Gamma-Ray Induced Radiation Damage in Large Size LSO and LYSO Crystal Samples (original) (raw)
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A Study on Radiation Damage in Large Size LSO and LYSO Crystal Samples
2006 IEEE Nuclear Science Symposium Conference Record, 2006
This paper presents a study on radiation damage effect in large size (2.5×2.5×20 cm 3) LSO and LYSO crystals. Optical and scintillation properties, including the longitudinal transmittance and emission spectra, the light output and light response uniformity with PMT and APD readout, are measured before and after γ-ray irradiations with integrated dosage up to 10 6 rad for three LSO and LYSO samples from different vendors. It was found that the recovery of radiation damage under room temperature is negligible, indicating that radiation damage in LSO and LYSO crystals are not dose rate dependent. It was also found that the overall radiation damage in LSO and LYSO crystals is small as compared to other crystal scintillators commonly used in high energy and nuclear physics experiments.
Gamma ray induced radiation damage in PWO and LSO/LYSO crystals
2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC), 2009
This paper compares-ray induced radiation damage effect in two kinds of heavy crystal scintillators: PWO and LSO/LYSO. Scintillation emission, optical transmission, light output, decay kinetics and light response uniformity were measured for PWO and LSO/LYSO crystal samples of large size before and after-ray irradiations.-ray induced phosphorescence was also measured, and the corresponding readout noise was determined.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007
The high energy and nuclear physics community is interested in fast bright heavy crystal scintillators, such as cerium-doped LSO and LYSO. An investigation is being carried out to explore the potential use of the LSO and LYSO crystals in future physics experiments. Optical and scintillation properties, including longitudinal transmittance, emission and excitation spectra, light output, decay kinetics and light response uniformity, were measured for three long (2.5 Â 2.5 Â 20 cm) LSO and LYSO samples from different vendors, and were compared to a long BGO sample of the same size. The degradation of optical and scintillation properties under gray irradiations and the radiation-induced phosphorescence were also measured for two long LYSO samples. Possible applications for a crystal calorimeter in future high energy and nuclear physics experiments are discussed.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2007
LSO:Ce, LYSO:Ce and GSO:Ce single-crystal scintillator light emission characteristics were studied in the low γ-ray energy range (99mTc source) used in nuclear medical imaging. The absolute luminescence efficiency and the optical emission spectrum of the three scintillators were measured, under γ-ray excitation using an integration sphere coupled to a photomultiplier and an optical spectrometer, respectively. Spectral compatibility of all scintillators to optical sensors was also estimated. The absolute luminescence efficiency of all crystals was found adequately high (8.7 μW m-2/μGy s-1 for GSO:Ce, 15.3 μW m-2/μGy s-1 for LYSO:Ce and 20.0 μW m-2/μGy s-1 for LSO:Ce). Their emission spectra were found compatible (57 94%) to currently employed optical photon detectors.
IEEE Transactions on Nuclear Science, 2000
We measured photoelectron yield, light output, decay times of the light pulses, cerium concentration, energy resolution and time resolution of LSO:Ce manufactured by different laboratories and LGSO:Ce. The LSO samples show excellent scintillation properties: high light output, close to 30,000 ph/MeV and good energy resolution of 7.3% FWHM for 137 Cs γ-source full energy peak. Time resolution measured in geometry fulfilling the PET scanners requirements is equal to 450 ps. We also present results from the measurements with LGSO:Ce by Hitachi Chemical Co., which is of similar chemical composition to LSO. LGSO, at present stage of development, shows about 20% lower light output than LSO and energy resolution of 12.4% FWHM for 662 keV γ-rays. LSO crystals used in our studies posses similar in scintillation properties, although we suppose that the details of the productions method are different due to the differences in Ce concentration. LGSO is a new and very promising scintillator due to lower background radiation in comparison to LSO, but it features worse energy resolution and smaller number of photoelectrons.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2007
LSO:Ce, LYSO:Ce and GSO:Ce single-crystal scintillator light emission characteristics were studied in the low γ-ray energy range (99mTc source) used in nuclear medical imaging. The absolute luminescence efficiency and the optical emission spectrum of the three scintillators were measured, under γ-ray excitation using an integration sphere coupled to a photomultiplier and an optical spectrometer, respectively. Spectral compatibility of all scintillators to optical sensors was also estimated. The absolute luminescence efficiency of all crystals was found adequately high (8.7 μW m−2/μGy s−1 for GSO:Ce, 15.3 μW m−2/μGy s−1 for LYSO:Ce and 20.0 μW m−2/μGy s−1 for LSO:Ce). Their emission spectra were found compatible (57–94%) to currently employed optical photon detectors.
