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The AMoRE-II experiment will search for the 0νββ decay of 100Mo nuclei using molybdate crystal scintillators, operating at milli-Kelvin (mK) temperatures, with a total of 80 kg of 100Mo. The background goal for the experiment is 10–4 counts/keV/kg/year in the region of interest around the 0νββ decay Q-value of 3,034 keV. To achieve this level, the rate of background signals arising from emissions produced by decays of radioactive impurities in the detector and shielding materials must be strictly controlled. To do this, concentrations of such impurities are measured and are controlled through materials selection and purification. In this paper, we describe the design and the construction materials used to build the AMoRE-II detector and shielding system, including active and passive shielding, the cryostat, and the detector holders and instrumentation, and we report on measurements of radioactive impurities within candidate and selected materials.

The motivation for this research is that the emission spectra using directly pumped laser diodes have not yet been found. We want to explore the luminescence properties of a co-doped laser material utilizing a diode laser as an optical pump. The research method used standard melt-quench and was stimulated by a laser diode (808 and 980 nm). The double doped of Nd3+- Er3+/Nd3+-Pr3+ ions with glasses system of lithium-fluorophosphate (LFP) had a strong band emission at 1056 nm, which transitioned at 4F3/2 → 4I11/2 and showed a drop in intensity from co-doping with Er3+ and Pr3+ ions. The fluorescence width at half maximum (FWHM) of the glasses is calculated to identify whether the sample may be used as a laser application. The FWHM values are found to be 22–28 nm. Decay time values were shown to decrease with increasing concentrations of Er3+ and Pr3+ ions and were used for energy transfer calculations. The Quantum Yields (QYs), efficiency in the transfer of energy and the possibility transfer energy were measured and calculated that confirm the possibility of energy transfer from Nd3+ to Er3+ and Pr3+ ions. Since, the emission spectrum at 1535 nm was found, this is a good reason for it to be used as an optical device.

In the current study, the bismuth oxide (Bi2O3) content was inter-substituted with gadolinium oxide (Gd2O3) in sodium borate glass. Glass sample density and molar volume values show a reverse trend. The optical transparent radiation shielding glasses are more commonly used materials in hospitals or any hazardous radiation working environments, the glasses used in this work are more emphasized on their superior transmittance and acceptable for shielding materials for commercial purposes. The optical band gap value was calculated using the Tauc plot and absorption fitting method. Radiation shielding parameters like mass attenuation co-efficient, effective atomic number, effective electron density, equivalent atomic number, lead equivalent thickness, half value layer, tenth value layer, Geometric-Progression fitting parameters like (b, c, a, XK, and d), γ-ray build-up factor, and exposure build-up factor have all been evaluated. In the current work, photoluminescence studies for Gd3+ ions were investigated and discussed.

Abstract The Advanced Mo-based Rare process Experiment (AMoRE)-Pilot experiment is an initial phase of the AMoRE search for neutrinoless double beta decay of $$^{100}$$ 100 Mo, with the purpose of investigating the level and sources of backgrounds. Searches for neutrinoless double beta decay generally require ultimately low backgrounds. Surface $$\alpha $$ α decays on the crystals themselves or nearby materials can deposit a continuum of energies that can be as high as the Q-value of the decay itself and may fall in the region of interest (ROI). To understand these background events, we studied backgrounds from radioactive contaminations internal to and on the surface of the crystals or nearby materials with Geant4-based Monte Carlo simulations. In this study, we report on the measured $$\alpha $$ α energy spectra fitted with the corresponding simulated spectra for six crystal detectors, where sources of background contributions could be identified through high energy $$\alpha $$ α peaks and continuum parts in the energy spectrum for both internal and surface contaminations. We determine the low-energy contributions from internal and surface $$\alpha $$ α contaminations by extrapolating from the $$\alpha $$ α background fitting model.

Barium metaphosphate glasses (PBaLa) doped with erbium (Er3+) ions have been prepared by melt quenching method and studied their optical, structural characteristics by using FT-IR, absorption, radiative de-excitation spectra, decay curves and up-conversion measurements. Judd-Ofelt (Ωλ, λ = 2,4 and 6) parameters have been determined using the absorption transitions of the Er3+(1.0 mol %)-doped glasses which are in turn taken to predict the radiative characteristics that include branching ratio (βR), radiative emission probability (AR) and lifetime (τR) of some important fluorescent levels of Er3+:glasses. Visible emission spectra measured under 378 nm excitation reveals three emission transitions at 663 (4F9/2 → 4I15/2), 547 (4S3/2→ 4I15/2) and 524 nm (2H11/2 → 4I15/2) corresponding to Er3+ ions. Among these, the green emission at 547 nm is relatively intense. Near-Infrared emissions were measured by exciting at 980 nm which exhibits broad emission at 4I13/2→ 4I15/2 (1.53 µm). The stimulated emission cross-section (σemi), FWHM and gain bandwidth (σemi × FWHM) were predicted to be 13.58 × 10-21 cm−2, 59 nm and 801.2 cm3, respectively, for PBaLaEr1.0 glass. The lifetime of 4I13/2 level has been shortened from 2.53 to 0.8 ms with an increase in Er3+ ions concentration from 0.1 to 2 mol %. NIR to visible up-conversion has also been measured for various concentrations of Er3+-doped PBaLaEr glasses with 980 nm excitation. These findings indicate that the Er3+-doped PBaLaEr glasses can be considered for waveguide laser and optical amplifier applications at 1.53 µm.

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.

Abstract 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.

