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Ce‐doped Cs2LiLaBr6 (CLLB) scintillator crystals, known for their superior neutron/gamma dual‐mode detection capability and exceptional scintillation properties, have garnered significant attention for both fundamental science and practical applications. The role of Ce3+ cations as luminescent centers is pivotal, influencing the scintillation properties as their concentration varies. While the effects of Ce3+ concentration on scintillation performance are well‐documented, the ramifications for crystalline structure remain less explored. In this study, high‐quality CLLB:Ce single crystals are fabricated(atomic packing factor of maximum doped Ce is 0.04%) using the vertical Bridgman (VB) method and subsequently characterized their crystalline structure by neutron diffraction, X‐ray diffraction (XRD), and elemental analysis. The findings reveal a correlation between Ce3+ concentration and the crystal cell parameters, presenting intriguing deviations from Vegard's law. Such observations suggest the potential presence of alternative defects, potentially Li+ interstitials, in CLLB:Ce. This work offers critical insights for advancing the understanding and optimization of CLLB:Ce scintillators. [ABSTRACT FROM AUTHOR]

In this study, highly (Y 0.99−x Gd x Sm 0.01) 2 O 3 transparent ceramics with varying Gd3+ content (x = 0–0.1) was successfully fabricated by vacuum sintering. The effect of the Gd3+ content on the structural, mechanical and optical properties of the Y 2 O 3 ceramics were systematically investigated. The prepared transparent ceramics have high optical quality with an in-line transmittance of 75.16%− 81.44% at 610 nm (4G 5/2 →6H 9/2 transitions of Sm3+). Mechanical properties, including Vickers hardness (HV), are also evidently enhanced by solid solution strengthening. Photoluminescence properties of ceramics including excitation spectra, emission spectra and fluorescence lifetimes are systematically investigated. Notably, the photoluminescence properties of the ceramics, including excitation spectra, emission spectra and fluorescence lifetimes, confirm the existence of energy transfer (ET) from Gd3+ to Sm3+ ions and provide a qualitative understanding of the ET process. The efficiency of ET between Gd3+ and Sm3+ emission centers was found to increase with higher Gd3+ concentration. This work may provide guidance on the design, preparation and application of Gd-doped transparent ceramic scintillators. [ABSTRACT FROM AUTHOR]

Gamma-ray spectroscopy is an effective technique for radioactive material characterization, routine inventory verification, nuclear safeguards, health physics, and source search scenarios. Gamma-ray spectrometers typically cannot be operated in the immediate vicinity of nuclear reactors due to their high flux fields and their resulting inability to resolve individual pulses. Low-power reactor facilities offer the possibility to study reactor gamma-ray fields, a domain of experiments hitherto poorly explored. In this work, we present gamma-ray spectroscopy experiments performed with various detectors in two reactors: The EPFL zero-power research reactor CROCUS, and the neutron beam facility at the Ohio State University Research Reactor (OSURR). We employed inorganic scintillators (CeBr3), organic scintillators (trans-stilbene and organic glass), and high-purity germanium semiconductors (HPGe) to cover a range of typical—and new—instruments used in gamma-ray spectroscopy. The aim of this study is to provide a guideline for reactor users regarding detector performance, observed responses, and therefore available information in the reactor photon fields up to 2 MeV. The results indicate several future prospects, such as the online (at criticality) monitoring of fission products (like Xe, I, and La), dual-particle sensitive experiments, and code validation opportunities. [ABSTRACT FROM AUTHOR]

Er3+ doped high density germanate glasses with compositions of 50GeO 2 -10BaO–10Al 2 O 3 -15Lu 2 O 3 -(15-x) La 2 O 3 -xEr 2 O 3 (x = 0, 0.1, 0.5, 1.0, 1.5, and 2.0, in mol%) have been prepared by the melt-quenching method. The optical and physical properties of the samples were characterized by differential scanning calorimetry (DSC), density, transmittance spectra, photoluminescence (PL) spectra, and X-ray excited luminescence (XEL) spectra. The densities were in the range from 5.90 to 6.07 g/cm3. The strong green emissions around 552 nm of Er3+ were observed upon the excitations of 378 nm light and the X-ray, and the lifetimes of 552 nm emission were in the range of 20.88–96.47 μs. The results show that Er3+ doped high density germanate glasses could be used as potential scintillators for X-ray CT. [ABSTRACT FROM AUTHOR]

The Trans-Iron Galactic Element Recorder (TIGER) family of instruments is optimized to measure the relative abundances of the rare, ultra-heavy galactic cosmic rays (UHGCRs) with atomic number (Z) Z ≥ 30. Observing the UHGCRs places a premium on exposure that the balloon-borne SuperTIGER achieved with a large area detector (5.6 m2) and two Antarctic flights totaling 87 days, while the smaller (∼1 m2) TIGER for the International Space Station (TIGERISS) aims to achieve this with a longer observation time from one to several years. SuperTIGER uses a combination of scintillator and Cherenkov detectors to determine charge and energy. TIGERISS will use silicon strip detectors (SSDs) instead of scintillators, with improved charge resolution, signal linearity, and dynamic range. Extended single-element resolution UHGCR measurements through 82Pb will cover elements produced in s-process and r-process neutron capture nucleosynthesis, adding to the multi-messenger effort to determine the relative contributions of supernovae (SNe) and Neutron Star Merger (NSM) events to the r-process nucleosynthesis product content of the galaxy. [ABSTRACT FROM AUTHOR]

The search for low-energy antideuterons in cosmic rays allows the addressing of fundamental physics problems testing for the presence of primordial antimatter and the nature of Dark Matter. The PHeSCAMI (Pressurized Helium Scintillating Calorimeter for AntiMatter Identification) project aims to exploit the long-living metastable states of the helium target for the identification of low-energy antideuterons in cosmic rays. A space-based pressurized helium calorimeter would provide a characteristic identification signature based on the coincident detection of a prompt scintillation signal emitted by the antideuteron energy loss during the slowing-down phase in the gas, and the (≈µs) delayed scintillation signal provided by the charged pions produced in the subsequent annihilation. The performance of a high-pressure (200-bar) helium scintillator prototype, tested in the INFN-TIFPA laboratory, will be summarized. [ABSTRACT FROM AUTHOR]

