Search

Ce3+‐doped 20Gd2O3–20Al2O3–60SiO2 (GAS:xCe3+) glasses (x = 0.3, 0.7, 1.1, 1.5, 1.9 mol%) with Si3N4 as a reducing agent were prepared. The density of the glasses is around 4.2 g/cm3. With the increase in the Ce3+ concentration, both the photoluminescence (PL) and PL excitation peaks of GAS:xCe3+ glasses show a redshift because the 4f–5d energy levels of Ce3+ ions are narrowed. PL quantum yield and PL decay time of GAS:xCe3+ glasses are 28.32–50.59% and 43–64 ns, respectively. In addition, they both first increases and then decreases with the Ce3+ concentration increasing, reached the maximum when x = 1.1 mol%. The integrated X‐ray excited luminescence (XEL) intensity of the GAS:1.1Ce3+ glass is 23.86% of that of Bi4Ge3O12 (BGO) crystal, and the light yield reaches 1200 ph/MeV with an energy resolution of 22.98% at 662 keV when exposed to γ‐rays. The PL and XEL thermal activation energies of GAS:xCe3+ glasses are independent of Ce3+ ions concentration. Scintillating decay time of the glasses exhibits two components consisting of nanosecond and microsecond levels, and the scintillating decay time gradually decreases with the Ce3+ concentration increasing. The difference between PL and scintillating decay time is discussed regarding the different luminescent mechanisms. [ABSTRACT FROM AUTHOR]

The upgrade of the BESIII end cap time-of-flight (TOF) detector needs to achieve a ~40-ps time resolution level to provide high-performance reference time for beam testing. Fast silicon photomultiplier tubes (SiPMs) have excellent time characteristics and the transition time spread (TTS) can reach tens of picoseconds. Therefore, SiPMs are selected to replace the PMTs in T0 detectors. In this article, we describe that the time characteristics of a fast SiPM and T0 system were studied using a high-speed real-time oscilloscope. In order to obtain the optimal time resolution, coupling techniques of the plastic scintillators and SiPMs were studied. Single-ended coupling between a SiPM and a plastic scintillator can obtain the best time resolution. [ABSTRACT FROM AUTHOR]

Recently developed ceramic and single crystal Cerium-doped gadolinium aluminum gallium garnet (GAGG:Ce) scintillators were studied. We compared their scintillation properties with samples of the same 5 × 5 × 5 mm 3 size. In photoluminescence emission spectra, ceramic and single crystal GAGG:Ce showed intense emission peak at 555 nm and 515 nm, respectively, ascribed to 5d–4f transitions of Ce 3 +. And the single crystal GAGG:Ce had a weak emission peak appearing at 380 nm. The light yield induced by 137 Cs γ -ray of ceramic was higher than that of single crystal. The afterglow of ceramic GAGG:Ce was shorter than that of single crystal after illumination. At room temperature, single crystal GAGG:Ce was more severely affected by thermoluminescence than ceramic GAGG:Ce. The primary decay time of ceramic and single crystal under γ -ray was 182.9 ns and 50.1 ns, respectively. Furthermore, the fast component of decay time was found in single crystal. This research can lay the foundation for the preparation of better GAGG:Ce scintillators in the future. • The scintillation properties of ceramic and single crystal GAGG:Ce were compared. • At room temperature, the afterglow of ceramic GAGG:Ce decreased faster. • Ceramic GAGG:Ce exhibited higher light yield and better energy resolution. • A fast decay time component was found in the single crystal GAGG:Ce. [ABSTRACT FROM AUTHOR]

