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@inproceedings{hulsart:ibic2021-mopp20,
author = {R.L. Hulsart and R.J. Michnoff and S. Seletskiy and P. Thieberger},
title = {{Beam Position Monitor Calibration by Rapid Channel Switching}},
booktitle = {Proc. IBIC'21},
pages = {84--87},
eid = {MOPP20},
language = {english},
keywords = {electron, electronics, controls, hardware, experiment},
venue = {Pohang, Rep. of Korea},
series = {International Beam Instrumentation Conference},
number = {10},
publisher = {JACoW Publishing, Geneva, Switzerland},
month = {10},
year = {2021},
issn = {2673-5350},
isbn = {978-3-95450-230-1},
doi = {10.18429/JACoW-IBIC2021-MOPP20},
url = {https://jacow.org/ibic2021/papers/mopp20.pdf},
note = {https://doi.org/10.18429/JACoW-IBIC2021-MOPP20},
abstract = {{One of the requirements for low-energy RHIC electron cooling (LEReC) is a small relative angle between the ion and electron beams as they co-propagate. In order to minimize relative electron-ion trajectories angle, BPM measurements of both beams must be very accurate. Achieving this requires good electronic calibration of the associated cables and RF components, due to their inherent imperfections. Unfortunately, these are typically frequency dependent, especially in the RF filter and amplifier stages. The spectral content of the ion vs. electron bunch signals varies significantly, presenting a calibration challenge, even when using the same sampling channels and electronics to measure both beams. A scheme of rapidly swapping the BPM signals from the pickup electrodes between the two signal cables (and sampling channels), using switches installed near the BPM was implemented to combat these calibration is-sues. Bias in each signal path appears as an offset which has an equal and opposite component when the cables are reversed. Taking the average of the two measurements with the channels in normal and reverse positions reduces this offset error. Successful transverse cooling of the RHIC ion beam has been verified after using this switching technique to provide continuous calibration of the BPM electronics [1]. Details of the processing hard-ware and switch control methodology to achieve this result will be discussed.}},
}