Developing a direction-sensitive Cerenkov detector for beam monitoring applications

Abstract

The detector protection system used at the Large Hadron Collider to detect upstream beam-gas events is limited in its efficiency due to the very large flux of particles produced in the beam-beam collisions at the center of the detectors. My project is an investigation into the feasibility of developing a direction-sensitive device that can detect particles coming into the detectors from beam-gas interactions while being insensitive to particles coming out of the detectors from beam-beam collisions. Cerenkov detectors are a natural choice for direction-sensitive detector applications as Cerenkov radiation is produced in a forward facing cone by charged particles traveling through a transparent medium faster than the speed of light in that medium. The direction sensitivity of our particular Cerenkov detector was determined by collecting pulse height data from the detector placed at angles of 0 and 180 degrees with respect to an incident particle beam. This testing was carried out with a proton beam at the Fermilab Test Beam Facility. The data was then compared to the result expected based on a Monte Carlo simulation performed using the program Geant4. The detector in the backward orientation was found to have a 98.8 ± 0.2% rejection efficiency, a value which indicates that the detector design is sufficiently direction-sensitive for possible incorporation into the Large Hadron Collider beam monitoring system.