Radiation-hardness measurements of high OH- content quartz fibres irradiated with 24 GeV protons up to 1.25 Grad

We investigated the darkening of two high OH- content quartz fibres irradiated with 24 GeV protons at the Cern PS facility IRRAD. The two tested fibres have a 0.6 mm quartz core diameter, one with hard plastic cladding (qp) and the other with quartz cladding (qq). These fibres were exposed at about 1.25 Grad in 3 weeks. The fibres became opaque below 380 nm and in the range 580-650 nm. The darkening under irradiation and damage recovery after irradiation as a function of dose and time are similar to what we observed with electrons. The typical attenuation at 455 nm are 1.44 ± 0.22 and 2.20 ± 0.15 dB / m at 100 Mrad for qp and qq fibres, respectively. The maximum damage recovery is also observed near this wavelength. © 2007 Elsevier B.V. All rights reserved.Türkiye Atom Enerjisi Kurumu DE-FG02-91ER 40664, NSF-INT-98-20258 Atomic Energy Regulatory Board 06B302We thank Maurice Glaser responsible of the IRRAD facility who helped us in the installation of our set-up and calibrated the dose received, the PS operators and technicians providing the proton beam, the SPS-PS coordinator and the CMS test beam coordinator. We thank I. Dumanoglu for helpful discussions. We would also like to thank the University of Iowa for their continuing support for this research. This work was supported by the US Department of Energy (DE-FG02-91ER 40664) and NSF (NSF-INT-98-20258) and the Scientific and Technical Research Council of Turkey, TUBITAK, Turkish Atomic Energy Board (TAEK) and Bogazici University Research Fund (Grant no. 06B302)

Design, performance, and calibration of the CMS hadron-outer calorimeter

The Outer Hadron Calorimeter (HCAL HO) of the CMS detector is designed to measure the energy that is not contained by the barrel (HCAL HB) and electromagnetic (ECAL EB) calorimeters. Due to space limitation the barrel calorimeters do not contain completely the hadronic shower and an outer calorimeter (HO) was designed, constructed and inserted in the muon system of CMS to measure the energy leakage. Testing and calibration of the HO was carried out in a 300 GeV/c test beam that improved the linearity and resolution. HO will provide a net improvement in missing E (T) measurements at LHC energies. Information from HO will also be used for the muon trigger in CMS

The CMS barrel calorimeter response to particle beams from 2 to 350 GeV/c

The response of the CMS barrel calorimeter (electromagnetic plus hadronic) to hadrons, electrons and muons over a wide momentum range from 2 to 350 GeV/c has been measured. To our knowledge, this is the widest range of momenta in which any calorimeter system has been studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. The analysis of the differences in calorimeter response to charged pions, kaons, protons and antiprotons and a detailed discussion of the underlying phenomena are presented. We also show techniques that apply corrections to the signals from the considerably different electromagnetic (EB) and hadronic (HB) barrel calorimeters in reconstructing the energies of hadrons. Above 5 GeV/c, these corrections improve the energy resolution of the combined system where the stochastic term equals 84.7±1.6% and the constant term is 7.4±0.8%. The corrected mean response remains constant within 1.3% rms

The CMS barrel calorimeter response to particle beams from 2 to 350 GeV/c

The response of the CMS barrel calorimeter (electromagnetic plus hadronic) to hadrons, electrons and muons over a wide momentum range from 2 to 350 GeV/c has been measured. To our knowledge, this is the widest range of momenta in which any calorimeter system has been studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. The analysis of the differences in calorimeter response to charged pions, kaons, protons and antiprotons and a detailed discussion of the underlying phenomena are presented. We also show techniques that apply corrections to the signals from the considerably different electromagnetic (EB) and hadronic (HB) barrel calorimeters in reconstructing the energies of hadrons. Above 5 GeV/c, these corrections improve the energy resolution of the combined system where the stochastic term equals 84.7±1.6% and the constant term is 7.4±0.8%. The corrected mean response remains constant within 1.3% rms