Barium fluoride (BaF2) crystal has received significant attention in high-energy physics due to its unique sub-ns ultrafast scintillation component. Previous studies have demonstrated that slow scintillation component in BaF2 crystal can be effectively suppressed through yttrium (Y) doping. Although crack-free growth of 10 at%Y-doped BaF2 crystals with cross-sections up to 35 x 35 mm(2) have been achieved, high-concentration Y-doped BaF2 crystals with large size are difficult to obtain due to cracking arising from thermal stress and mechanical stress caused by segregation of Y. This study aims to address cracking issues in Y-doped BaF2 crystals through integrated thermophysical analysis and experimental parameter optimization. Upon comparing the thermophysical properties of undoped and Y-doped BaF2 crystals, the impact of a high concentration of Y-doping was studied quantitatively, thereby establishing a criterion for thermal field tolerance. Significantly, the critical strain threshold was determined based on experimental cracking results, from which optimized parameter boundaries were derived. Through iterative experimental refinement, we successfully achieved crack-free growth of 4-inch BaF2 crystals with 15 at%Y doping. The grown crystal exhibits good optical homogeneity, maintaining > 90% transmittance across most of the visible spectrum. This parameter optimization framework demonstrates transferability for large-scale doped crystal growth systems.

Thermal neutron technology is widely applied in many fields, such as homeland security, nuclear non-proliferation, nuclear energy development, industrial nondestructive testing, and nuclear physics research. However, existing commercially available thermal neutron detection materials currently still face many developmental challenges in terms of detection performance and manufacturing costs. In this study, a series of organic-inorganic composite scintillators sensitive to thermal neutrons was prepared via solid-state reaction by uniformly dispersing 0-20% (in mass) of LiF-CaF2:Eu eutectic powder in organic polystyrene matrixes. X-ray diffraction patterns, scanning electron microscope morphologies, and elemental distributions of the synthesized LiF-CaF2:Eu eutectic powder were analyzed. The radioluminescence and optical transmittance of the prepared composite scintillators were evaluated, and comparisons were made between LiF-CaF2:Eu eutectic powder and LiF-CaF2:Eu mixed powder as inorganic additives. Using cadmium difference method and pulse shape discrimination technologies, the thermal neutron detection performance of composite scintillators loaded with LiF-CaF2:Eu (natural Li abundance) and( 6)LiF-CaF2:Eu (95% enriched Li-6) eutectic powder was systematically investigated. Compared to composites filled with LiF-CaF2:Eu mixed powder, those filled with LiF-CaF2:Eu eutectic powder exhibited better optical transmittance and higher radioluminescence intensity, which increased with the addition of more eutectic powder. Increasing the abundance of Li-6 can effectively improve thermal neutron detection efficiency, and figure of merit for thermal neutron/gamma discrimination in composite scintillators can reach 2.64. As a promising novel scintillator for thermal neutron detection, the composite scintillators loaded with LiF-CaF2:Eu eutectic powder show excellent thermal neutron detection and thermal neutron/gamma discrimination.

High-speed Ge/Si integrated photodetectors are essential for spaceborne photonic links, yet proton irradiation can strongly increase leakage current and noise, compromising long-term reliability. Here, we performed a broad-spectrum proton-irradiation study on high-speed Ge/Si integrated photodetectors and validated hydrogen loading as a radiation-hardening approach. An RCF-calibrated energy-fluence spectrum combined with Geant4 energy-deposition simulations enabled dose-calibrated testing at cumulative deposited doses of 158, 316, 790, and in the silicon layer under a laser-plasma-driven broadband proton beam with a maximum energy of . For untreated devices, the bandwidth decreased from to at , whereas the dark current at a reverse bias increased from to its preirradiation level. Hydrogen-loaded devices remained functional and exhibited improved tolerance, retaining bandwidth ( of the preirradiation reference) while limiting the dark-current increase to at . This demonstrates a practical hardening route for space-relevant integrated photodetectors.

