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Persistent URL http://purl.org/net/epubs/work/12213723
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Record Id 12213723
Title Precise Instruments for Bunch Charge Measurement
Contributors
Abstract For the pulse charge q injected into a capacitor of a parallel resonating circuit, the oscillation voltage V on a series resistor R is V=qwRexp(–wt/2Q)sin(wt–1/2Q), t>?, where w is the resonance frequency, Q>>1 is the quality factor and ?<<1/w is the pulse length. Of the two main parameters, R is known, and w can be found directly from the signal above. The quality factor contribution is low, and its rough estimation is sufficient to retain voltage accuracy. The observations above open a possibility of precise bunch charge measurement. We describe a bunch charge monitor that is a cavity with a lump capacitor as a low impedance coaxial line connected to a gap in the vacuum pipe. An LC electronic circuit is also presented. It integrates the single bunch current delivered by a Faraday Cup, or a Wall Current Monitor, or a Fast Current Transformer. The circuit has w~30MHz, Q~20, and with a Faraday Cup, the lower range is 10pC/V and the noise floor is about 20fC. Several such circuits are in use on the VELA injector in Daresbury Laboratory.
Organisation ASTeC , CI , STFC , CLARA , ASTeC-DL
Keywords ASTeC 2014-2015 , 06 Instrumentation, Controls, Feedback & Operational Aspects , T03 Beam Diagnostics and Instrumentation
Funding Information
Related Research Object(s):
Licence Information: Creative Commons Attribution 3.0 Unported (CC BY 3.0)
Language English (EN)
Type Details URI(s) Local file(s) Year
Paper In Conference Proceedings In 5th International Particle Accelerator Conference (IPAC14), Dresden, Germany, 15-20th June, 2014, (2014): 3703-3705. https://jacow.org…/papers/thpme182.pdf 2014