The radioluminescent (RL) dosemeter is excellent for real-time radiation measurement and can be used in various applications. A plastic scintillator is often the choice sensor because of its size and tissue equivalency. This study aims to characterise a novel plastic scintillator irradiated with high-energy photon beams. An RL dosimetry system was developed using the plastic scintillator. The RL dosimetry system was irradiated using a linear accelerator to characterise the dose linearity, dose rate, energy dependency and depth dose. The developed system showed a linear response toward the dose and dose rate. An energy dependency factor of 1.06 was observed. Depth dose measurement showed a mean deviation of 1.21% from the treatment planning system. The response and characteristics of the plastic scintillator show that it may be used as an alternative in an RL dosimetry system. [ABSTRACT FROM AUTHOR]

Broadband emissive perovskites are next‐generation materials for solid‐state lighting and radiative detection. However, white‐emitting perovskites are generally synthesized by regulating B/X sites, while not enough attention is paid to the A‐site, which is thought to hardly affect the band‐edge structures and optoelectronic properties. Here, a series of Sb3+‐doped In‐based 0D halide perovskite derivatives are described with various organoammonium cations in A‐sites. Warm‐white light emitting across the visible spectrum (450–850 nm), large Stokes shifts, and high photoluminescence quantum yields are easily tunable by molecularly tailoring A‐site cations. These features enable a light yield up to 60976 Photons/MeV as X‐ray scintillator, and a detection limit of 90 nGyair/s that is ≈60 times lower than the medical requirement. It is proved that A‐site plays a critical role in determining the degree of distortion of polyhedra, which influences the broadband photoluminescence and self‐trapped exciton (STE) dominates the emission process. Moreover, for the first time, via the incorporation of 2,6‐dimethylpiperazine, a mixed A‐site regulating strategy produces a standard white‐light emission, which originates from the blue‐light and yellow‐light related to various STE emission centers. It is foreseen that this strategy highlights the expanded role of A‐site and the importance of rethinking A‐sites in perovskites. [ABSTRACT FROM AUTHOR]

Commercial white light-emitting diodes (WLEDs) usually face problems such as lack of red emission, color difference caused by different degradation rates of multiphase phosphors and the poor thermal stability of the organic encapsulants. The development of new single-phase phosphors and glass can solve these problems well. Sr 3 B 14 O 24 :RE3+ (RE = Ce, Tb, Sm, Eu) phosphors and glass were synthesized by solid-phase method. The obtained Sr 3 B 14 O 24 :RE3+ (RE = Ce, Tb, Sm, Eu) samples showed multicolor emission including blue, green, orange and red, respectively. The optimal excitation wavelength of these samples was located in the blue or ultraviolet (UV) light regions, which were well matched with the blue-violet light chips to manufacture WLEDs. More interestingly, UV absorption was found in Sr 3 B 14 O 24 :Ce3+/4+ glass samples. The doping of dual-valence cerium ions could enhance the shielding performance in the light of inferences drawn from the UV-Vis absorption and transmission spectra of glass samples. By co-doping different concentrations of Cs+ ions in Sr 3 B 14 O 24 :Ce3+/4+ glass samples, the function of near infrared (NIR) shielding was also realized. As a new optical multifunctional material, rare earth doped Sr 3 B 14 O 24 have great potential for application in WLEDs, UV and NIR shielding. [ABSTRACT FROM AUTHOR]

X‐ray radiography, playing a crucial role in the daily life of humans, extends the application landscapes of perovskites. Lead halide perovskites remain superior candidates because of strong X‐ray absorption and effective conversion of X‐ray to visible photons. Unfortunately, the perovskites exhibiting efficient band‐edge emission (3D, quasi‐2D or 2D) usually suffer from severe self‐absorption, while the perovskites showing broadband emission with large Stokes shift (0D, 1D or 2D) usually have low quantum yield, long afterglow or poor solution‐processability. Halide‐intercalated perovskites, with incorporated halides in organic layers, exhibit attractive optoelectronic properties due to reduced confinement of excitons, but their development falls far behind due to limited molecular design strategies and wet‐chemistry methods. Here, the use of universal‐wet‐chemistry‐synthesized novel halide‐intercalated perovskites as an efficient X‐ray scintillator for X‐ray imaging is reported. These novel perovskites exhibit superior luminescence by exploiting both free and self‐trapped excitons via halide intercalation. Accordingly, such perovskite scintillators present higher radioluminescence performance compared with conventional perovskite scintillators through enhanced radiative recombination and suppressed self‐absorption simultaneously. With such a scintillator screen, high‐performance X‐ray imaging is demonstrated. The results not only represent a universal synthesis route for the development of perovskites, but also provide valuable guidance for high‐performance X‐ray radiography. [ABSTRACT FROM AUTHOR]

In recent years, hybrid manganese(II) halides (HMHs) have attracted wide attention due to their impressive optical properties, low toxicity, and facile synthetic processibility. Being effective reabsorption-free phosphors, these compounds demonstrate the potential to be used as low-cost solution-processable scintillators. However, most of the HMHs studied to date contain bulk organic cations and, as a result, are characterized by low density and low X-ray stopping power. For this reason, we studied manganese(II) bromides with compact organic cations such as formamidinium (FA+) and acetamidinium (AcA+). In particular, we synthesized four new phases, two of which are characterized by octahedral coordination of manganese ions ((FA)MnBr3 and (AcA)MnBr3) and red emission, whereas the other two have tetrahedrally coordinated Mn2+ ions ((FA)3MnBr5 and (AcA)2MnBr4) and green emission. Photoluminescence (PL) and radioluminescence measurements demonstrated high PL quantum yields and reasonable scintillation light yields of acetamidinium-based compounds. In addition, unlike most known HMH-based scintillators, the discovered materials have a relatively high density due to the small fraction of the volume occupied by organic cations, so their X-ray attenuation coefficients are comparable to the well-known oxide scintillators. [ABSTRACT FROM AUTHOR]

The study of facile‐synthesis and low‐cost X‐ray scintillators with high light yield, low detection limit and high X‐ray imaging resolution plays a vital role in medical and industrial imaging fields. However, the optimal balance between X‐ray absorption, decay lifetime and excitonic utilization efficiency of scintillators to achieve high‐resolution imaging is extremely difficult due to the inherent contradiction. Here two thermally activated delayed fluorescence (TADF)‐actived coinage‐metal clusters M6S6L6 (M=Ag or Cu) were synthesized by simple solvothermal reaction, where the cooperation of heavy atom‐rich character and TADF mechanism supports strong X‐ray absorption and rapid luminescent collection of excitons. Excitingly, Ag6S6L6 (SC‐Ag) displays a high photoluminescence quantum yield of 91.6 % and scintillating light yield of 17420 photons MeV−1, as well as a low detection limit of 208.65 nGy s−1 that is 26 times lower than the medical standard (5.5 μGy s−1). More importantly, a high X‐ray imaging resolution of 16 lp/mm based on SC‐Ag screen is demonstrated. Besides, rigid core skeleton reinforced by metallophilicity endows clusters M6S6L6 strong resistance to humidity and radiation. This work provides a new view for the design of efficient scintillators and opens the research door for silver clusters in scintillation application. [ABSTRACT FROM AUTHOR]

