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Rare-earth (RE=Sm, Pr, Tb, Tm) doped ternary sulfides having the general formula KLn 0.995RE0.005 S 2 (Ln=La, Gd, Lu) and undoped KLnS 2 were synthesized in the form of crystalline hexagonal platelets by a chemical reaction in an electric resistance furnace under the flow of hydrogen sulfide. X-ray powder diffraction confirmed only a single phase of the rhombohedral lattice system (space group R-3 m). Time-resolved luminescence spectroscopy was employed to investigate radioluminescence, photoluminescence, decay kinetics and absorption spectra. The KLnS 2 band edge at 300–330 nm was found and characteristic Pr^3+, Sm^3+, Tb^3+ and Tm^3+~ 4 f -4 f emission lines in the visible spectral range were observed. The charge transfer transitions in the Pr^3+- and Sm^3+-related excitation spectra in the range 330–370 nm are described and the eficient energy transfer from the host to the emission centers is revealed. We discuss the potential for application of these materials in white LED solid-state lighting and X-ray phosphors. [ABSTRACT FROM PUBLISHER]

Non-stoichiometric undoped zirconates of Ca, Sr and Ba were prepared and studied for their luminescence and scintillation characteristics in a broad range of compositions. Powder samples were prepared by solid state reaction method. Based on phase analysis the zirconate phases compositions in the sintered samples have been determined. Dominant emission band of these materials is situated in near UV-blue spectral range. The highest scintillation efficiency was found at the samples of the strontium zirconate containing surplus of ZrO2. [ABSTRACT FROM PUBLISHER]

The ^3He shortage is forcing the neutron community to look for other detection methods. The inorganic scintillator may be an alternative. Thermal-neutron detection by means of inorganic scintillators has successfully been realized on a large scale at ISIS, UK, using ^6LiF/ZnS:Ag mixed with an organic binder. This material is now introduced in the security field. For several reasons other traditional neutron scintillators, ^6Li-glass:Ce and ^6LiI:Eu, and relatively new materials such as ^6Li6Gd(BO3)3:Ce and elpasolites like Cs2LiYCl6:Ce and Cs2LiLaBr6:Ce are hardly used or did not yet find their way to application. The same applies to more recently studied materials of the LICAF group. The pros and cons of these inorganic materials for thermal neutron detection will be discussed. [ABSTRACT FROM PUBLISHER]

Experiments to search for neutrinoless double beta decay are considered as an unique tool to study properties of neutrino and weak interactions. Scintillation detectors possess important properties required for high-sensitivity double beta decay experiments: presence of elements of interest, low level of intrinsic radioactivity, reasonable spectrometric characteristics, fast response, pulse-shape discrimination ability. Moreover, some crystal scintillators can be applied as cryogenic scintillating bolometers with high energy resolution and excellent particle discrimination. High concentration of isotope of interest and as low as possible radioactive contamination are important requirements to a scintillation material to be used in double beta decay experiments. Therefore development of radiopure crystal scintillators from isotopically enriched materials is required. Other important issues are maximal output of detectors and minimal loss of enriched materials. High quality, radiopure cadmium tungstate crystal scintillators were developed from enriched ^106Cd and ^116Cd, while calcium molybdate scintillators were grown form calcium depleted in ^48Ca and molybdenum enriched in ^100Mo. Prospects of several scintillation materials, promising for double beta experiments, are discussed. [ABSTRACT FROM PUBLISHER]

The influence of the geometry of the scintillators is presented in this paper. We focus on the effect of narrowing down the section of crystals that have a given length. The light output of a set of crystals with very similar scintillating properties but different geometries measured with several coupling/wrapping configurations is provided. We observe that crystals shaped in thin rods have a lower light output as compared to bulk or sliced crystals. The effect of unpolishing the crystal faces is also investigated, and it is shown that highest light outputs are not necessarily obtained with crystals having all faces polished. Simulation results based on a realistic model of the crystal that implements light scattering on the crystal edges are in agreement with the experimental data. Fine-tuning of this model would allow us to further explore the details of light propagation in scintillators and would be highly valuable to fast timing detection and highly granular detectors. [ABSTRACT FROM PUBLISHER]

