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Persistent URL	http://purl.org/net/epubs/work/12213723
Record Status	Checked
Record Id	12213723
Title	Precise Instruments for Bunch Charge Measurement
Contributors	A Kalinin (STFC Daresbury Lab.)
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 , STFC , ASTeC-DL
Keywords	ASTeC 2014-2015 , 06 Instrumentation, Controls, Feedback & Operational Aspects , T03 Beam Diagnostics and Instrumentation
Funding Information
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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).	http://jacow.web.…repress/THPME182.PDF		2014