The large size (4 cm × 4 cm × 1 cm) Ce3+-doped high gadolinium oxyfluoride glass with density of 5.83 g/cm³ was prepared by the melt quench method at 1220 °C. The glass is colorless and transparent over the visible range. The prolonged decay time under 275 nm UV light demonstrates the energy transfer from Gd3+ ions to Ce3+ ions. The X-ray excited luminescence spectra (XEL) show the emission peak corresponds to the 5d→4f transitions of Ce3+ ion. The integral emission intensity of glass was compared with that of bismuth germanate oxide (BGO) crystals. The scintillation property of glass was studied under the γ -ray from 137Cs source and a clear energy peak was observed with light yield (LY) over 1100 ph/MeV. The scintillation decay time comprises fast and slow components. All results presented in this work indicate the appropriate potential to be high-energy rays detecting material for CEPC. [ABSTRACT FROM AUTHOR]

The Circular Electron Positron Collider (CEPC) is a large international scientific facility proposed by the Chinese particle physics community. For the particle flow algorithms (PFA) oriented HCAL of the CEPC, an analog read-out option (AHCAL) is chosen in this regard. The proposal of silicon photomultiplier (SiPM) coupling with the glass scintillator as the detection unit HCAL is a new solution for the next generation calorimeter. The optical and scintilation characteristics of the aluminoborosilicate glass scintillator have been measured. When the wavelength is longer than 450 nm, the transmittance of the aluminoborosilicate glass is higher than 65%. In X-ray excited luminescence spectra, the integral intensity of the glass is 25.5% that of Bi 4 Ge 3 O 12 (BGO) crystal. The energy resolution of the glass is approximately 27%. Moreover, the light yield of the glass is greater than 800 ph/MeV. The scintillating decay time of the fast and slow components is 262.10 ns (18%) and 1234.83 ns (82%), respectively. The difference between the scintillating and fluorescence decay time of the glass is explained by the luminescent mechanism. In addition, the afterglow of the glass was tested. • A new solution for coupling a silicon photomultiplier (SiPM) to a glass scintillator as a hadron calorimeter of CEPC is proposed. • Optical and scintillation properties of the aluminoborosilicate glass were evaluated. • The scintillation light yield is higher than 800 ph/MeV, and the energy resolution is 26.77%. [ABSTRACT FROM AUTHOR]

The excellent jet energy resolution is crucial for the precise measurement of the Higgs properties at future e + e − Higgs factories, such as the Circular Electron Positron Collider (CEPC). For this purpose, a novel design of the particle flow oriented hadronic calorimeter based on glass scintillators (GSHCAL) is proposed. Compared with the designs based on gas or plastic scintillators, the GSHCAL can achieve a higher sampling fraction and more compact structure in a cost-effective way, benefiting from the high density and low cost of glass scintillators. In order to explore the physics potential of the GSHCAL, its intrinsic energy resolution and the contribution to the measurement of the hadronic system was investigated by Monte Carlo simulations. Preliminary results show that the stochastic term of hadronic energy resolution can reach around 24% and the Boson Mass Resolution (BMR) can reach around 3.38% when the GSHCAL is applied. Besides, the key technical R&D of high-performance glass scintillator tiles is also introduced. [ABSTRACT FROM AUTHOR]

The performance of two 6Li enriched elpasolite scintillators Cs 2 LiYCl 6 : Ce 3 + (CLYC) and Cs 2 LiLaBr 6 : Ce 3 + (CLLB) were investigated using mono-energetic fast neutrons generated by a 3 MV tandem accelerator. The Pulse Shape Discrimination (PSD) ability, response and energy resolution to fast neutrons and scattered slow neutrons were studied. The 6Li enriched CLYC had excellent discrimination ability between neutron and gamma rays with the Figure of Merit (FOM) value better than 2.4. An Artificial neural network (ANN) model could discriminate fast neutrons and scattered slow neutrons effectively with an accuracy of 97%, which render the Li-6 enriched CLYC capable to detect thermal neutrons with high efficiency and the energy spectrum of fast neutrons simultaneously. The quenching factors are calculated to be 0.92 and 0.48 for the 35Cl(n, p)35S and 35Cl (n, α)32P reaction, while the detection efficiency is about 0.1%–0.75% for fast neutrons within the energy range of 0.9–5.2 MeV. Unlike CLYC, CLLB was only sensitive to slow neutrons, and the discrimination ability between neutrons and gamma rays is worse than CLYC, while the ANN model exhibit better performance which has an accuracy of 97%. [ABSTRACT FROM AUTHOR]