IEEE Transactions on Nuclear Science, 2000
Cerium-doped lutetium oxyorthosilicate (LSO) is amongst the most promising new scintillators discovered in almost five decades, with a unique combination of important properties for x and gamma-ray spectroscopy, namely: high density, fast decay, and large light yield. LSO seems to be a prime candidate to replace BGO in PET systems. However, the practical utilization of LSO is hindered by difficulties related to crystal growth (Czochralski method) due to the high temperatures employed. A new approach has been developed using a low-temperature crystal growth technology to produce scintillating LSO crystals. Light transparent polycrystalline LSO samples of a few mm3 in volume were grown and characterized by XRD, optical absorption, light decay measurement and gamma-ray spectral response. The properties of the new crystals compared well with highquality crystals grown by the Czochralski method.
Fusion Engineering and Design, 2018
Neutron and gamma detectors will play an essential role during operation of ITER and future fusion reactors. They are required in systems to monitor the total neutron production from the plasma for control and safety. Neutron and gamma detectors being considered employ scintillators that will be exposed to high neutron and gamma radiation levels. In this work a systematic study of the effect of gamma radiation on different types of scintillators (plastics, liquids and single crystal), candidates for detectors in future machines, has been done. The experiments were performed at the CIEMAT Nayade 60 Co gamma irradiation facility, measuring in-situ radiation induced optical absorption (RIA) and radioluminescence (RIL) from 370 to 730 nm. The RIA and RIL at 0.2 Gy/s up to 40 kGy and at 1.2 Gy/s to 240 kGy show reduced efficiency with dose, i.e. increased absorption and reduced luminescence. Rapid degradation for the single crystal Stilbene, with a drastic light emission drop by 20 kGy due to self-absorption, has been observed. Of the solid plastic scintillators, BC-418 exhibits the best behaviour. Liquid scintillators for a high radiation environment show negligible radiation induced absorption and emission loss. Details of the RIA and RIL degradation with dose for the different scintillators are presented.
Radiation Resistance of Composite Scintillators Based on Grains of Oxide Single Crystals
Acta Physica Polonica A, 2022
A large number of experiments carried out at charged particle accelerators indicate that the radiation dose accumulated by the scintillation materials contained in detectors is significant. For example, in experiments at the Large Hadron Collider, the radiation dose in scintillation detectors can reach 10 Mrad and will increase in the future. In this connection, the search for new radiation-resistant scintillation materials is especially important. Irradiation can significantly alter the characteristics of the scintillator material. The aim of this work was to study the features of possible radiation damage and transformations in composite scintillators under the action of ionizing radiation. We focused on composite scintillators, which are transparent non-luminescent gel-compositions containing grains of scintillation oxide single crystals. A comparative analysis of the spectra of the relative light yield, transmission, and luminescence, as well as their dependence on the accumulated dose for various composite scintillators, has been carried out. Possible mechanisms of radiation changes occurring in scintillators under irradiation are proposed and the influence of these processes on the radiation resistant of composite scintillators is analyzed. In this work, as in previous works in this series, we irradiated composite scintillators on a linear electron accelerator. The electron energy was 10 MeV. We irradiated with a low (0.2 Mrad/h) and a high (1500 Mrad/h) dose rate. At low dose rate, cracking occurs at lower radiation dose values (about 100-200 Mrad) than under irradiation at a high dose rate (up to 500 Mrad). The luminescent characteristics of the scintillator changed insignificantly until the gel composition fixing single-crystal grains cracked. After destruction of the gel composition, an abrupt deterioration in the properties of the sample took place.