A calibration system for Compton polarimetry at e(+) e(-) linear colliders

作者：Vormwald B^*; List J; Vauth A

来源：Journal of Instrumentation, 2016, 11(01): P01014.

DOI：10.1088/1748-0221/11/01/P01014

• Detector alignment and calibration methods (lasers sources, particle-beams)
• Beam-line instrumentation (beam position and profile monitors
• beam-intensity monitors
• bunch length monitors)
• Cherenkov detectors
• Photon detectors for UV, visible and IR photons (vacuum) (photo-multipliers, HPDs
• others)

Polarimetry with permille-level precision is essential for future electron-positron linear colliders. Compton polarimeters can reach negligible statistical uncertainties within seconds of measurement time. The dominating systematic uncertainties originate from the response and alignment of the detector which records the Compton scattered electrons. The robust baseline technology for the Compton polarimeters foreseen at future linear colliders is based on an array of gas Cherenkov detectors read out by photomultipliers. In this paper, we will present a calibration method which promises to monitor nonlinearities in the response of such a detector at the level of a few permille. This method has been implemented in an LED-based calibration system which matches the existing prototype detector. The performance of this calibration system is sufficient to control the corresponding contribution to the total uncertainty on the extracted polarisation to better than 0.1%.

• 出版日期2016-1