Excellent properties of optical ceramics initially developed as laser materials make them attractive for scintillator applications. The effects of the porosity of ceramics on their luminescence properties is analyzed using a simplified model to account for scattering. The results of the study of optical and luminescence properties of a concentration series of YAG:Yb ceramics fabricated by vacuum sintering and nanocrystalline technology (VSN method) in a wide UV and VUV and X-rays excitation energy range are presented. The results are compared to those obtained for Yb-doped single crystals and undoped YAG ceramics and single crystals. [ABSTRACT FROM AUTHOR]

Technology of producing single crystal scintillators is rather a hard and complex technological task connected with a very low output issue (15-50%) of the material and the restricted area of its application. Recent efforts of scientists are directed toward searching for alternative ways for producing these materials. It was established that high-performance ceramic scintillation materials for producing the scintillators could be prepared by using powder metallurgy techniques. However despite of certain achievements in this area, transparency of ceramic scintillators is still under the question. In our opinion a key to the solution of the problem lies in preparing scintillators in nanocrystalline structural state. A technology developed on the basis of the modified Sol-Gel method shows possibilities of manufacturing number of standard (as well as new hard to obtain as single crystals) scintillation materials. Present work is dedicated to the problems of manufacturing yttrium orthosilicate (Y2SiO5 )—as of one of the perspective scintillation materials. [ABSTRACT FROM AUTHOR]

Our experiments with nanocrystalline scintillating rare earth oxides and rare earth fluorides have shown that in some cases nanoscopic dimensions provide essential improvement of the most important scintillation parameters: light yield, kinetics of scintillations, radiation hardness, etc. We found that in the range from 20 to 100-nm of the oxide and fluoride particles there are 3 types of layered structures: with expanded exterior layer, with changed phase structure, and with changed chemical composition. These layered structures can strongly influence scintillation parameters: cause an increase or decrease in the light yield, vary scintillation kinetics, modify radiation hardness, etc. Control of dimensions and structures of nanoscintillators can be used for significant modifications of parameters of radiation detectors (radical acceleration of kinetics, enhancement of light yield, increase in radiation hardness, etc.). Radiation detectors based on nanoscintillators have promising prospects for applications in new generations of devices for medical diagnostics, security inspection, radiation monitoring of nuclear reactors. [ABSTRACT FROM AUTHOR]

Atomic-scale simulations have been employed to predict the site solution preference of Bi3+ activator cations in a series of RE2 O3 scintillators with the bixbyite crystal structure (Ia3), where RE denotes a 3+ cation ranging in size from Sc3+ to La3+. There are two crystallographically unique cation sites in the bixbyite structure, in Wyckoff notation referred to as the 24d and 8b site. It is expected that the spectroscopic properties of an activator cation residing on the 24d site will be different from the same activator cation residing on the 8b site, due to the distinct symmetries (C2 and S6 respectively) of these two sites. Previous studies have revealed two different Bi3+ emissions in Y2O3 corresponding to Bi3+ cations occupying both lattice 24d and 8b sites. By predicting the energy difference of the Bi3+ solution on the 24d and 8b sites, we are able to predict the distribution of Bi3+ in a range of bixbyite compounds. [ABSTRACT FROM AUTHOR]

CeBr3 crystals have been studied to assess their utility as potential gamma ray spectrometers for future ESA planetary missions. Pulse height spectra, scintillation time profiles, X-ray excited emission spectra, and photoluminescence spectra have been recorded as a function of temperature between 78 and 600 K. In addition, the influence of exposing CeBr3 to various doses of gamma rays from a strong 60Co source on its scintillation performance has been investigated. [ABSTRACT FROM AUTHOR]

The focus of this paper is the evaluation of the new fast 51 mm-diameter, 8-stage Hamamatsu R9779 photomultipliers (PMTs) with an acceleration-ring at the front-end and the Photonis XP20D0 PMTs with a screening grid in front of the anode. The following performance characteristics are presented: Timing resolution, anode-scan-uniformity and transit-time spread. The unfolded timing resolution for two R9779 was 192 ps and 210 Ps using plastic scintillators. The individual timing resolutions for two XP20D0 using plastic scintillators are 181 ps and 154 ps, respectively. The variation in time resolution across the windows of the two R9779 ranged between 117 ps and 171 ps, and 79 ps and 73 ps for the two XP20D0 PMTs. [ABSTRACT FROM AUTHOR]

