Preparation and Properties of Scintillating Glasses in the SiO_2-Li_2O-CaO-Gd_2O_3 System

A series of scintillating glass in SiO2-Li2O-CaO, SiO2-Li2O-CaO-Gd2O3 were developed to explore the influence of different composition on the density and the luminescent properties of the sample. The effects of Ce^3＋ sources and melting atmosphere on the light yield of the scintillating glass were investigated. Results show that the highest density of the scintillating glass in this study is as high as 3.3 g/cm^3 and the highest light yield have reached 1175 phonons/Mev, which is about 3% of the light output of NaI：Ti. The introduction of Gd2O3 in the system could increase the glass density visibly and do not lower the light yield of the scintillating glass. The glass-melting atmosphere has strong influence on the light yield of Ce^3＋-doped scintillating glasses and strong reducing atmosphere results in high light yield. The light yield of scintillating glass with Ce^3＋ from CeF3 is much higher than that of corresponding glass with Ce^3＋ from Ce2O3.

Effects of substitution of BaF_2 for GdF_3 on optical properties of dense oxyfluoride borogermanate scintillating glasses

Eu3＋-activated B2O3-GeO2-37Gd2O3-3Eu2O3-（15-x）GdF3-xBaF2 （0≤x≤15） scintillating glasses with the density of 6.1-6.3 g/cm3 were synthesized by a melt-quenching method. The substitution of BaF2 for expensive GdF3 in oxyfluoride borogermanate glasses slightly decreased the glass density within 3.0%. Their optical properties were characterized by transmittance, photolumines- cence （excitation and emission）, and X-ray excited luminescence （XEL） spectra in detail. The emission intensity of Eu3＋ ions increased with the elevated x values. The Eu-O covalancey nature and the local environment of Eu3＋ ions were evaluated by Judd-Ofelt results. It was found that the covalency property of Eu-O bond increased with increasing x values.

Luminescent properties of Tb3＋ doped high density borogermanate scintillating glasses

Tb3＋-doped high density borogermanate glasses were prepared by melt-quenching method. Their physical and luminescent properties including differential thermal analysis（DTA）, density, transmittance spectra, photoluminescence, and X-ray excited luminescence spectra were investigated. The densities of the glasses doped with Tb3＋ were in the range from 5.690 to 6.086 g/cm3. Under UV and X-ray excitations, the glasses showed intense green emissions. The lifetimes of Tb3＋ doped borogermanate glasses were in the range from 1.597 to 1.869 ms. The results indicated that Tb3＋ doped borogermanate glasses could be scintillator candidate used in X-ray detection application.

Luminescence Characteristics of Ce^(3+) Doped Ca-Al-Ba Glass

The Al-Ca-Ba glass system with good chemical durability was firstly investigated as the scintillators host. Luminescence properties of Ce3＋ ions in this glass were studied, and obvious red shift and larger stokes shift with respect to others system were investigared. The excellent physical property such as high density and large refractive index implies this glass as an important material for the high quality scintillating fiber.

Optical and luminescence characteristics of Eu^(3+)-doped B_2O_3:SiO_2:Y_2O_3:CaO glasses for visible red laser and scintillation material applications

Europium（Eu^3＋） doped glasses of chemical compositions（55-x）B2O3：10 SiO2：25 Y2O3：10CaO：xEu2O3,where x denotes mol% and ranges 0≤ x ≤ 2.5, were synthesized by adopting conventional melt quenching technique, Physical properties like density, molar volume, polaron radius, inter-ionic distance and field strength of the glass samples were investigated to assess the impact of Eu2O3. Optical and luminescence properties of the glasses were characterized with optical absorption, photoluminescence,X-ray induced emission spectra, temperature dependence emission spectra and decay times. Judd-Ofelt（JO） intensity parameters（Ωλ） of the glasses were evaluated based on the absorption spectrum of 0.5 mol%. JO parameters, calculated from absorption spectra with thermal corrections on oscillator strength, were used to evaluate radiative properties such as radiative transition probability（AR）,branching ratio（βR）, stimulated cross section emission（σ） and radiative lifetime（τR） for 5D0→7 FJ（J = 0,1,2,3 and 4） transitions. The decay rate of 5D0 fluorescent level for all the glass samples was single exponential. Lifetimes of the 5D0 level were decreased with increasing concentrations of Eu^3＋ions from 0.05 mol% to 2.5 mol% which might be due to energy transfer through cross-relaxation in the glasses. The chromaticity coordinates（x, y） were similar for all BSYCaEu glasses and were located at the red region of CIE 1931 color chromaticity diagram. Hence, these results confirm that the Eu^3＋ doped BSYCaEu glasses could be useful for visible red lasers and glass scintillation applications.

Comparison of thermal neutron detection ef f iciency of 6Li scintillation glass and 3He gas proportional tube

We report on a comparison study of the 3He gas proportional tube and the 6Li incorporated scintillation glasses on thermal neutron detection efficiency. Both 3He and 6Li are used commonly for thermal neutron detection because of their high neutron capture absorption coefficient. By using a neutron source 252Cf and a paraffin moderator in an alignment system, we can get a small beam of thermal neutrons. A flash ADC is used to measure the thermal neutron spectrum of each detector, and the detected number of events is determined from the spectrum, then we can calculate the detection efficiency of different detectors. Meanwhile, the experiment has been modeled with GEANT4 to validate the results against the Monte Carlo simulation.