In this work, Cs 2 LiLaBr 6 :1%Ce (CLLB:Ce) single crystal with the size of Ф26 mm × 80 mm were successfully grown by the Bridgman method. The optimal conditions of application were presented by coupling with R6231-100 PMT. The pulse spectra are recorded by the 4-channel digital converter DT5751 at a sampling rate of 1 GS/s. The energy spectra of the CLLB:Ce crystal were recorded under different PMT gain voltage. The best energy resolution is obtained (up to 3.8%) when the gain voltage of PMT is 3.65V. The non-proportionality of CLLB:Ce crystal was measured under varied radioactive sources while the background radioactive was discussed. Besides, the energy spectra of CLLB:Ce crystal were recorded when the temperature was varied from −30 °C to 50 °C. Finally, the discriminating ability of neutron and gamma was evaluated under 252Cf source and AmBe source, the FOM value is 1.4 and 1.2, respectively, which has a greatly potential application in the nuclear radiation detection. • Cs 2 LiLaBr 6 :1%Ce single crystal with the size of Ф26mm × 50 mm were successfully grown. • Cs 2 LiLaBr 6 :1%Ce has a good non-proportionality (3%). • CLLB:Ce crystal has a best scintillation properties at the temperature of 30 °C. • The FOM value of CLLB:Ce crystal is estimated about 1.4 under 252Cf source. [ABSTRACT FROM AUTHOR]

• A serial of Eu2+-doped CLLB single crystals were successfully grown. • The Eu2+ activated CLLB matrix strategy increases the Stokes shift. • The light yields of CLLB: 2% Eu is 18700ph/MeV under 137Cs source at 662 keV. • CLLB: Eu crystal has the application potential of long afterglow X-ray imaging. In this work, a novel single crystal scintillator, Eu2+-doped Cs 2 LiLaBr 6 (CLLB: Eu) with Ф12 mm × 50 mm, was successfully grown by the Bridgman method. The effects of substitution amount of europium ions on the crystal structure, luminescent properties and scintillation properties were systematically studied by fluorescence spectroscopy, XEL, decay kinetics, and temperature-dependent emission spectra. The Cs 2 LiLaBr 6 :2%Eu sample presents the highest light yield under X-ray excitation, which is about 235 times that of commercial BGO single crystals. The nanosecond decay lifetime of Eu2+ was observed in Cs 2 LiLaBr 6 :Eu crystal. The afterglow result indicates that the Cs 2 LiLaBr 6 : Eu crystal has a long afterglow and the afterglow mechanism of Cs 2 LiLaBr 6 : Eu crystal was proposed and constructed. It has a potent application in nuclear radiation detection and imaging as a scintillation long afterglow material. [ABSTRACT FROM AUTHOR]

Three series of Dy3+-, Tb3+-doped and Tb3+/Dy3+ co-doped 40TeO 2 -20(Gd,Lu) 2 O 3 –40WO 3 glasses with density of about 6.75 g/cm3 were successfully prepared by high temperature melt-quenching method. The luminescence properties of these rare earth ions doped 40TeO 2 -20(Gd,Lu) 2 O 3 –40WO 3 glass were systematically studied by transmittance, photoluminescence (excitation and emission spectra), time-resolved emission spectra (TRES) and X-ray excited luminescence (XEL) spectra, together with the luminescence decay curves. The optimal doping concentration of Dy3+ and Tb3+ ions in 40TeO 2 -20(Gd,Lu) 2 O 3 –40WO 3 glasses was determined under UV and X-ray excitation, respectively. It is found there is an efficient energy transfer from Dy3+ to Tb3+ ions in 40TeO 2 -20(Gd,Lu) 2 O 3 –40WO 3 glass in photoluminescence spectra. However, it is not true under X-ray excitation due to the complicated physical process. • The density of Dy3+-, Tb3+-doped and Tb3+/Dy3+ codoped 40TeO 2 -20(Gd,Lu) 2 O 3 –40WO 3 scintillation glasses is up to 6.75 g/cm3. • The energy transfer process of Dy3+.→Tb3+ was confirmed through photoluminescence spectra, luminescence decay curves and TRES spectra. • The energy transfer efficiency of Dy3+ ions to Tb3+ ions is up to 97.6%. • The difference of energy transfer effect between XEL and PL process was explored. [ABSTRACT FROM AUTHOR]

