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The zero-dimensional copper halide perovskite Cs 3 Cu 2 I 5 displays extraordinary luminescence and scintillation characteristics, and high-quality crystals are extremely desirable for exploring the commercial applications. Currently, the most critical issue in the solution growth of Cs 3 Cu 2 I 5 crystals is the easy oxidation of halides, which significantly hinders the optimization of crystal qualities. The hypophosphorous acid (H 3 PO 2) has been applied to inhibit the oxidation, nevertheless, the related mechanism is elusive and has been largely ignored. Herein, Cs 3 Cu 2 I 5 crystals have been grown from N, N-Dimethylformamide (DMF) solvent by the antisolvent vapor-assisted crystallization (AVC) method. It is verified that H 3 PO 2 effectively prevents the oxidation of Cs 3 Cu 2 I 5 by rapidly reducing Cu2+ and I 3 −, maintaining the stability of the precursor solution and continuously suppressing oxidation during the whole growth process. Meanwhile, by increasing the acidity of the solution, H 3 PO 2 dissolve precursor colloids and efficiently enhance the solubility of halides. Thus, the addition of H 3 PO 2 favors the rapid growth of centimeter-sized Cs 3 Cu 2 I 5 crystals with well-defined crystallographic planes within several days. As excellent gamma ray scintillator, the crystal exhibits high light yield of 38000 photons/MeV, with energy resolution of 5.6 % under 662 keV radiation from a 137Cs source. This work deeply elucidates new insight into the critical effect of H 3 PO 2 in the DMF based solution crystal growth, facilitating the preparation of large-size and high-performance copper halide perovskite crystals. [ABSTRACT FROM AUTHOR]

Silicon photomultipliers (SiPMs) are solid-state single-photon-sensitive detectors that show excellent performance in a wide range of applications. In FBK (Trento, Italy), we developed a position-sensitive SiPM technology, called "linearly graded" (LG-SiPM), which is based on an avalanche-current weighted-partitioning approach. It shows position reconstruction resolution below 250 μm on an 8 × 8 mm2 device area with four readout channels and minimal distortions. A recent development in terms of LG-SIPM is a larger chip version (10 × 10 mm2) based on FBK NUV-HD technology (near-ultraviolet sensitive), with a peak photon detection efficiency at 420 nm. Such a large-area detector with position sensitivity is very interesting in applications like MR-compatible PET, high-energy physics experiments, and readout of time-projection chambers, gamma and beta cameras, or scintillating fibers, with a reduced number of channels. These SiPMs were characterized in terms of noise, photon detection efficiency, and position resolution. We also developed tiles of 2 × 2 and 3 × 3 LG-SiPMs, reaching very large sensitive areas of 20 × 20 mm2 and 30 × 30 mm2. We implemented a "smart-channel" configuration, which allowed us to have just six output channels for the 2 × 2 elements and eight channels for the 3 × 3 element tiles, preserving a position resolution below 0.5 mm. These kinds of detectors provide a great advantage in compact and low-power applications by maintaining position sensitivity over large areas with a small number of channels. [ABSTRACT FROM AUTHOR]

This research investigates the fabrication and analysis of plastic scintillators using an epoxy matrix. Plastic scintillators are widely used in radiation detection because of their low cost, ease of fabrication, resistance to moisture, and rapid decay time. The production process involved dissolving primary and secondary dopants, p-terphenyl (p-TP) and 1,4-bis [2-(phenyloxazolyl)]-benzene (POPOP), respectively, into a low-viscosity of cycloaliphatic amine as hardener B, which was then combined with Bisphenol-A diglycidyl ether as epoxy A. The ratio of primary and secondary dopants was varied in the experiment. The resulting scintillators were characterized using Fourier Transform Infrared Spectroscopy (FTIR) to analyze the functional groups that constitute the epoxy before and after curing. The morphology of the scintillator sample was evaluated using SEM and The thermal properties were evaluated with differential scanning calorimetry (DSC). The optical properties of the scintillator were studied using a UV-Vis Spectrophotometer and a Fluorescence Spectrophotometer. The performance of the scintillator in detecting gamma rays was evaluated using a module comprising a Photomultiplier Tube (PMT) and a Multichannel Analyzer (MCA) with sources of gamma Cesium 137. The results showed that epoxy-based scintillators can provide a detective response to gamma rays. This study demonstrates the potential of epoxy-based plastic scintillators for use in radiation detection. [ABSTRACT FROM AUTHOR]

