Crystal barrel

Crystal-Barrel is a detector that was developed for particle physics investigations. The main component of Crystal barrel detector is a calorimeter consisting of 1380 CsI (Tl) (crystals, which barrel-shaped engl. Barrels) are arranged around a reaction target. The solid angle coverage is 98% of . The detector is particularly suitable for the detection of photons that arise as decay products of the neutral pions in the reaction . ${\displaystyle 4\pi }$ ${\displaystyle \pi ^{0}\rightarrow \gamma \gamma }$

history

The detector was built at CERN in the mid- 1980s . From 1989 onwards it was used at the Low Energy Antiproton Ring (LEAR) to investigate the spectrum of mesons in proton - antiproton annihilation at rest and in flight (Crystal Barrel Experiment, PS197).

The detector has been in operation at the ELSA electron stretcher system in Bonn since 2000 and is used there for baryon spectroscopy in combination with other detectors (CB-ELSA, CB-TAPS and CB-Transregio). After a rebuilding phase, data has been taken again since the beginning of 2007, including as a double polarization sexperiment with a polarized photon beam and a polarized frozen spin butanol target.

In the years 2015 to 2017 there was a major update of the detector electronics. Electronics with avalanche photodiodes (APD) to detect the scintillation light of the crystals replaced the previous electronics with PIN photodiodes . Data taking started in 2017.

Web links

• Publications CBELSA / TAPS
• Suggestion of the experiment (PDF file; 4.36 MB)
• PS197 documents on the CERN server
• Carnegie Mellon University Crystal Barrel Server
• Main page of the Crystal-Barrel Experiment from 2000 at the University of Bonn