Source localisation and real-time dose verification are at the forefront of medical research in brachytherapy, an oncological radiotherapy procedure based on radioactive sources implanted in the patient body. The ORIGIN project aims to respond to this medical community's need by targeting the development of a multi-point dose mapping system based on fibre sensors integrating a small volume of scintillating material into the tip and interfaced with silicon photomultipliers operated in counting mode. In this paper, a novel method for the selection of the optimal silicon photomultipliers to be used is presented, as well as a laboratory characterisation based on dosimetric figures of merit. More specifically, a technique exploiting the optical cross-talk to maintain the detector linearity in high-rate conditions is demonstrated. Lastly, it is shown that the ORIGIN system complies with the TG43-U1 protocol in high and low dose rate pre-clinical trials with actual brachytherapy sources, an essential requirement for assessing the proposed system as a dosimeter and comparing the performance of the system prototype against the ORIGIN project specifications. [ABSTRACT FROM AUTHOR]

Background: A CZT (cadmium zinc telluride) PET (positron emission tomography) system is being developed at Stanford University. CZT has the promise of outperforming scintillator‐based systems in energy and spatial resolution but has relatively poor coincidence timing resolution. Purpose: To supplement GATE (GEANT 4 Application for Emission Tomography) simulations with charge transport and electronics modeling for a high‐resolution CZT PET system. Methods: A conventional GATE simulation was supplemented with electron‐hole transport modeling and experimentally measured single detector energy resolution to improve the system‐level understanding of a CZT high‐resolution PET system in development at Stanford University. The modeling used GATE hits data and applied charge transport in the crystal and RC‐CR processing of the simulated signals to model the electronics, including leading‐edge discriminators and peak pick‐off. Depth correction was also performed on the simulation data. Experimentally acquired data were used to determine energy resolution parameters and were compared to simulation data. Results: The distributions of the coincidence timing, anode energy, and cathode energy are consistent with experimental data. Numerically, the simulation achieved 153 ns FWHM coincidence time resolution (CTR), which is of the same order of magnitude as the raw 210 ns CTR previously found experimentally. Further, the anode energy resolution was found to be 5.9% FWHM (full width at half maximum) at 511 keV in the simulation, which is between the experimental value found for a single crystal of 3% and the value found for the dual‐panel setup of 8.02%, after depth correction. Conclusions: Developing this advanced simulation improves upon the limitations of GATE for modeling semiconductor PET systems and provides a means for deeper analysis of the coincidence timing resolution and other complementary electron‐hole dependent system parameters. [ABSTRACT FROM AUTHOR]

Angular resolution is crucial for the detailed study of gamma-ray sources and current Cherenkov telescopes (e.g., HESS, MAGIC, and VERITAS) that operate below tens of TeV. Several gamma-ray sources with a photon energy larger than 100 TeV have been revealed by the LHAASO in recent years; the angular resolution of the LHAASO is around  0.3 ∘ . A gamma-ray detector with an angular resolution of less than  0.1 ∘  operating beyond 100 TeV is needed to study the detailed morphology of ultra-high-energy gamma-ray sources further. The cost-effectiveness is crucial for such large-area detectors. In this paper, the impact of telescope aperture, field of view, pixel size, optical point spread function, and signal integration time window on angular resolution is studied. These results can provide essential elements for the design of telescope arrays. [ABSTRACT FROM AUTHOR]

Cloud and bubble chambers have historically been used for particle detection, capitalizing on supersaturation and superheating, respectively. Here, we present new results from a prototype snowball chamber, in which an incoming particle triggers the crystallization of a purified, supercooled liquid. We demonstrate, for the first time, simulation agreement with our first results from 5 years ago: the higher temperature of the freezing of water and significantly shorter time spent supercooled compared to the control in the presence of a Cf-252 fission neutron source. This is accomplished by combining Geant4 modeling of neutron interactions with the Seitz nucleation model used in superheated bubble chambers, including those seeking dark matter. We explore the possible implications of using this new technology for GeV-scale WIMP searches, especially in terms of spin-dependent proton coupling, and report the first supercooling of WbLS (water-based liquid scintillator). [ABSTRACT FROM AUTHOR]

The long-term stability of counters consisting of extruded-scintillator strips and wavelength-shifting fibers was studied. The aging study was carried out for scintillators and wavelength-shifting fibers before starting the mass production of counters. Aging at a higher rate and higher temperatures was used in the study, which was then continued as an interesting R&D work. The decrease in the light yield was at a level of 3% per year during an initial 5–6 years. The aging then proceeds slower and nearly ceases after a 26% decrease over 20 years. The study of preliminarily aged samples was repeated after a 2.5-year pause; it showed that the aging rate for these scintillators was less than 0.5% per year at 20°C. The results obtained over 4.5 years by direct measurements and by using a faster-aging technology were in good agreement. [ABSTRACT FROM AUTHOR]

The first results from the development of previously unknown tellurium-loaded plastic scintillators based on polystyrene, poly(methyl methacrylate), and their copolymers for detectors for the search and study of neutrinoless double beta decay are reported herein. A complex compound of diphenyltellurium oxide with di-(2-ethylhexyl)phosphoric acid and diphenyltellurium di-2-ethylhexanoate were used as tellurium-containing additives. The conditions for obtaining samples have been described and their light yield and transparency has been characterized. [ABSTRACT FROM AUTHOR]

The urgency for cost‐effective, high‐resolution, flexible X‐ray imaging detectors is generating great demand for scintillators with low‐temperature processability, high scintillation yield, and negligible afterglow. X‐ray imaging materials are currently dominated by inorganic scintillators in the form of rigid films and bulk crystals, which have inherent limitations including high‐temperature, complex synthesis, and considerable challenges toward advanced nonplanar imaging. Here, high‐performance and flexible X‐ray scintillators based on novel zero‐dimensional (0D) (BTPP)2MnX4 (BTPP = benzyltriphenylphosphonium; X = Cl, Br) halides are reported. They emit bright green light originating from the 4T1‐6A1 transition of Mn2+ under X‐ray excitation. In particular, (BTPP)2MnBr4 single crystals exhibit excellent air‐ and radiation‐stability, a high scintillation yield of 53 000 photons MeV−1, a low detection limit of 89.9 nGyair s−1, and an ultralow afterglow comparable to commercial Bi4Ge3O12 (BGO) single crystals. Moreover, the (BTPP)2MnCl4@polydimethylsiloxane (PDMS) flexible scintillation screens achieve a high spatial resolution of 14.1 lp mm−1 and realize high‐quality imaging results of nonplanar objects. This study demonstrates that the flexible scintillation screens based on low‐dimensional Mn(II) hybrid halides have significant potential for low‐dose and high‐resolution X‐ray imaging applications. [ABSTRACT FROM AUTHOR]

