Abstract
The trigger system of the COMPASS experiment at the CERN polarized muon beam is presented. It detects muon scattering events on (polarized) nucleons with a relative energy loss exceeding a selectable value ymin independent of the four-momentum transfer. The requirement of a minimum energy deposit in a hadron calorimeter rejects background events like scattering on electrons, elastic and quasi-elastic radiative events as well as events from beam halo tracks. The trigger system which can be considered as a tagger for quasi-real photon events is now, along with larger trigger hodoscope system for deep inelastic scattering events, in regular use for the measurement of the gluon polarisation ΔG/G.
Original language | English |
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Pages (from-to) | 217-240 |
Number of pages | 24 |
Journal | Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment |
Volume | 550 |
Issue number | 1-2 |
DOIs | |
State | Published - Sep 11 2005 |
Externally published | Yes |
Funding
Supported by the Bundesministerium für Bildung und Forschung.
Keywords
- COMPASS spectrometer
- Calorimeter
- Muon beam
- Polarised deep inelastic lepton scattering
- Scintillators
- Trigger