Irradiation effect on natural quartz from Zambia

AbstractThe effects of high gamma-irradiation doses (50-300 kGy) on natural quartz crystals have been investigated by ESR technique. The ESR spectrum carried out at low temperature (120K) displayed lines group of Al center. The higher amount of gamma doses affected ESR spectra by increasing of intensity, especially the increasing intensity in the range of the Al center. The complex ESR spectra of Al center observed to contain 9 peaks that did not reach saturation even though the level of gamma-irradiation dose was as high as 300 kGy. The total area under ESR spectra of Al center was increased as a polynomial function of irradiated dose. The overlapping of ESR signal from defects in the range of Al center was also investigated

The influence of CeF₃ on radiation hardness and luminescence properties of Gd₂O₃–B₂O₃ glass scintillator

The effect of CeF3 concentration and γ-irradiation on the physical, optical and luminescence properties of Gd2O3–B2O3–CeF3 glasses were studied in this work. Before irradiation, the addition of CeF3 in glass degraded the network connectivity observed from FTIR and possibly created the non-bridging oxygen (NBO) in glass structure. This NBO caused the reduction of Ce3+/Ce4+ ratio in XANES, the red-shift in transmission spectra and the raise of refractive index with addition of CeF3 content. Such red-shift also was influenced by 4f–5d transition of Ce3+ dopant. This ion generated the strongest photoluminescence (PL) and radioluminescence (RL) in 0.3 mol% CeF3-doped glass with nanoseconds decay time. The irradiation with γ-rays damaged the glass structure, broke the chemical bonds, and created color center in the glass network. The non-bridging oxygen hole center (NBOHC), that absorbed photons in the visible light region, caused the darkening, color change and increment of refractive index. These irradiation effects on glass were mitigated by the addition of CeF3 that the electron donation of Ce3+ decreased the number of NBOHC. The Ce3+/Ce4+ ratio in most glasses after irradiation then reduced compared to them before irradiation, resulting to the decrease in PL and RL intensity. Our results confirm that CeF3 can enhance the radiation hardness of glass and the 0.3 mol% CeF3-doped glass is a promising glass scintillator.Kaewnuam E., Wantana N., Ruangtaweep Y., et al. The influence of CeF₃ on radiation hardness and luminescence properties of Gd₂O₃–B₂O₃ glass scintillator. Scientific Reports 12, 11059 (2022); https://doi.org/10.1038/s41598-022-14833-3

First Results from the AMoRE-Pilot neutrinoless double beta decay experiment

The Advanced Molybdenum-based Rare process Experiment (AMoRE) aims to search for neutrinoless double beta decay (0$\nu\beta\beta$) of $^{100}$Mo with $\sim$100 kg of $^{100}$Mo-enriched molybdenum embedded in cryogenic detectors with a dual heat and light readout. At the current, pilot stage of the AMoRE project we employ six calcium molybdate crystals with a total mass of 1.9 kg, produced from $^{48}$Ca-depleted calcium and $^{100}$Mo-enriched molybdenum ($^{48\textrm{depl}}$Ca$^{100}$MoO$_4$). The simultaneous detection of heat(phonon) and scintillation (photon) signals is realized with high resolution metallic magnetic calorimeter sensors that operate at milli-Kelvin temperatures. This stage of the project is carried out in the Yangyang underground laboratory at a depth of 700 m. We report first results from the AMoRE-Pilot $0\nu\beta\beta$ search with a 111 kg$\cdot$d live exposure of $^{48\textrm{depl}}$Ca$^{100}$MoO$_4$ crystals. No evidence for $0\nu\beta\beta$ decay of $^{100}$Mo is found, and a upper limit is set for the half-life of 0$\nu\beta\beta$ of $^{100}$Mo of $T^{0\nu}_{1/2} > 9.5\times10^{22}$ y at 90% C.L.. This limit corresponds to an effective Majorana neutrino mass limit in the range $\langle m_{\beta\beta}\rangle\le(1.2-2.1)$ eV

Tri-doped Ln3+ ions in barium zinc borate glasses: Luminescence behavior at room and cryogenic temperatures

The research work carried out in the paper reports on the effect of BaO and tri doped Er3+, Tb3+, and Gd3+ ions on luminescence characteristics in zinc borate glasses. The work emphasizes the effect of BaO on tri-doped lanthanide ions in borate glasses. The addition of 5 mol% BaO content in the glasses shows more non-bridging oxygens and decreases with addition of BaO content (10 mol%). Glasses show emissions at 311 nm, 543 nm, and 1540 nm for Gd3+, Tb3+, and Er3+ ions, respectively. The Judd-Ofelt method was applied to bring out the significance of the oscillator strength of Tb3+ ions. Higher value of Ω2 was observed in the present glasses indicating their rare-earth covalency is more around Tb3+ ions. Low-temperature luminescence studies were studied for the T2 glass sample for Tb3+ ions. Cryogenic temperature luminescence studies were studied to bring out the significance of 5D4 to 7FJ (J = 3, 2, 1, 0) which is not normally visible at room temperature. The energy is transferred from the Gd3+ to the Tb3+ ions by the Gd3+ ions acting as sensitizers, which helps to adjust the excitation wavelength. Yellowish-green-emitting glasses were observed by illuminating UV light and verified as such from the CIE diagram. The prepared glasses are potential candidate for visible-emitting around yellowish-green colour emitting capability and NIR emitting optical devices and broadband amplifier applications

CuO, MnO2 and Fe2O3 doped biomass ash as silica source for glass production in Thailand

In this research, glass productions from rice husk ash (RHA) and the effect of BaO, CuO, MnO2 and Fe2O3 on physical and optical properties were investigated. All properties were compared with glass made from SiO2 using same preparations. The results show that a higher density and refractive index of BaO, CuO, MnO2 and Fe2O3 doped in RHA glasses were obtained, compared with SiO2 glasses. The optical spectra show no significant difference between both glasses. The color of CuO glasses show blue from the absorption band near 800 nm (2B1g → 2B2g) due to Cu2+ ion in octahedral coordination with a strong tetragonal distortion. The color of MnO2 glasses shows brown from broad band absorption at around 500 nm. This absorption band is assigned to a single allowed 5Eg → 5T2g transition which arises from the Mn3+ ions (3d4 configuration) in octahedral symmetry. The yellow color derives from F2O3 glass due to the homogeneous distribution of Fe3+ (460 nm) and Fe2+ (1050 nm) ions in the glass matrices. Glass production from RHA is possible and is a new option for recycling waste from biomass power plant systems and air pollution reduction. Keywords: Rice husk ash, Glass, Optical, Physica