Radiation detection plays an important role in diverse applications, including medical imaging, security, and display technologies. Scintillators, materials that emit light upon exposure to radiation, have garnered significant attention due to their exceptional sensitivity. Previous research explored polymer dots (P-dots) doped with iridium complexes as nano-sized scintillators for radiation detection, but these were constrained to emitting specific colors like red, green, and blue, limiting their utility. Recently, there has been a breakthrough in the development of white light emitters stimulated by UV–visible light. These emitters exhibit a broad spectral range in the visible wavelength, enhancing contrast and simplifying detection by visible-light sensors. Consequently, the quest for white color scintillators in radiation detection has emerged as a promising avenue for enhancing scintillation efficiency. In this study, we present a novel approach by applying P-dots doped with two iridium complexes to create white light-emitting nano-sized scintillators. These scintillators offer a wider spectral coverage within the visible-light wavelength range. Under UV light (365 nm) excitation, our synthesized P-dots exhibited remarkable white light emission. Moreover, when excited by electron beam irradiation, we observed the clear emission close to white emission which is valuable for improving the detection of radiation. [ABSTRACT FROM AUTHOR]

The B1133+16 pulsar was observed at a frequency of 111 MHz with the BSA radio telescope of the Pushchino Radio Astronomy Observatory from October 2022 to March 2023. Observations were conducted twice a week for two consecutive days. In total, 38 measurements of the scintillation parameters were carried out with a high frequency resolution (up to 65 Hz). We used continuous signal recording in the frequency band of 2.5 MHz. The signal was reconstructed using the coherent dedispersion method. The pulsar's dynamic spectra (DSP) were analyzed using the two-dimensional autocorrelation function (2DACF). The fine frequency structure of the pulsar's scintillation was investigated both through the analysis of time and frequency sections of 2DACF from DSP and through the spectra of individual pulses. The analysis of the frequency sections of the 2DACF showed that the true form of diffractive frequency distortions can be represented by a generalized exponential function with a characteristic frequency width of 1.2 kHz and an index of 0.57. Comparison of scintillation parameters separately for two components of the average profile showed that they are identical for both components. [ABSTRACT FROM AUTHOR]

NaI (Tl) scintillators are widely used because of their characteristics of high detection efficiency, good temporal characteristics, and minimal temperature influence. In order to meet the needs of nuclear radiation detectors with high detection efficiency, large size and high energy resolution NaI (Tl) scintillators are required. Based on the growth characteristics of NaI (Tl) crystals, the main furnace body, temperature field system, crucible, heating power supply and other components of the large size NaI (Tl) growth crystallization furnace were studied and designed. In conjunction with the control system of the large size NaI (Tl) growth crystallization furnace, innovative fusion method was used to grow NaI (Tl) scintillator materials with a diameter exceeding 300 mm, which provides direction and solutions for the subsequent growth of large size NaI (Tl) crystals in China. [ABSTRACT FROM AUTHOR]

High‐pressure chemistry has provided a huge boost to the development of scientific community. Pressure‐induced emission (PIE) in halide perovskites is gradually showing its unique charm in both pressure sensing and optoelectronic device applications. Moreover, the PIE retention of halide perovskites under ambient conditions is of great commercial value. Herein, we mainly focus on the potential applications of PIE and PIE retention in metal halide perovskites for scintillators and solid‐state lighting. Based on the performance requirements of scintillator and single‐component white light‐emitting diodes (WLEDs), the significance of PIE and PIE retention is critically clarified, aiming to design and synthesize materials used for high‐performance optoelectronic devices. This perspective not only demonstrates promising applications of PIE in the fields of scintillators and WLEDs, but also provides potential applications in display imaging and anti‐counterfeiting of PIE materials. Furthermore, solving the scientific disputes that exist under ambient conditions is also simply discussed as an outlook by introducing high‐pressure dimension to produce PIE. [ABSTRACT FROM AUTHOR]

The possibilities of engineering energy losses, created in the cascade process of electron-electron scattering during the interaction of multilayer dielectric structures with ionizing radiation, are considered. It is shown that the contribution of surface plasmons associated with layer boundaries to electron energy losses is significant only for nanometer layer thicknesses and increases with increasing electron energy. At the same time, surface states associated with longitudinal optical phonons in ionic crystals significantly change energy losses during electron thermalization and can lead to an increase in the efficiency and rise rate of scintillation in nanostructured systems. [ABSTRACT FROM AUTHOR]

Medical imaging instrumentation is mostly based on the use of luminescent materials coupled to optical sensors. These materials are employed in the form of granular screens, structured crystals, single transparent crystals, ceramics, etc. Storage phosphors are also incorporated in particular X-ray imaging systems. The physical properties of these materials should match the criteria required by the detective systems employed in morphological and functional biomedical imaging. The systems are analyzed based on theoretical frameworks emanating from the linear cascaded systems theory as well as the signal detection theory. Optical diffusion has been studied by different methodological approaches, such as experimental measurements and analytical modeling, including geometrical optics and Monte Carlo simulation. Analysis of detector imaging performance is based on image quality metrics, such as the luminescence emission efficiency (LE), the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE). Scintillators and phosphors may present total energy conversion on the order of 0.001–0.013 with corresponding DQE in the range of 0.1–0.6. Thus, the signal-to-noise ratio, which is crucial for medical diagnosis, shows clearly higher values than those of the energy conversion. [ABSTRACT FROM AUTHOR]