The impact of varying Sm2O3 content on radiation shielding properties of 15PbF2: (65-x) B2O3: 20K2O:xSm2O3 (where 0 ≤ x ≤ 1.5 mol %) glass samples, was investigated by studying their physical, radio-luminescence and X-ray-shielding characteristics. The density of glasses increased with an increase in Sm2O3 contents. Evaluating the X-ray shielding parameters like mass and linear attenuation coefficients, half- and tenth- value layer, lead equivalent thickness and mean free path, it was found that the linear and mass attenuation coefficients decrease with a rise in Sm3+ concentration in the 70–120-kVp-energy range. The half- and tenth-value layers of the developed glasses increase with increasing energy and vary randomly with changing Sm2O3 contents. Comparing the determined HVL data with that of the concrete, red brick, commercial window, and X-ray window at 120 keV, it is found that the developed glass performs better shielding. The obtained results revealed that this glass has excellent potential and could be used as a radiation-shielding material in various applications.

We report experimental investigations into the co-doping of Nd3+-Pr3+ ions in LFP glasses. The method used in this study is the melt quench technique. Several physical and structural properties were investigated in this work. The structural properties were investigated by FTIR (Fourier Transform infrared) and XANES (X-ray absorption near edge structure) spectroscopy. The location of the white line peak at ∼6210 eV and the intensity of L3-edge XANES of Nd depend on the ratio of O/Nd in the glass matrix. Several excitations exhibited the luminescence properties in the photo and near-infrared spectrophotometer. The excitation at 481 nm shows seven peaks in the Nd3+ and Pr3+ transitions in the visible region. Meanwhile, the near-infrared region shows three peaks of Nd3+ and Pr3+ transitions at ∼1.06 μm wavelength.

Abstract The advanced molybdenum-based rare process experiment (AMoRE) aims to search for neutrinoless double beta decay ($$0\nu \beta \beta $$ 0νββ ) of $$^{100}$$ 100 Mo with $$\sim 100\,\hbox {kg}$$ ∼100kg of $$^{100}$$ 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 $$^{48}$$ 48 Ca-depleted calcium and $$^{100}$$ 100 Mo-enriched molybdenum ($$^{48{{\text {depl}}}}\hbox {Ca}^{100}\hbox {MoO}_{4}$$ 48deplCa100MoO4 ). 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 $$0\nu \beta \beta $$ 0νββ search with a 111 kg day live exposure of $$^{48{{\text {depl}}}}\hbox {Ca}^{100}\hbox {MoO}_{4}$$ 48deplCa100MoO4 crystals. No evidence for $$0\nu \beta \beta $$ 0νββ decay of $$^{100}$$ 100 Mo is found, and a upper limit is set for the half-life of $$0\nu \beta \beta $$ 0νββ of $$^{100}$$ 100 Mo of $$T^{0\nu }_{1/2} > 9.5\times 10^{22}~\hbox {years}$$ T1/20ν>9.5×1022years at 90% C.L. This limit corresponds to an effective Majorana neutrino mass limit in the range $$\langle m_{\beta \beta }\rangle \le (1.2-2.1)\,\hbox {eV}$$ ⟨mββ⟩≤(1.2-2.1)eV .

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, Physical

Lithium yittrium/lanthanum borate glasses doped with Sm ion were prepared by melt quenching technique. Both glasses were studied comparatively in Sm ion local environment and its effect to luminescence properties. XANES indicated that Sm ions in both glasses act as Sm3+ similar as original in Sm2O3 powder. EXFAS result showed that Sm3+ in both glasses are surrounded with first shell neighbor by six particles of oxygen. Sm-O distance and its fluctuation value in LiYBSm is larger than in LiLaSm glass. Latter value represents more asymmetric environment around Sm3+ in LiYB than in LiLaB system. This lead to better ability of absorption and emission in LiYBSm glass which appear in the spectra. The first and second strongest emission of both glasses belong to photon with 600 and 646 nm, via 403 excitation wavelength. From J-O analysis, LiYBSm glass performs more potential than LiLaSm, for using as lasing medium in high power laser with 600 nm and low-energy consumption laser with 646 nm. Keywords: Glass, Samarium, EXAFS, Judd Ofelt

Radiative properties and spectroscopic studies of several Nd3+ doped Borate glass system have been reported. Judd-Ofelt intensity parameter and other parameters like oscillator strength (f), effective bandwidth (Dleff), radiative transition probabilities (AR), stimulated emission cross section (s), branching ratio (bR), radiative lifetime (tR) and experimental lifetime (texp) for the hypersensitive Nd3+ doped Borate Glass are listed and discussed. The variation of W2 values for the different host matrix are expressed their covalency among Nd3+ ions in the glass matrix. In this study, reported that the hypersensitive transition achieved at 4I9/2 ® 4G5/2, 2G7/2 centered at 580 – 585 nm range.

Physical, optical, and luminescence properties of Nd3+ ions in bismuth barium borate glass system were studied. The glasses prepared by a melt quenching method were doped at various Nd2O3 concentrations in compositions (40-x)B2O3 : 40Bi2O3 : 20BaO : xNd2O3 (where x = 0.00, 0.50, 1.00, 1.50, 2.00, and 2.50 in mol%). Luminescence properties of the glasses were studied under two excitations of 585 and 750 nm for downconversion. From both excitations, the results show emission bands in NIR region corresponding to the transitions between 4F3/2 → 4I9/2 (900 nm), 4F3/2 → 4I11/2 (1,060 nm), and 4F3/2 → 4I13/2 (1,345 nm). The luminescence intensity obtained with 585 nm excitation was stronger than 750 nm, with the strongest NIR emission at 1,060 nm. The upconversion emission spectrum exhibits strong fluorescence bands in the UV region at 394 nm (λex=591 nm). The processes are associated with excited state absorption (ESA) from 4F3/2 level to 4D3/2 level and it is the radiative decay from the 4D3/2 to ground levels (4D3/2 → 4I13/2) which are responsible for the emission at 394 nm.