Barium fluoride (BaF2) crystal is an ultrafast scintillator known for a sub-nanosecond fast component. Recent studies have shown that yttrium (Y) doping effectively suppresses the slow scintillation component. In this study, we comprehensively investigate the impact of Y doping by growing BaF2 crystals with nominal Y concentrations in the range of 0-20 at%. The actual Y concentration in BaF2:Y crystal samples was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES), and the optical transmittance (OT), radioluminescence (RL), fast/slow component ratio (F/S) of light output (LO), energy resolution (ER), and decay time (DT) were systematically measured. It was found that Y doping influences not only the LO and F/S but also the DT of BaF2 crystals. As the doping concentration increased from 0% to 20 at%, the LO intensity of the slow component decreased to 6% of that of undoped crystal, while that of the fast component reduced to 60% of undoped crystal. Consequently, the F/S increased from 0.13 to 1.36, whereas ER@511keV degraded from 12.1% to 38.7%. The LOs of slow and fast components showed distinct trends: the slow component decreased rapidly below 1 at% Y and then decayed with an offset-exponential trend, while the fast component remained up to 2 at% before declining linearly. The slow component in Y-doped BaF2 crystals consists of two distinct decay processes: the slower one that decreases from 755 to 381 ns, and the faster one that declines from 199 to 41 ns upon doping with Y.

Bismuth silicate (Bi4Si3O12, BSO) crystals, due to their high stopping power, fast decay, and low raw material cost, are expected to be applied in future high-energy physics (HEP) experiments. However, the high-quality and large crystal growth have restricted its practical HEP applications as a cost-effective scintillator. In this study, BSO crystals with dimensions up to 22.6 & times; 22.6 & times; 369 mm(3) (SIC-BSO-369) and 18.6 & times; 18.6 & times; 259 mm(3) (SIC-BSO-259) were successfully grown. These are the longest BSO single crystals reported to date. Their scintillation properties were measured, including transmittance, photoluminescence (PL), X-ray excited emission, energy resolution (ER), and light response uniformity (LRU). The results show that the SIC-BSO-259 crystal exhibits a high longitudinal transmittance (78.32%@480 nm) close to the theoretical limit value, demonstrating excellent optical quality. Due to internal scattering, the longitudinal transmittance of the SIC-BSO-369 crystal is 45.27% at 480 nm. The average ER of the SIC-BSO-259 and SIC-BSO-369 for 662 keV gamma rays are 27.2% and 29.0%, respectively. And their average absolute light output (LO) are 776 and 735 ph/MeV, respectively. The optimal LRU (delta value) of SIC-BSO-259 is-0.52% +/- 0.5% with a combination of all polished surfaces and ESR as high-reflector material, while for SIC-BSO-369 is 1.41% +/- 1.8% with Tyvek wrapped.

Barium fluoride (BaF2) crystal is an ultrafast scintillator known for a sub-nanosecond fast component. Recent studies have shown that yttrium (Y) doping effectively suppresses the slow scintillation component. In this study, we comprehensively investigate the impact of Y doping by growing BaF2 crystals with nominal Y concentrations in the range of 0 to 20 at%. The actual Y concentration in BaF2:Y crystal samples was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES), and the optical transmittance (OT), radioluminescence (RL), fast/slow component ratio (F/S) of light output (LO), energy resolution (ER), and decay time (DT) were systematically measured. It was found that Y doping influences not only the LO and F/S but also the DT of BaF2 crystals. As the doping concentration increased from 0% to 20 at%, the LO intensity of the slow component decreased to 6% of that of undoped crystal, while that of the fast component reduced to 60% of undoped crystal. Consequently, the F/S increased from 0.13 to 1.36, whereas ER@511keV degraded from 12.1% to 38.7%. The LOs of slow and fast components showed distinct trends: the slow component decreased rapidly below 1 at% Y and then decayed with an offset-exponential trend, while the fast component remained up to 2 at% before declining linearly. The slow component in Y-doped BaF2 crystals consists of two distinct decay processes: the slower one that decreases from 755 ns to 381 ns, and the faster one that declines from 199 ns to 41 ns upon doping with Y.

Optimized surface polishing effectively reduces surface damage and defects in CsPbBr 3 single crystals, suppressing leakage current and electronic noise and thereby significantly enhancing γ-ray energy resolution.

X-ray communication offers significant advantages over traditional microwave methods due to its shorter wavelength and higher theoretical bandwidth, enabling efficient space communication and penetration through complex electromagnetic environments. However, current systems face limitations in X-ray emission modulation and high-precision timing detection. To meet the high-frequency transmission demands of space missions, we developed a pulsed X-ray emission source capable of high-frequency modulation. Additionally, we identified specific scintillators with distinct advantages for different transmission frequency ranges, allowing for performance optimization. Experimental results demonstrated a successful transmission rate of 10 MHz, validating the feasibility of MHz-frequency X-ray communication.