The 3He gas is commonly used for the detection of thermal neutrons. However, with the depletion of 3He gas, there is a need to develop new solid scintillators for thermal neutron detection. Solid scintillators containing 6Li, which have large neutron capture cross-sections and a large amount of energy released by transmutation reactions, are commonly used as alternative candidates. However, only single-crystal scintillators are currently used, and their 6Li concentration is limited by their chemical composition. In this study, we designed, grew, and evaluated a new eutectic scintillator, Rb2CeCl5/LiCl, which can improve the 6Li concentration compared with single-crystal scintillators. Rb2CeCl5, which was selected as the scintillator phase, has excellent scintillator properties (light yield: 36,000 photons/MeV, decay time: mostly 24 ns, slightly 153 ns), and is less deliquescent than other halide scintillators. The crystal grown using the vertical Bridgman method exhibited a eutectic phase composed of Rb2CeCl5 and LiCl. The eutectic crystals exhibited Ce3+ 5d-4f emissions, with a peak between 360 and 370 nm. The Rb2CeCl5 phase was identified as the luminescent phase via cathodoluminescence mapping, and 16,000 photons/neutron of the light yield and 56.1 ns of the decay time were observed. This study indicates that the Rb2CeCl5/LiCl eutectic scintillator is a promising candidate for use in thermal neutron detectors. [ABSTRACT FROM AUTHOR]

The PEA2PbBr4 scintillator exhibits varied performance in photoluminescence (PL) and radioluminescence (RL) profiles. PL in the reflectivity mode shows emission peaks at 414 and 434 nm, whereas PL and RL in the transmission mode exhibit only one peak at 434 nm. Temperature-dependent PL spectra measurements confirm that self-absorption contributes to this difference. PEA2PbBr4 displays decay times of 1.3 ns (90%) and 4.4 ns (10%) for PL and 11.5 ns (89%) and 47 ns (11%) for RL. To explain the distinct decay times, we construct two models for simulating laser and radiation excitation and investigate carrier dynamics using non-adiabatic molecular dynamics. Our findings suggest that the relatively long radiative recombination process of carriers contributes to the slow RL decay time. [ABSTRACT FROM AUTHOR]

The photoluminescence and scintillation properties of KI:Eu synthesized by the vertical Bridgman-Stockbarger method were investigated. All the samples showed a broad peak at 430-450 nm under UV and X-ray irradiations, and the origin of emission was ascribed to the 4f65d1-4f7 transition of Eu2+. Furthermore, a tail emission at 500 nm under X-ray irradiation was observed, the origin of which could be ascribed to color centers associated with oxygen impurities. According to the pulse height spectra, the highest light yield (LY) under 241Am ?-ray (60 keV) irradiation was 3400 photons/MeV among the prepared samples. In terms of LY and afterglow, the optimal concentration of Eu was found to be 0.3%. [ABSTRACT FROM AUTHOR]

Eu:CaHfO3 single crystals with various Eu concentrations were synthesized by the floating zone method, and their photoluminescence (PL) and scintillation properties were investigated. All the samples showed PL peaks at 590, 620, and 650 nm, which were due to the 4f-4f transitions of Eu3+. The PL quantum yield of 1.0% Eu:CaHfO3 was the highest at 42.2% among the samples. The X-ray-induced scintillation spectra showed several emission peaks in the range of 400-690 nm, and the emissions were attributed to the 4f-4f transitions of Eu3+. Among the samples, 0.05% Eu:CaHfO3 showed the highest intensity. In the afterglow curves, the levels were within the range of 1,000-10,000 ppm and those of previous studies. [ABSTRACT FROM AUTHOR]

Ce-doped 20CsCl-20SrCl2-60ZnCl2 glasses were investigated for their optical and scintillation properties. Under X-ray irradiation, a broad emission peak at approximately 350 nm with a shoulder peak at 375 nm was observed, and its origin was attributed to Ce3+. In the pulse height spectrum under 241Am a-ray, the glass doped with 0.05% Ce exhibited the highest light yield (LY) of 25 ph/MeV (138 ph/5.5MeV-a) among zinc-halide-based glasses. The afterglow levels of the samples were superior to that of commercial CsI:Tl. [ABSTRACT FROM AUTHOR]

Eu-doped SrF² transparent ceramics were synthesized by spark plasma sintering, and their optical and scintillation properties were studied. The Eu-doped SrF² transparent ceramics showed an emission peak at 410 nm with excitations of 250 and 350 nm, and the PL quantum yield of the 0.1% Eu-doped SrF² transparent ceramic was 8.1%. Moreover, the Eu-doped SrF² transparent ceramics showed scintillation with emission peaks at 300 and 410 nm under X-ray irradiation. Based on the measured scintillation decay times, the origins of the emissions at 300 and 410 nm were self-trapped excitation and 5d-4f transitions of Eu2+ ions, respectively. The scintillation light yield of the 0.1% Eu-doped SrF² transparent ceramic was evaluated to be about 6100 photons/MeV under 137Cs γ-rays. [ABSTRACT FROM AUTHOR]

Tb-doped SrLu2O4 single crystals were grown by the floating zone method, and their optical and scintillation properties were evaluated. Regarding the scintillation properties, all the prepared crystals showed the sharp emission peaks assigned to Tb3+ 4f-4f transitions in the range of 350-650 nm. The obtained decay times of 1.0-1.6 ms were typical values for the Tb3+ 4f-4f transitions. From the results of the pulse area spectra, the 1.0% Tb-doped crystal showed the highest light yield of 19600 photons/MeV among the prepared crystals. [ABSTRACT FROM AUTHOR]

The photoluminescence (PL) and scintillation properties of Ce-doped BaHfO3 crystals were investigated. The Ce-doped BaHfO3 crystal is transparent and colorless after annealing treatment under a reduction condition. The broad luminescence band at ~370 nm was observed under ~280 nm excitation with the decay time of ~17 ns. The X-ray-induced scintillation spectra also showed the broad luminescence band at ~380 nm with a fast decay. The origin of the broad luminescence band at ~380 nm is attributed to the 5d-4f transition of Ce3+. The pulse height distribution under 137Cs gamma ray irradiation using Ce-doped BaHfO3 exhibited a distinguishable photoabsorption peak. The light yield of Ce-doped BaHfO3 is ~1600 photons/MeV. [ABSTRACT FROM AUTHOR]

The photoluminescence (PL), scintillation, and thermally stimulated luminescence (TSL) properties of Eu-doped (0.01, 0.1, and 1%) Al2O3 single crystals grown by the floating zone method were investigated systematically. The PL of the samples showed several sharp emission peaks across 550-750 nm originating from the 4f-4f transitions of Eu3+ and the 3d-3d transitions of Cr3+ impurity ions. The scintillation spectrum of the samples showed a broad emission peak at 320 nm due to the F+ center and an emission peak at 700 nm due to the 3d-3d transitions of Cr3+ impurity ions. All the samples showed TSL glow peaks at around 200, 320, and 375 °C. The TSL intensity of the 1% Eu-doped sample was the highest among the present three samples, and the TSL response was proportional to the irradiated X-ray dose in the range from 10 to 1000 mGy. The Eu-doped Al2O3 single crystal could be a novel candidate for personal dose monitoring applications. [ABSTRACT FROM AUTHOR]

