Single crystals of PbWO
4 and Lu
3Al
5O
12-based scintillators were studied by correlated electron paramagnetic resonance and thermally stimulated luminescence experiments. The nature of some of the ...intrinsic trapping centers and their role in the energy transfer and storage processes were explained. Examples of material doping and co-doping are given, which succeeded in suppression of specific point defects and improvement of scintillation performance.
New crystals for dual-readout calorimetry Akchurin, N.; Bedeschi, F.; Cardini, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2009, Letnik:
604, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Lead tungstate crystals doped with small fractions of praesodynium or molybdenum have been tested in beams of high-energy electrons. The goal of these tests was to study the effects of such dopants ...on the capability to separate the signal components deriving from the Cherenkov and scintillation light generated by the beam particles. These studies were carried out in view of the possible application of such crystals in dual-readout calorimeters.
Fourier transform absorption spectroscopy in the 500a6000cma1 and 9a300K ranges is applied to monitor the effects produced by Eu3+ incorporation into sol-gel silica samples doped with concentration ...increasing from 0.001 to 10mol%. The aim is to investigate the formation of aggregates by exploiting the Eu3+ crystal-field transitions. Complementary microreflectance and Raman spectra are also measured in the range of silica intrinsic vibrational modes to confirm the hypothesis of matrix modification induced by increasing doping levels. Evidences of clustering are found for high Eu3+ concentrations. Up to 3mol% the crystal-field line intensities gradually increase and the OHa content smoothly decreases. A further increase to 10mol% causes drastic, remarkable changes, i.e. sharp crystal-field lines appear which narrow by lowering the temperature. Furthermore, the OHa related bands are no longer detectable. For concentrations up to 3mol% the aggregates are amorphous as the silica matrix, while for the Eu3+ 10mol% sample they show a rather ordered structure.
Optimization of crystals for applications in dual-readout calorimetry Akchurin, N.; Bedeschi, F.; Cardini, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2010, Letnik:
621, Številka:
1
Journal Article
Recenzirano
We present a systematic study of lead tungstate crystals doped with a small fraction of molybdenum, varying between 0.1% and 5%. These crystals were exposed to a beam of 50
GeV electrons and the ...signals were unraveled into scintillation and Cherenkov contributions, using the time structure of the signals and/or different types of transmission filters. These studies were carried out in view of the possible application of such crystals in dual-readout calorimeters.
We improve a recently proposed approach for the evaluation of the thermal ionization barrier of the lanthanide excited states in luminescent materials by taking into account the effect of traps and ...their decay time temperature dependence. We present two distinct methods, and we apply them to the case of Lu sub(2)Si sub(2)O sub(7):Pr. To this purpose, wavelength resolved thermally stimulated luminescence and photoluminescence time decay measurements extending up to the ms time scale have been performed. In the frame of the first method, the thermal ionization barrier of the Pr super(3+) 5d sub(1) excited state has been evaluated by studying the progressive filling of traps during illumination by ultraviolet light within the 4functionof-5d sub(1) absorption band of Pr super(3+) at different temperatures. The thermal ionization barrier turned out to be 0.54 + or - 0.05 eV. In the second approach this parameter has been calculated by a numerical reconstruction of the temperature dependence of the 5d sub(1) -4functionof delayed recombination decay integral in two different time windows (53.3 mu s - 10.3 ms and 53.3 mu s - 600 s) with the sum of contributions from different traps whose parameters have been investigated by thermally stimulated luminescence (TSL). The results obtained are in agreement with those found using the trap-filling method. The advantages and limits of both approaches have been critically exposed, in order to discuss the possibility of their extensive employment for the determination of the ionization barrier of a rare earth ion excited-state level in an insulating host.
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