We report the scintillation and timing performance of a new developed 200 * 20 mm * 20 mm large size barium fluoride crystal doped with 3at (BaF2:Y) to enhance the application for high time resolution. This doping effectively suppresses the slow scintillation component while maintaining most of the fast component, as confirmed by X-ray excited luminescence measurements. The BaF2:Y crystal demonstrated a transmittance of near 90 spectrum and a light response uniformity parameter of delta = (-2.74 +- 1.15) when coupled with the tail end. The actual yttrium content varied from 2.1at near the seed end to 3.7at detector with silicon photomultipliers exhibited a time resolution of (82.2 +- 2.6) ps using constant fraction discrimination method in a cosmic ray test and (140.1 +- 3.8) ps using a low fixed threshold method in a beam test at Shanghai Synchrotron Radiation Facility with an 1.35 GeV electron beam. These results indicate the significant potential of BaF2:Y crystal for various applications, such as detectors for particle physics and nuclear physics.

Future high-performance particle colliders, e.g., the proposed circular electron positron collider (CEPC) or future circular collider (FCC), demand unprecedented levels of accuracy in energy measurement for calorimeters. Although the proposed high-granularity crystal electromagnetic calorimeter has made great progress in recent years, the designing and matching of Bi4Ge3O12 (BGO) scintillators with lower light output and higher radiation resistance, as well as not introducing slow components, lag far behind. Here, a Mn-doped BGO powder exhibits robust radiation resistance with a faster decay time, accelerating by 15%. Doping with Mn3% reduces the intensities of photoluminescence (PL) and radioluminescence (RL) to 55% and 22%, respectively, of those observed in pure BGO powder. Furthermore, Mn-doped BGO exhibits enhanced radiation resistance and can maintain 72% of the initial RL intensity within 2 h of radiation with a high-power UV lamp, while that of pure BGO is severely degraded to 45%. Theoretical calculation mechanism studies show that Mn doping not only maintains the intrinsic luminescence of BGO but also introduces a new intermediate energy level in the energy band to inhibit the formation of color centers. This work provides a new avenue to search for or discover scintillators from existing cost-effective scintillators for future high-energy physics experiments.

A high-granularity crystal calorimeter (HGCCAL) has been proposed for the future Circular Electron Positron Collider (CEPC). This study investigates the time resolution of various crystal - Silicon Photomultiplier (SiPM) detection units for HGCCAL, focusing on Bismuth Germanate (BGO), Lead Tungstate (PWO), and Bismuth Silicon Oxide (BSO) crystals. Beam tests were conducted using 10 GeV pions at CERN and 5 GeV electrons at DESY, enabling systematic comparisons of timing performance under both minimum ionizing particle (MIP) signals and electromagnetic (EM) showers. Three timing methods - constant fraction timing (CFT) with sampled points, linear fitting, and exponential fitting - were evaluated, with an exponential fit combined with a 10 providing the best time resolution. Measurements of crystal units with different dimensions revealed that both scintillation light yield and signal rise time influence timing performance. Among similarly sized crystals, PWO exhibited the best time resolution due to its fast signal rise time, while BGO and BSO demonstrated comparable timing performance. For long BGO bars (40 cm and 60 cm), the time resolution remained uniform along their length, achieving approximately 0.75 ns and 0.95 ns for MIP signals. Under intense EM showers, both bars reached a timing resolution of approximately 200 ps at high amplitudes. And the presence of upstream pre-shower layers can introduce additional timing fluctuations at similar amplitudes.

Core-valence luminescence (CVL) in Cs2ZnCl4, typically characterized by a subnanosecond decay time, holds great value in the field of ultrafast scintillation applications. However, its light yield is comparatively low, and the underlying regulatory mechanism of CVL remains inadequate. In this work, the study revealed the inherent origin and enhancement regulation mechanism of CVL in F-- or Rb+-doped Cs2ZnCl4 single crystals. The doped Cs2ZnCl4 showed red-shifted emission at 223 nm excitation with an enhanced Stokes shift, effectively reducing self-absorption. Rb+ doping introduced deeper Rb 4p orbitals, which hindered hole participation in CVL. In contrast, F- doping introduced F 2p orbitals in the valence band, narrowing the core valence gap while broadening Cs 5p and Zn 3d levels, thereby enhancing the electron-hole recombination efficiency. Consequently, the light yield increased by 24% compared with pure Cs2ZnCl4. Remarkably, the radioluminescence (RL) intensity of Cs2ZnCl4:F was significantly enhanced under X-ray excitation while preserving its ultrafast decay characteristics (1.83 +/- 0.006 ns). This work provides new insights into the modulation mechanisms of CVL and advances the rational design of CsCl-based halides for ultrafast scintillators.