We synthesized an undoped La2Be2O5 single crystal by the floating zone method and investigated its scintillation properties. The synthesized sample was confirmed to have a singlephase structure of La2Be2O5 as shown by the powder X-ray diffraction pattern. The diffuse transmittance spectrum of the synthesized sample had transmittance at 80% in the range of 250-850 nm. The scintillation spectrum had a broad emission band from 280 to 600 nm, which was derived from unidentified lattice defects. In the scintillation decay profile, the obtained decay time constants were 1.1, 6.2, and 386 ns. From pulse height spectra, the light yield of the La2Be2O5 single crystal was 1000 photons/MeV. In afterglow profiles, the afterglow level was 42.9 ppm. [ABSTRACT FROM AUTHOR]

The relationship between the lifetimes and emission wavelengths of scintillation and photoluminescence, when the initial excited state was the same, was studied. When the rate equation is dominant, lifetime should be the same at different emission wavelengths. However, we have observed the dependence of lifetime on emission wavelength in common scintillators. [ABSTRACT FROM AUTHOR]

Large‐sized transparent scintillators with a high photoluminescent quantum yield (PLQY) and self‐absorption‐free properties are highly desired to achieve high spatial resolution X‐ray imaging. In this research, a transparent 0D organic–inorganic (ETP)2SbCl5 (ETP = Ethyl triphenylphosphine) amorphous wafer is developed by melting the ETPCl and SbCl3 mixture and then undergoing a quenching process. The obtained amorphous wafer exhibits a high light transmittance of 86% in the range of 450–800 nm. It also shows a light emission peak at 624 nm, a Stokes shift of 259 nm, and PLQY approaching unity (99.3%). These properties enable it to produce X‐ray images with a high spatial resolution of 19.0 lp mm−1 at a modulation transfer function (MTF) value of 0.2, among the best values reported. Additionally, it also shows remarkable stability under continuous X‐ray illumination. Its unique optical properties and ability to be processed in large sizes make the organic–inorganic metal halide transparent wafer a promising scintillator. This also demonstrates the potential application of the melt‐quenching method in fabricating highly luminescent, low‐electronic‐dimensional metal halide wafers. [ABSTRACT FROM AUTHOR]

Fast and high‐linearity detection of fast neutron is vital for special nuclear material seeking, nuclear accident emergency response, nondestructive neutron imaging, and neutron cancer therapy. Neutron scintillators with fast time resolution and linear energy response are indispensable for precisely acquiring the energy and temporal evolution of fast neutron, but none of the conventional neutron scintillators, whether organic, two‐component or inorganic, have performed well in this regard. To address these challenges, it is urgent to develop novel neutron scintillators. Here, 2D hybrid perovskite single crystals (C4H12N)2PbBr4 (BA2PbBr4) successfully combined with fast response time of 2.66 ns and linear energy response to fast neutrons, γ ray, and α particle, is reported. The rapid response time and linear energy response of 2D hybrid perovskite scintillator originate from intensive states density of lead halide frameworks, which are the key fluorescence emitters under neutron irradiation. This effectively suppresses the ionization quenching effect during the fluorescence process. This work represents a milestone in fast neutron detection, demonstrating a new type of neutron scintillator based on 2D hybrid perovskite single crystals with fast and high‐linearity detection characteristics, having great potential in high precision neutron spectrum measurement and nuclear reaction kinetics monitoring. [ABSTRACT FROM AUTHOR]

This article details work performed on the synthesis and characterization of an inorganic mixed‐cation double halide perovskite, Cs2Ag.6Na.4In.85Bi.15Cl6 (CANIBIC). Single crystals have been created via a hydrothermal reaction, milled into a powder, and pressed into pellets, while nanocrystals have been directly synthesized via mechanosynthesis. A computational model is constructed to predict the X‐ray diffraction pattern of CANIBIC; this model aligns very well with the X‐ray diffraction pattern measured for CANIBIC crystal powder. This model can therefore be developed in the future as a tool to predict lattice parameters and crystal structures of other novel double‐halide perovskites. Photoluminescence spectra obtained from each format show broad emission centered at 630 nm, as is typical for self‐trapped exciton emission; self‐trapped exciton emission is also confirmed by investigating photoluminescence intensity as a function of laser power. Nanocomposites are produced via the loading of nanocrystals of CANIBIC into PMMA. Although nanocomposite disks consisting of a small proportion of CANIBIC nanocrystals in PMMA have a smaller mass attenuation coefficient than a pressed pellet of CANIBIC, these disks have comparatively bright radioluminescence due to their optical transparency. These nanocomposite disks are therefore a particularly useful format for the practical use of the CANIBIC scintillator. [ABSTRACT FROM AUTHOR]

Due to its short radiation length, moderate light output (8000‐9000 photons/MeV), high density (7.13 g cm−3), and non‐hygroscopicity, etc., Bi4Ge3O12 (BGO) material has been widely utilized as an advanced scintillator for irradiation detection. However, pure BGO cannot meet the requirements for future physics experiments and state‐of‐art industrial facilities coupled with a silicon photomultiplier (SiPM) due to its slow response time, poor radiation resistance, and excessive light output. Herein, a Ce‐doping strategy is reported for efficiently improving the overall performance (e.g., irradiation resistance, decay time, radioluminescence, and light output) of BGO that can be expectedly applied in future high energy physics detection. Ce‐doped BGO (BGO:Ce) displays higher radiation resistance ability under 10 h UV irradiation (97% of original) and a faster fluorescence lifetime (269 ns), superior to pure BGO. Furthermore, BGO:Ce shows ≈30% luminescence intensity of pure BGO, well eliminating the oversaturation of SiPM coupled with scintillation detectors. Theoretical calculations imply that an intense competition between electron or hole traps and Ce ions (Ce3+, Ce4+) can effectively reduce the concentration of color centers, thus enhancing irradiation resistance ability. [ABSTRACT FROM AUTHOR]

With the increasing demands of X‐ray detection and medical diagnosis, organic scintillators with intense and tunable X‐ray excited emission have been becoming important. To guarantee the X‐ray absorption, heavy atoms were widely added in reported organic scintillators, which led to emission quenching. In this work, we propose a new strategy to realize organic scintillators through the host‐guest doping strategy. Then the X‐ray absorption centers (host) and emission centers (guest) are separated. Under X‐ray excitation, these materials displayed intense and readily tunable emissions ranging from green (520 nm) to near infrared (NIR) regions (682 nm). Besides, the relationship between the X‐ray absorption and spatial arrangement of the heavy atoms in the host matrix was also revealed. The potential application of these wide‐range color tunable organic host‐guest scintillators in X‐ray imaging were demonstrated. This work provides a new feasible strategy for constructing high‐performance organic scintillators with tunable luminescence properties. [ABSTRACT FROM AUTHOR]