The reduction in the effective dose of evacuated injured persons through contaminated areas of nuclear accidents is an essential emergency services requirement. In this context, there appeared a need to develop a dose-optimised route finding method for firefighting rescue vehicles, which includes the development of a real-time decision support measurement and evaluation system. This determines and visualises the radiation exposure of possible routes in a tested area. The system inside and outside of the vehicle measures the ambient dose equivalent rate, the gamma spectra, and also the airborne radioactive aerosol and iodine levels. The method uses gamma radiation measuring NaI(Tl) scintillation detectors mounted on the outside of the vehicle, to determine the dose rate inside the vehicle using the previously recorded attenuation conversation function, while continuously collecting the air through a filter and using an alpha, beta, and gamma radiation measuring NaI(Tl)+ PVT + ZnS(Ag) scintillator to determine the activity concentration in the air, using these measured values to determine the effective dose for all routes and all kinds of vehicles. The energy-dependent shielding effect of the vehicle, the filtering efficiency of the collective protection equipment, and the vehicle's speed and travel time were taken into account. The results were validated by using gamma point sources with different activity and energy levels. The measurement results under real conditions and available real accident data used in our simulations for three different vehicles and pedestrians proved the applicability of the system. During a nuclear accident based on our model calculations, the inhalation of radioactive aerosols causes a dose almost an order of magnitude higher than the external gamma radiation caused by the fallout contamination. The selection of the appropriate vehicle and its route is determined by the spectrum that can be measured at the accident site but especially by the radioactive aerosol concentration in the air that can be measured in the area. In the case of radiation measuring detectors, the shielding effect of the carrier vehicle must be taken into account, especially in the case of heavy shielding vehicles. The method provides an excellent opportunity to reduce the damage to the health of accident victims and first responders during rescue operations. [ABSTRACT FROM AUTHOR]

In this study, the interaction parameters of neutrons, charge particles and gamma rays in seven inorganic scintillation materials with densities ranged from 3.86 to 8.30 g/cm3 were theoretically examined. SRIM Monte Carlo software was used to determine the range of $ {H^ + },H{e^{ + + }},A{u^ + }and\textrm{ }\,{O^{ - - }} $ H + , H e + + , A u + and O − − ions in the energy range (0.01–20) MeV, Phy-X/PSD while Py-MLBUF computer programs were used to estimate gamma radiation interaction parameters in the energy range (0.02–15) MeV. The electron total stopping power and range values at energies ranging from 0.01 to 1000 MeV were calculated using the ESTAR NIST program. The fast neutron removal cross-section (FNRCS) and the macroscopic effective removal cross-section (MRCS) were calculated using the Phy-X/PSD and MRCS tools, respectively. The outcomes of this research showed that the range of $ {H^ + },H{e^{ + + }},A{u^ + }and\textrm{ }\,{O^{ - - }} $ H + , H e + + , A u + and O − − ions increased with decreasing sample density but decreased with increasing projectile energies; the largest range of $ {H^ + } $ H + is 2090 µm in the lowest density S1 sample, while the range of $ \textrm{ }A{u^ + } $ A u + is 5.16 µm in the same sample. The denser sample S7 had the highest stopping power and the lowest range at higher electron energies. The S1 sample had the highest calculated HVL value of 5.403 cm, while the S7 sample had the lowest calculated HVL value of 0.0008 cm. Rising sample density causes the MAC to rise, while rising gamma energy causes the MAC to decrease. The highest MAC value recorded was 107 cm2/g at 0.015 MeV in the S7 sample, and the lowest value recorded was 0.0369 cm2/g at 15 MeV in the S1 sample. For all inorganic scintillation samples at particular gamma energies, the standard deviations for the MAC, HVL and Zeff values between the Phy-X/PSD and, Py-MLBUF programs were calculated. With energy range variation, the results for Zeff for the two samples S2 and S4 appeared to be constant. Regards to the fast neutrons, the heights value's of FNRCS, and MRCS were recorded for S7. [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]

