Performance of the Electromagnetic Calorimeter of the HERMES Experiment

The performance of the electromagnetic calorimeter of the HERMES experiment is described. The calorimeter consists of 840 radiation resistant F101 lead-glass counters. The response to positrons up to 27.5 GeV, the comparison between the measured energy and the momentum reconstructed from tracking, long-term stability, hadron rejection and neutral meson invariant mass reconstruction are shown.Comment: 22 pages, 13 figures, LaTeX, accepted by NI

Choice and test of the photomultipliers for the Large Angle electromagnetic shower Calorimeter on the CLAS detector at CEBAF

The choice of the photomultipliers for the Large Angle electromagnetic Calorimeter to be installed on the CLAS detector at CEBAF is reported. The results of comparative tests on three different types of tubes are presented; then the CAMAC-based apparatus that was used to measure the most relevant parameters of a large number of photomultipliers of the chosen type is described and results are discussed

LNF-INFN, C.P.13, Via E. Fermi 40 I-00044 Frascati (Roma), Italy

A description of the HERMES electromagnetic calorimeter is given. The measured characteristics on the test beams and after one year data taking are presented. 1 Introduction: the HERMES experiment HERMES is a new experiment at HERA (DESY) designed to study in a precise and complete way the spin structure of the nucleon by deep inelastic scattering of polarized electrons off polarized protons and neutrons 1) . The HERMES detector 2) is installed in the HERA East Hall interaction region. It consists of a spectrometer magnet and a PID detector and is able to measure the scattered electron and the total hadronic final state in a wide kinematic range and with good angular and momentum resolutions. For a detailed description of the experiment see ref. 3). By measuring the cross section asymmetry, i.e. the difference of scattering probabilities of electrons off nucleons with spin parallel or antiparallel to the spin of the incident electrons, HERMES determines the spin structure functions g ..

Performance of the new plastic scintillator NE110A for the CLAS large angle calorimeter

The performance of the new NE110A plastic scintillator has been measured in connection with the construction of the AIACE large angle electromagnetic calorimeter for the CLAS detector at CEBAF. Measurements concerning 2128 scintillator bars 15 mm thick, roughly 10 cm wide and up to 450 cm length are reported. The results show an attenuation length of the order of 400 cm, a light output of 6540 photoelectrons/MeV and a uniformity >98%

Performance of F101 Radiation Resistant Lead Glass Shower Counters.

The performance of F101 lead glass as a Cherenkov radiation material was studied. A 3 × 3 array of 9 × 9 cm2 and 50 cm length counters showed an energy resolution of ≈5.0%E(GeV), good linearity in the energy range from 1 to 25 GeV and π−e rejection of ≈4 × 10−4