A single crystal of Zn2Te3O8 (ZTO) was grown using the conventional Czochralski technique. TGA analysis showed that the melting point of ZTO is 681 °C, while it exhibits a structural phase transition at 621 °C. The powder X-ray diffraction analysis of ZTO confirmed that it possesses a single crystalline monoclinic structure with the C2/c space group. An indirect band gap of 3.75 eV was estimated for the ZTO crystal based on its absorption spectrum. The X-ray-induced luminescence of the grown crystal comprised a broad band peaking at 565 nm, which can be tentatively assigned to the self-trapped exciton emission from the (Te3O8)4− molecular complexes. The photoluminescence measured under 280 nm excitation showed a broad band luminescence peaking at about 600 nm, and its intensity was significantly enhanced upon cooling the crystal from 300 K to 10 K. The photoluminescence decay time under 280 nm excitation was shown to have two exponential components in the range from 10 K to 175 K, which became a single exponential upon further heating the crystal. Low scintillation light was observed at room temperature both under α- and β-particle excitations from 241Am and 90Sr sources, respectively. The scintillation light yield measured under β-particle excitation from the 90Sr source was enhanced by about five orders of magnitude at 10 K in comparison to that at 300 K. The scintillation light yield measured at 10 K under the same experimental conditions for ZTO in comparison with the well-known cryogenic scintillator Li2MoO4 (LMO) was shown to have four times higher scintillation light. A single-crystal ingot of ZTO was obtained for the first time; however, it had several cracks due to its phase transition. Notably, scintillation at low temperatures for a Te-based crystal was observed for the first time. These preliminary findings are very promising and show that ZTO will be a good candidate for cryogenic phonon scintillation detectors for the 0νββ decay search of 130Te. [ABSTRACT FROM AUTHOR]

Na 3 V 2 (PO 4) 3 (NVP) has attracted much attention due to its excellent potential for sodium storage property. However, low electronic and ionic conductivities severely limit further development. Herein, a dimensional gradient structure of Ce/Mo co-doped and carbon nanotubes (CNTs) enwrapped Na 3 V 2 (PO 4) 3 /C–CeO 2 @CNTs system is constructed by a facile sol-gel method for the first time. The much larger Ce3+ can be used as the pillar ions to buffer the crystal deformation and enhance the structural stability. Moreover, the high charge and strong self-polarization ability of Ce can suppress the increase of charge transfer resistance during the charge/discharge process, which is beneficial to improve the electrochemical performance. Meanwhile, the doping of high-valent Mo6+ generates beneficial vacancies to elevate the Na + diffusion kinetics. The presence of encapsulated CNTs inhibits particle growth, optimizing particle size and shortening ion delivery paths. Significantly, a new conductive CeO 2 phase is clearly identified combining with carbon layers to construct favorable bilayer conductive networks, which effectively facilitate electronic transport. Thus, the modified Na 3 V 1.79 Ce 0.07 Mo 0.07 (PO 4) 3 /C@CNTs (CeMo0.07@CNTs) exhibits a reversible capacity of 110.3 mAh g−1 at 1C, with 91% retention after 1000 cycles. It releases a capacity of 74.9 mAh g−1 at 30C and maintains at 73.9 mAh g−1 after 12000 cycles with a high retention rate of 98.7%. Furthermore, a high retention rate of 83.2% can be obtained after cycling 15000 cycles at 80C, corresponding to a low decay rate of 0.0011% each cycle. In addition, the CHC//CeMo0.07@CNTs asymmetric full cell reveals high specific capacity of 91.59 mAh g−1, demonstrating its excellent practical prospects. [ABSTRACT FROM AUTHOR]

Lead perovskite nanocrystals (PNCs) have shown great potential for optoelectronic device applications due to their excellent optoelectronic properties. However, the application of PNCs is significantly limited due to the inferior stability resulting from the highly dynamic ligands on the surface. Herein, poly(maleic anhydride‐alt‐1‐octadecene) (PMAO) with low molecular weight (Mn = 1911) is synthesized by copolymerization and used as multi‐dentate ligands to prepare CsPbBr3 PNCs via hot injection. The PNCs exhibit excellent water resistance, which maintains fluorescence for 2600 min while conventional PNCs are completely destroyed after 100 min. Density functional theory calculations demonstrate that PMAO as a multi‐dentate ligand has higher adsorption energy to the surface of PNCs. Due to the large amount of extra anhydride structure of PMAO, PMAO‐PNCs are used as a cross‐linking agent to directly prepare flexible films by an in situ one‐step polymerization reaction with 1,3‐bis(3‐aminopropyl) polydimethylsiloxane (PDMS‐NH2). The fluorescent flexible films show great potential for applications including X‐ray imaging scintillators and flexible light‐emitting diodes (LEDs). This study can provide guidance to prepare ultra‐stable PNCs and flexible perovskite films with good stability in a simple and efficient way. [ABSTRACT FROM AUTHOR]