An as-grown 1-inch-diameter Cs 2 ZnCl 4 crystal boule in a quartz ampoule (a), a polished Cs 2 ZnCl 4 crystal with dimensions of 10 × 10 × 11 mm 3 , and a diagram illustrating the crystal growth process (c).

Cesium iodide crystals with large sizes are highly desirable for X-ray and gamma-ray detection applications. In this study, we have designed a simple and convenient continuous-mass transport process (CMTP) method to obtain large-size, high-quality pure CsI and Tl doped CsI crystals for the first time. This method allows for a continuous replenishment of the raw materials required for crystal growth in the growth container through a solute diff usion process, facilitating the stable growth of large single crystals (up to a size of 23.5 x 21 x 8 mm3). Furthermore, by adjusting the temperature difference between the growth and supplement containers, it is feasible to control the crystal growth rate. Compared with the inverse temperature crystallization (ITC) method, Tl doped CsI crystals grown by the CMTP method exhibit better crystallization quality, with both smaller values and narrower fluctuations for full width at half maximum (FWHM) in the X-ray rocking curve, and achieve comparable energy resolution (6.20 %-6.73 %), decay time (649-657 ns), afterglow level (0.1 % @ 68-98 ms), and higher light yield (78,000-83,000 photons/MeV). Our work provides a promising strategy for the preparation of larger-sized Tl doped CsI single crystals via the CMTP method.

We report the scintillation and timing performance of a newly developed 200 mm× 20 mm× 20 mm large size barium fluoride crystal doped with 3 at% yttrium (BaF 2 :Y) to enhance the application for high time resolution. This doping effectively suppresses the slow scintillation component while maintaining most of the fast component, as confirmed by X-ray excited luminescence measurements. The BaF 2 :Y crystal demonstrated a transmittance of near 90% in the visible spectrum and a light response uniformity parameter of δ = (-2.74 ± 1.15)% when coupled with the tail end. The actual yttrium content varied from 2.1 at% near the seed end to 3.7 at% at the tail end. The assembled large BaF 2 :Y detector with silicon photomultipliers exhibited a time resolution of 82.2 ± 2.6 ps using constant fraction discrimination method in a cosmic ray test and 140.1 ± 3.8 ps using a low fixed threshold method in a beam test at Shanghai Synchrotron Radiation Facility with a 1.35 GeV electron beam. These results indicate the significant potential of BaF 2 :Y crystal for various applications, such as detectors for particle physics and nuclear physics.

CsPbBr3 single crystal is a promising candidate for room temperature radiation detector. However, the experimental mobilities reported exhibit considerable discrepancy, ranging widely from 10 to 4500 cm2/(V · s) at room temperature. Here, vertical Bridgman grown CsPbBr3 single crystal has been used to measure the mobility accurately using pulse-biased time-of-flight method. The hole mobility for CsPbBr3 at room temperature is modest to be around 25 cm2/(V · s). The value of the corresponding power-law index n for hole mobility on temperature (μ ∼ T-n) is around −1.23 in the range of 155–350 K, which is well consistent with the previous FET and Hall effect measurements, as well as theoretical calculations. The polar optical phonon rather than acoustic phonon is confirmed to be responsible for scattering carriers at room temperature. Our study gives solid evidence on the modest mobility in the intrinsic (not dominated by defects) CsPbBr3 semiconductor, which may limit the application of CsPbBr3 in high flux photon counting detectors.

Cs3Cu2I5 halide perovskites doped with luminescence activators have unique optical and electronic properties; however, they tend to combine with slow scintillation decay, which leads to ghosting or blurriness during X-ray imaging. In this study, we produced magnesium (Mg2+)-doped Cs3Cu2I5 single crystals (SCs) with blue emission at 440 nm, and the photoluminescence quantum yields ranged from 72.4 to 81.7%. Moreover, enhanced radioluminescence (RL) intensity and light output were achieved without deteriorating scintillation decay compared to those of pure Cs3Cu2I5 SCs. Mg doping can strengthen electron-phonon coupling, and the emission (2.15 eV) at a low temperature (80-290 K) showed the presence of additional carrier capture channels of Mg-related defect levels in the band gap, which can help reduce the probability of nonradiative recombination. Therefore, flexible X-ray scintillator films with excellent hydrophobicity were fabricated using Mg2+-doped Cs3Cu2I5 SC powders, and their spatial resolution (2.5 Lp/mm) met the resolution requirements of commercial spiral computed tomography. This study found an effective strategy for enhancing the self-trapped exciton emission of metal copper-based halide scintillators and highlighted their applicability in low-dose flexible X-ray detection and imaging.