On the performance of the DELPHI hadron calorimeter
Abstract
High energy physics studied at electron-positron colliders is reviewed. The principles of hadronic energy measurement in experimental high energy physics are introduced. The large electron-positron storage ring (LEP) under construction at CERN is presented together with its experimental program, including the DELPHI experiment. The design and operation of the DELPHI hadron calorimeter are outlined. The expected performance of the calorimeter was studied by exposing a small prototype, of 1 cu m, to hadron and muon beams. The energy resolution is 80 pct per sq rt E. A combination of a lead-glass electromagnetic calorimeter and the hadron calorimeter prototype gives a resolution of 45 pct for 9 GeV/c pions, whereas the hadron calorimeter alone measures the energy with a 35 pct resolution. Dead-space effects were also studied, to assess resolution degradation in the center of the barrel where inactive detector ends are staggered. The FWHM of the measured signal increases from 50 pct to 60 pct for a 37.5 GeV pion beam at the center of the staggered dead-space. The performance of the calorimeter in fast muon triggering was studied. The results indicate that a trigger efficiency higher than 90 pct can be reached in the region theta less than 30 deg, except for a small slot (delta theta = 2.96 deg) between the barrel and the end-cap, without the second-level trigger being disturbed by an unacceptable number of false triggers. The efficiency in the very forward region of the end-cap can reach 80 pct or more in the same conditions.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- April 1988
- Bibcode:
- 1988PhDT........16E
- Keywords:
-
- Beam Interactions;
- Calorimeters;
- Collision Parameters;
- Hadrons;
- High Energy Interactions;
- Muons;
- Storage Rings (Particle Accelerators);
- Particle Collisions;
- Prototypes;
- Spectral Resolution;
- Instrumentation and Photography