampling ADCs and a SoC FPGA. The ADC is 9GHz bandwidth and 2.6GHz sampling rate. A prototype of RF module contains band pass filter, low noise ampli-fier and step attenuator has been designed for SHINE cavity BPM system. Then a novel cavity BPM electronic including the processor and the RF module has been built for SHINE. The performance of the electronic has been analyzed and evaluated in lab. The amplitude relative error is 2.0×10-4,which is better than the required 1×10-3 on cavity BPM system. The phase error is 14fs, also bet-ter than the requirement of RF BAM system. The algorithm and the implementation in FPGA have been introduced. Corresponding author: lailw@sari.ac.cn
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Longitudinal Parameter Measurement System Based on Time-Frequency Domain Joint Analysis
HS. Wang, Y.M. Zhou
SSRF, Shanghai, People’s Republic of China
Y.B. Leng
USTC/NSRL, Hefei, Anhui, People’s Republic of China
X. Yang
UCAS, Beijing, People’s Republic of China
This paper proposes a novel technique for measuring longitudinal bunch length by performing spectral analysis on the beam signals to extract the bunch length information for each bunch and each turn. A high-speed oscilloscope is used to capture original button signal with more than 7000 turns information and an offline Python script is used to retrieve bunch length and phase information. A streak camera is used to calibrate the transfer function of the acquisition system. Experiments were carried out at the Shanghai Synchrotron Radiation Facility and the Hefei Light Source by capturing the electrode signals with an oscilloscope during single bunch injection and harmonic cavity tuning in the storage ring. The calibrated longitudinal bunch length measurement system yielded favorable results, with a larger dynamic range and higher time resolution compared to the streak camera. In the future, the system has the potential to be transplanted into a processor to achieve online longitudinal beam measurement for each bunch.