With the proposal of the road map of Time-of-Flight positron emission tomography (TOF-PET) with a Coincidence Time Resolution (CTR) of 10 ps by Paul Lecoq et al. in 2020, the technology based on TOF puts forward higher requirements on the performance of its core optical devices. In this manuscript, we developed a kind of Multi-Anode micro channel plate photomultiplier tube (MCP-PMT) based on Cherenkov radiator window. By using the Cherenkov radiator as the optical window of Multi-Anode MCP-PMT directly, the optical interface between the scintillator and the PMT window in conventional TOF-PET is eliminated, reducing light loss and further improve the time resolution of TOF-PET. The anode of this MCP-PMT can be split into a finely spaced array of collecting electrodes to achieve good positional sensitivity. In this paper, the single photon detection capability and time resolution of this kind of MCP-PMT are evaluated. The transit time spread (TTS) at single photon mode can reach 42.9 ps, and the TTS at multi photon mode is less than 10 ps. The CTR based on this kind of MCP-PMT is 156.7 ± 10.6 ps FWHM, which is equivalent to a position resolution of 23.5 ± 1.6 mm along a line of response (LOR). The performance uniformity of this kind MCP-PMT has also been calibrated. • A new Multi-anode MCP-PMT with Cherenkov Radiator Window. • The time resolution of this kind of MCP-PMT is less than 40 ps sigma. • The coincidence time resolution based on this kind of MCP-PMT is 156.7 ps FWHM. • This kind of multi-anode MCP-PMT shows great uniformity in gain and time resolution. [ABSTRACT FROM AUTHOR]

The development of plastic scintillators loaded with low-cost phosphorescent sensitizer is currently an important topic toward enhancing the scintillation light yield for radiation detection applications. In this work, we report plastic scintillators loaded with deep-blue-emitting phosphorescent sensitizer CuI(PPh 3) 2 (t -BuPy), where PPh 3 and t -BuPy stand for triphenylphosphine and 4- tert -butylpyridine, respectively. CuI(PPh 3) 2 (t -BuPy)-loaded poly(vinyltoluene)-based plastic scintillators with high optical transmittance of over 80% were synthesized via bulk polymerization method. The optical absorption, photoluminescence spectra, decay kinetics, and scintillation performance under X-ray, γ-ray, and α-particle excitation were comprehensively investigated. The scintillation yield was reduced with the increase of CuI(PPh 3) 2 (t -BuPy) loading concentration. The physical mechanism and the role of the copper iodide complex in scintillation yield reduction are proposed. [Display omitted] • Poly(vinyltoluene)-based plastic scintillators loaded with phosphorescent sensitizer CuI(PPh 3) 2 (t -BuPy) were synthesized. • The scintillation yield of PVT scintillators is reduced with the increase of CuI(PPh 3) 2 (t -BuPy) loading concentration. • The scintillation yield reduction is associated with the nonradiative dissipation of energy from CuI(PPh 3) 2 (t -BuPy). • Plastic scintillator containing only CuI(PPh 3) 2 (t -BuPy) showed α/γ PSD performance. [ABSTRACT FROM AUTHOR]