Background: Evaluation of the boron dose is essential for boron neutron capture therapy (BNCT). Nevertheless, a direct evaluation method for the boron‐dose distribution has not yet been established in the clinical BNCT field. To date, even in quality assurance (QA) measurements, the boron dose has been indirectly evaluated from the thermal neutron flux measured using the activation method with gold foil or wire and an assumed boron concentration in the QA procedure. Recently, we successfully conducted optical imaging of the boron‐dose distribution using a cooled charge‐coupled device (CCD) camera and a boron‐added liquid scintillator at the E‐3 port facility of the Kyoto University Research Reactor (KUR), which supplies an almost pure thermal neutron beam with very low gamma‐ray contamination. However, in a clinical accelerator‐based BNCT facility, there is a concern that the boron‐dose distribution may not be accurately extracted because the unwanted luminescence intensity, which is irrelevant to the boron dose is expected to increase owing to the contamination of fast neutrons and gamma rays. Purpose: The purpose of this research was to study the validity of a newly proposed method using a boron‐added liquid scintillator and a cooled CCD camera to directly observe the boron‐dose distribution in a clinical accelerator‐based BNCT field. Method: A liquid scintillator phantom with 10B was prepared by filling a small quartz glass container with a commercial liquid scintillator and boron‐containing material (trimethyl borate); its natural boron concentration was 1 wt%. Luminescence images of the boron‐neutron capture reaction were obtained in a water tank at several different depths using a CCD camera. The contribution of background luminescence, mainly due to gamma rays, was removed by subtracting the luminescence images obtained using another sole liquid scintillator phantom (natural boron concentration of 0 wt%) at each corresponding depth, and a depth profile of the boron dose with several discrete points was obtained. The obtained depth profile was compared with that of calculated boron dose, and those of thermal neutron flux which were experimentally measured or calculated using a Monte Carlo code. Results: The depth profile evaluated from the subtracted images indicated reasonable agreement with the calculated boron‐dose profile and thermal neutron flux profiles, except for the shallow region. This discrepancy is thought to be due to the contribution of light reflected from the tank wall. The simulation results also demonstrated that the thermal neutron flux would be severely perturbed by the 10B‐containing phantom if a relatively larger container was used to evaluate a wide range of boron‐dose distributions in a single shot. This indicates a trade‐off between the luminescence intensity of the 10B‐added phantom and its perturbation effect on the thermal neutron flux. Conclusions: Although a partial discrepancy was observed, the validity of the newly proposed boron‐dose evaluation method using liquid‐scintillator phantoms with and without 10B was experimentally confirmed in the neutron field of an accelerator‐based clinical BNCT facility. However, this study has some limitations, including the trade‐off problem stated above. Therefore, further studies are required to address these limitations. [ABSTRACT FROM AUTHOR]

Copper‐based halides have emerged as promising scintillator materials for X‐ray imaging due to their favorable photophysical characteristics, such as negligible self‐absorption, high light output, and fast decay. Among these materials, Cs3Cu2I5, a blue emitter, currently delivers the highest scintillation light output under steady‐state X‐rays. However, there is a significant spectral mismatch between its emission band and the spectral responsivity of regular flat‐panel photodiode arrays. In this study, a comprehensive analysis of the physical properties of the CsCu2I3 scintillator is conducted, and its perfect spectral compatibility is discovered, which results in a higher photodiode signal despite its relatively lower light output compared to typical Cs3Cu2I5 scintillators. Furthermore, CsCu2I3 exhibits faster light decay properties, making it especially suitable for Computed Tomography (CT) X‐ray imaging. High‐quality X‐ray cone beam computed tomography (CBCT) imaging is successfully demonstrated using the fast‐decaying CsCu2I3 scintillator screen. Additionally, the flexibility of the scintillator allows for non‐planar imaging, showcasing advantages not available with traditional rigid scintillators. These results not only highlight the significant promise of the CsCu2I3 scintillator but also emphasize the necessity of considering spectral compatibility when designing novel scintillator materials. [ABSTRACT FROM AUTHOR]

Conventional scintillator‐based X‐ray imaging typically captures the full spectral of X‐ray photons without distinguishing their energy. However, the absence of X‐ray spectral information often results in insufficient image contrast, particularly for substances possessing similar atomic numbers and densities. In this study, an innovative multi‐energy X‐ray linear‐array detector is presented that leverages side‐illuminated X‐ray scintillation using the emerging metal halide Cs3Cu2I5. The negligible self‐absorption characteristic not only improves the scintillation output but is also beneficial for improving the energy resolution for the side‐illuminated scintillation scenarios. By exploiting Beer's law, which governs the absorption of X‐ray photons with different energies, the incident X‐ray spectral can be reconstructed by analyzing the distribution of scintillation intensity when the scintillator is illuminated from the side. The relative error between the reconstructed and measured X‐ray spectral is < 5.63%. This method offers an additional energy‐resolving capability for X‐ray linear‐array detectors commonly used in computed tomography (CT) imaging setups, surpassing the capabilities of conventional energy‐integration approaches, all without requiring extra hardware components. A proof‐of‐concept multi‐energy CT imaging system featuring eight energy channels is successfully implemented. This study presents a simple and efficient strategy for achieving multi‐energy X‐ray detection and CT imaging based on emerging metal halides. [ABSTRACT FROM AUTHOR]

As a part of radiation emergency response, a rapid method for estimation of gross-α and gross-β activities in urine samples using liquid scintillation counting technique was standardized and validated using spiked urine samples. Effect of various storage conditions such as temperature, storage time and use of preservatives on estimation of gross-α and gross-β activities was investigated systematically. Measurement results revealed that urine samples either should be stored at lower temperatures (≤ 5 °C) or should be acidified with 1% v/v HCl for quantification of gross-α and gross-β activities with bias ≤ 10%. [ABSTRACT FROM AUTHOR]

Core to advancing time‐of‐flight positron emission tomography (ToF‐PET) toward a less invasive, more flexible procedure with a higher diagnostic power is the development of enhanced radiation detector materials. One promising avenue is the development of heterostructured scintillators where multiple materials work in synergy to exceed the performance of each individual component. Applied to ToF‐PET detectors, one component contributes predominantly to the absorption of gamma rays and the other to the creation of ultra‐fast photons. Whilst other authors have proposed various concepts, heterostructured scintillators are still in their infancy and scientifically guiding their development remains a challenge. Toward this aim and based on simulation and modeling developments, heterostructure properties are directly linked to ToF‐PET performance. This is made possible by redefining the notions of detector photo‐peak efficiency and timing response, as defined for monolithic detectors, in the context of heterostructured scintillators. Their overall potential is then discussed as a function of the materials and design used. This provides a quantitative framework to rapidly and efficiently support the advancement of heterostructured detectors for ToF‐PET technology. [ABSTRACT FROM AUTHOR]

Rare-event search experiments located on-surface, such as short-baseline reactor neutrino experiments, are often limited by muon-induced background events. Highly efficient muon vetos are essential to reduce the detector background and to reach the sensitivity goals. We demonstrate the feasibility of deploying organic plastic scintillators at sub-Kelvin temperatures. For the NUCLEUS experiment, we developed a cryogenic muon veto equipped with wavelength shifting fibers and a silicon photo multiplier operating inside a dilution refrigerator. The achievable compactness of cryostat-internal integration is a key factor in keeping the muon rate to a minimum while maximizing coverage. The thermal and light output properties of a plastic scintillation detector were examined. We report first data on the thermal conductivity and heat capacity of the polystyrene-based scintillator UPS-923A over a wide range of temperatures extending below one Kelvin. The light output was measured down to 0.8 K and observed to increase by a factor of 1.61 ± 0.05 compared to 300 K. The development of an organic plastic scintillation muon veto operating in sub-Kelvin temperature environments opens new perspectives for rare-event searches with cryogenic detectors at sites lacking substantial overburden. [ABSTRACT FROM AUTHOR]