A Fully Digital Beam Position and Phase Measurement Electronics for the Proton LINAC in ADS

Abstract:

The beam measurement is essential for an accelerator. In the proton LINAC in China Accelerator Driven Sub-critical system (ADS), a high resolution measurement of beam position and phase is required within one single system. To meet the requirement, this beam position and phase measurement (BPPM) electronics is designed based on a direct RF under-sampling technique, which simplifies both the analog and digital processing circuits. The signals received from the LINAC are narrow pulses with a repetition frequency of 162.5 MHz and a dynamic range more than 40 dB. After analog manipulation, the input RF signals are directly converted to In-phase and Quadrature-phase (IQ) streams through under-sampling based on the high-speed high-resolution Analog-to-Digital conversion technique. All signal processing is integrated in one single FPGA, in which real-time beam position, phase and current can be obtained. A series of simulations and tests have been conducted to evaluate the performance. Initial test results indicate that this system achieves a position resolution better than 20 um and a phase resolution better than 0.1 degree over a 40 dB dynamic range with the bandwidth of 780 kHz, which is well beyond the application requirements.

• Periodical: Applied Mechanics and Materials (Volumes 333-335)
• Pages: 379-388
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.333-335.379
• Online since: July 2013
• Authors: Xiao Fang Hu, Lei Zhao, Xing Shun Gao, Shu Bin Liu, Qi An
• Keywords: ADS, Analog-To-Digital Conversion, Beam Position, Phase Measurement, RF Signal IQ under Sampling

References

[1] Zhao Zhixiang, Xia Haihong: Engineering Science, Vol. 10(2008), pp.66-72.

[2] Lei Zhao, Shubin Liu, Shaochun Tang, Qi An: IEEE Trans. Nucl. Sci., Vol. 57(2010), pp.533-538.

[3] Hao Zhou, Shubin Liu, Lei Zhao, Kai Chen, Han Yan, Qi An: ICEMI. 2009. 5273995. 9th Int. Conf. Electronic Measurement & Instruments, Beijing, China, Aug, 2009, 1045-1051.

[4] Pengda Gu, Zheqiao Geng, Guoxi Pei, et al. RF phasing system for BEPCII linac. 3rd Asian Particle Accelerator Conference, Gyeongju, Korea, Mar 2004, 288-290.

DOI: 10.1109/pac.2005.1591798

[5] Zheqiao Geng, Pengda Gu, Mi Hou, Yanyan Cui: PAC. 2005. 1591798. Particle Accelerator Conference, Knoxville, TN, United states, May 2005, 1-3.

DOI: 10.1109/pac.2005.1591798

[6] S. Sabah, R. Lorenz. Design and Calibration of IQ-Mixers. 6th European Particle Accelerator Conference, Stockholm, Sweden, Jun 1998, 1589-1591.

[7] J. F. Power, J. D. Gilpatrick, M. W. Stettler: Proceedings of the 1997 17th Particle Accelerator Conference, Vancouver, BC, CAN, May 1997, 2041-(2043).

[8] J. Power, M. Stettler: 8th Beam Instrumentation Workshop (BIW 98), STANFORD, CA, MAY 1998, 459-466.

[9] J. Power, J. O'Hara, S. Kurennoy, M. Plum and M. Stettler LANL: PAC. 2001. 986685. Particle Accelerator Conference 2001, Chicago, IL, June 2001, 1375-1377.

[10] Harald Klingbeil: IEEE Trans. Instrum. Meas., Vol. 54(2005), pp.1209-1213.

[11] Peter Forck, Piotr Kowina, Dmitry Liakin in: Beam Position Monitors, CERN Accelerator School on Beam Diagnostics, 2008, 187-228.

[12] Shaochun Tang, Lei Zhao, Shubin Liu, Xinjun Hao, Weihao Wu, and Qi An: IEEE Trans. Instrum. Meas., Vol. 61( 2012), pp.2870-2878.

[13] Rodney G. Vaughan, Neil L. Scott, D. Rod White: IEEE Trans. Signal Process., Vol. 39(1991), p.1973-(1984).

[14] AD9467 datasheet, http: /www. analog. com.

[15] Application Note on Transformers, http: /www. minicircuits. com/app.

[16] TC1-1T+ datasheet, http: /www. minicircuits. com.

[17] Rob Reeder. Transformer-Coupled Front-End for Wideband A/D Converters, http: /www. analog. com/analogdlalogue.

[18] Improving Gain Flatness without Sacrificing Dynamic Performance in High-IF ADCs, http: /pdfserv. maximintegrated. com/en/an.

[19] Brad Brannon, Allen Barlow. Aperture Uncertainty and ADC System Performance, http: /www. analog. com.

[20] Brad Brannon. Sampled systems and the effects of clock phase noise and jitter, http: /www. analog. com.