The temperature dependence (from -20 to +20 degrees C) of gamma-ray irradiated light outputs, energy resolutions, and decay time profiles of three YAG:Ce poly-ceramic scintillators are studied. The Ce concentrations are 0.5, 0.05, and 0.005 mol%. The relative light yield of the YAG:Ce with 0.5 mol% with a 2 μs shaping time was measured as 1 : 1.08 : 1.14 at +20, 0, and -20 degrees C, respectively, including the temperature dependence of the phototube (-0.2 %/degree). The energy resolution stays almost constant at 7.2% for 662 keV gamma-rays. The ceramic with 0.05 mol % shows the almost same properties, while the light yield of that with 0.005 mol% is 2–4 times lower (hence the energy resolution becomes 14–19%). All the scintillators exhibit good linearities within ∼ 1% between the light output and the irradiated gamma-ray energy from 59.5 keV to 662 keV. The decay time constants of the dominant decay components are about 80 ns and 300 ns at +20 degrees C. As the temperature increases from -20 to +20 degrees C, the effective decay of all the ceramics becomes faster, because the decay time constants and fractions of the slower components shorten and decrease, respectively. This result suggests that carriers which are captured in shallow traps before transferring excitation to Ce ions can escape the traps more easily at higher temperatures. Considering the decrease of the total light yield toward higher temperatures, it is thought that thermal quenching starts to dominate the temperature dependence of the ceramic YAG:Ce around the room temperature. The 0.5 mol% scintillator shows a lower quenching energy than the 0.05 mol% one. This can be explained in terms of self absorption of Ce emission. [ABSTRACT FROM AUTHOR]

Pulse height spectra of various sources covering X-ray and gamma ray energies from 10 keV to 6.1 MeV were measured by the first large Ø19 × 19 mm3 LaBr3 : 0.5% Ce3+ scintillator. The spectra are compared with that recorded with a same sized NaI:T1+ scintillator. Excellent energy resolution pulse height spectra are obtained showing that the scaling up from a small (≈ 3 x 3 x 10 mm3) sized LaBr3 : Ce3+ scintillator studied initially up to an ≈ 6 cm3 scintillator does not lead to much deterioration of resolution and light output. Special attention is devoted to the nonproportionality in the response of LaBr3 : Ce3+ and related energy resolution. At high energy LaBr3 : Ce3+ is far superior above NaI:T1+ in terms of energy resolution and scintillation speed. At energies below 100 keV, NaI:T1t shows a better energy resolution. [ABSTRACT FROM AUTHOR]

Investigates the pulses from LSO and LuYAP crystals in order to find a practical method of distinguishing. Difference in the fast decay components of LSO and LuYAP; Evaluation of pulse shape in time domain; Simplification of layer identification in a phoswich detector of two different short decay time scintillators.

Describes a scintillator based on a transparent ceramic of Lu[sub2]O[sub3]:Eu. Imaging performance of the pixelated scintillator; Advantages offered by transparent optical ceramics (TOC) for scintillator applications over powder screens; Overview of TOC preparation and properties.

The SCINT series of conferences on Inorganic Scintillators and their Applications has provided, beginning in 1992, a regular platform for researchers from all over the world working in this field. This conference merges the aspects of basic science with application-related issues in the field of inorganic scintillators and phosphors and provides unique opportunities for both scientists and engineers to exchange their new results and ideas. Previous SCINT conferences were held first in Chamonix in 1992 and then in San Francisco, Delft, Shanghai, Moscow, Chamonix, Valencia, Alushta, Winston- Salem, and Jeju Island in Korea in 2009. The most recent, the 11th International Conference on Inorganic Scintillators and their Applications (SCINT 2011), was held at the Science Campus of Justus Liebig University, Giessen, Germany, September 11?16, 2011. There were a total 187 scientific contributions, 82 oral presentations, 19 invited talks, and 105 poster exhibitions presented by 235 participants from 24 different countries. For the first time, a pre-conference tutorial was organized, which covered the basic physics of scintillation mechanisms as well as the wide field of applications. The purpose was mainly to educate students and newcomers in the field. This special issue of the IEEE TRANSACTIONS ON NUCLEAR SCIENCE comprises the refereed proceedings of SCINT 2011, containing 61 papers on the research presentations. [ABSTRACT FROM PUBLISHER]