The magnetic distortion calibration system of the LHCb RICH1 detector

Abstract

The LHCb RICH1 detector uses hybrid photon detectors (HPDs) as its optical sensors. A calibration system has been constructed to provide corrections for distortions that are primarily due to external magnetic fields. We describe here the system design, construction, operation and performance.

Performance of the LHCb RICH detectors during LHC Run 2

“…A detailed description of the operation and performance of the correction system can be found in ref. [9]. The magnetic distortion maps are one of the largest sources of differences in reconstruction performance between the magnetic field polarities in RICH1.…”

The LHCb RICH system; detector description and operation

“…In the case of RICH 2 the distortions are small and the image calibration took place before the start of data taking in 2010. In RICH 1 there is a system based on LEDs [11] that can be scanned in front of the photon detectors at regular intervals to test the stability of the correction parameters.…”