THE DESIGN AND INITIAL TESTING OF THE BEAM POSITION MEASUREMENT SYSTEM IN SSRF BASED ON FULLY DIGITAL SIGNAL PROCESSING

Han Yan, Shubin Liu, Kai Chen, Weihao Wu, Lei Zhao, Qi An, Yongbin Leng, Xing Yi, Yingbing Yan, Longwei Lai

Abstract

This fully digital beam position measurement system is designed both for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility (SSRF). The signals received from four position-sensitive detectors (PSD) are narrow pulses with a repetition rate up to 499.654 MHz and a pulse width of around 100 ps, the dynamic range of which could vary over more than 40 dB in machine research. By the employment of the under-sampling technique based on high-speed high-resolution A/D conversion, all the processing procedure is performed fully by the digital signal processing (DSP) algorithms integrated in one single FPGA. A previous incomplete prototype of this system had been designed with simple tests conducted. After debugging and modification, the second version system is designed, and a more systematic test is conducted, which will be presented in details. The initial testing results indicate that this system has achieved a position resolution (at the turn by turn rate of 694 kHz) better than 7 um over the input amplitude range of -40 dBm to 10 dBm.

Keywords

beam position measurement, under-sampling, high-speed high-resolution A/D conversion, fully digital signal processing, SSRF

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DOI

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IMEKO TC

TC4 - Measurement of Electrical Quantities

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