This paper is devoted to the study of a degradation of CsI(Tl)crystals scintillation characteristics under irradiation with gamma-quanta at the uniformly distributed absorbed dose up to 3700 rad. The sample set consisted of 25 crystals of 30 cm long having a truncated pyramid shape and 30 rectangular crystals of the same length. A large difference in the light output deterioration caused by the radiation was observed for the samples of the same shape. A substantial dependence of the average light output loss from the sample shape is seen as well. On the other hand, the crystals from the same ingot behave very similarly under irradiation.
Ensuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered.
Searches for weakly interacting massive particles(WIMP) can be based on the dete ction of nuclear recoil energy in CsI(Tl) crystals. We demonstrate that low energy gamma rays down to few keV is detected with CsI(Tl) crystal detector. A clear peak at 6 keV is observed using X-ray source. Good energy resolution and linearity have been achieved down to X-ray region. In addition, we also show that alpha particles and gamma rays can be clearly separated using the different time characteristics of the crystal.
To efficiently detect energetic light charged particles, it is common to use arrays of energy-loss telescopes involving two or more layers of detection media. As the energy of the particles increases, thicker layers are usually needed. However, carrying out measurements with thick-telescopes may require corrections for the losses due to nuclear reactions induced by the incident particles on nuclei within the detector and for the scattering of incident particles out of the detector, without depositing their full energy in the active material. In this paper, we develop a method for measuring such corrections and determine the reaction and out-scattering losses for data measured with the silicon-CsI(Tl) telescopes of the newly developed HiRA10 array. The extracted efficiencies are in good agreement with model predictions using the GEANT4 reaction loss algorithm for Z=1 and Z=2 isotopes. After correcting for the HiRA10 geometry, a general function that describes the efficiencies from the reaction loss in CsI(Tl) crystals as a function of range is obtained.
The electromagnetic calorimeter of PANDA at the FAIR facility will rely on an operation of lead tungstate (PWO) scintillation crystals at temperatures near -25 deg.C to provide sufficient resolution for photons in the energy range from 8 GeV down to
10 MeV. Radiation hardness of PWO crystals was studied at the IHEP (Protvino) irradiation facility in the temperature range from room temperature down to -25 deg.C. These studies have indicated a significantly different behaviour in the time evolution of the damaging processes well below room temperature. Different signal loss levels at the same dose rate, but at different temperatures were observed. The effect of a deep suppression of the crystal recovery process at temperatures below 0 deg.C has been seen.
CALIFA is the high efficiency and energy resolution calorimeter for the R3B experiment at FAIR, intended for detecting high energy light charged particles and gamma rays in scattering experiments, and is being commissioned during the Phase-0 experiments at FAIR, between 2018 and 2020. It surrounds the reaction target in a segmented configuration with 2432 detection units made of long CsI(Tl) finger-shaped scintillator crystals. CALIFA has a 10 year intended operational lifetime as the R3B calorimeter, necessitating measures to be taken to ensure enduring performance. In this paper we present a systematic study of two groups of 6 different detection units of the CALIFA detector after more than four years of operation. The energy resolution and light output yield are evaluated under different conditions. Tests cover the aging of the first detector units assembled and investigates recovery procedures for degraded detection units. A possible reason for the observed degradation is given, pointing to the crystal-APD coupling.