Operation of the CESR-TA vertical beam size monitor at Eb=4GeV

Autor: J. P. Alexander, C. Conolly, Brian Heltsley, Ernest Fontes, A. Lyndaker, J.W. Flanagan, D.P. Peterson, R. Seeley, E. Edwards, David Rubin, N.T. Rider, James Shanks
Rok vydání: 2015
Předmět:
Zdroj: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 798:127-134
ISSN: 0168-9002
DOI: 10.1016/j.nima.2015.07.028
Popis: We describe operation of the CESR-TA vertical beam size monitor (xBSM) with e ± beams with E b =4 GeV. The xBSM measures vertical beam size by imaging synchrotron radiation x-rays through an optical element onto a detector array of 32 InGaAs photodiodes with 50 μm pitch. The device has previously been successfully used to measure vertical beam sizes of 10–100 μm on a bunch-by-bunch, turn-by-turn basis at e ± beam energies of ~2 GeV and source magnetic fields below 2.8 kG, for which the detector required calibration for incident x-rays of 1–5 keV. At E b = 4.0 GeV and B=4.5 kG, however, the incident synchrotron radiation spectrum extends to ~20 keV, requiring calibration of detector response in that regime. Such a calibration is described and then used to analyze data taken with several different thicknesses of filters in front of the detector. We obtain a relative precision of better than 4% on beam size measurement from 15 to 100 μm over several different ranges of x-ray energy, including both 1–12 keV and 6–17 keV. The response of an identical detector, but tilted vertically by 60° in order to increase magnification without a longer beamline, is measured and shown to improve x-ray detection above 4 keV without compromising sensitivity to beam size. We also investigate operation of a coded aperture using gold masking backed by synthetic diamond.
Databáze: OpenAIRE
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