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]

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]

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]

In this paper, the details of the development and performance characterisation of a compact, low-power gamma spectrometer for environmental gamma radiation monitoring networks are presented. To reduce the power consumption and the size of the spectrometer, a gamma detector comprising a silicon photomultiplier coupled to a Gd3Ga3Al2O12:Ce,B (GGAG:Ce,B) scintillator has been used for gamma spectrometry. Initially, a Monte Carlo simulation study was carried out to verify the suitability of the 5 mm × 5 mm × 5 mm GGAG:Ce,B crystal for spectrometry of gamma sources in the energy range 60–1332 keV. For minimising the power consumption, the signal processing electronics has been custom designed. This electronics was realised using standard off-the-shelf components to reduce the cost. The developed spectrometer is of size 16 cm × 10 cm × 6 cm, weighs 600 g and consumes 600 mW power. The spectrometer is developed such that it could be directly interfaced with GSM/Xbee for wireless communication with the radiation monitoring networks. The lower-level discriminator threshold of the system is 40 keV and the total electronic noise is <20 keV. The experimentally measured sensitivity of the spectrometer for 137Cs (662 keV) is 2.4 cps/μGy/h at 3.5 V overvoltage. The spectrometer offers excellent linearity over the measured energy range of 60–1332 keV and an energy resolution of ~10% for 662 keV gamma-ray at room temperature. [ABSTRACT FROM AUTHOR]

Background: Pulsed reduced dose rate (PRDR) is an emerging radiotherapy technique for recurrent diseases. It is pertinent that the linac beam characteristics are evaluated for PRDR dose rates and a suitable dosimeter is employed for IMRT QA. Purpose: This study sought to investigate the pulse characteristics of a 6 MV photon beam during PRDR irradiations on a commercial linac. The feasibility of using EBT3 radiochromic film for use in IMRT QA was also investigated by comparing its response to a commercial diode array phantom. Methods: A plastic scintillator detector was employed to measure the photon pulse characteristics across nominal repetition rates (NRRs) in the 5–600 MU/min range. Film was irradiated with dose rates in the 0.033–4 Gy/min range to study the dose rate dependence. Five clinical PRDR treatment plans were selected for IMRT QA with the Delta4 phantom and EBT3 film sheets. The planned and measured dose were compared using gamma analysis with a criterion of 3%/3 mm. EBT3 film QA was performed using a cumulative technique and a weighting factor technique. Results: Negligible differences were observed in the pulse width and height data between the investigated NRRs. The pulse width was measured to be 3.15 ± 0.01 μs$\mu s$ and the PRF was calculated to be 3–357 Hz for the 5–600 MU/min NRRs. The EBT3 film was found to be dose rate independent within 3%. The gamma pass rates (GPRs) were above 99% and 90% for the Delta4 phantom and the EBT3 film using the cumulative QA method, respectively. GPRs as low as 80% were noted for the weighting factor EBT3 QA method. Conclusions: Altering the NRRs changes the mean dose rate while the instantaneous dose rate remains constant. The EBT3 film was found to be suitable for PRDR dosimetry and IMRT QA with minimal dose rate dependence. [ABSTRACT FROM AUTHOR]

In this paper, we present XStorm, a gamma ray spectrometer developed to detect gamma ray glows and terrestrial gamma ray flashes (TGFs) in close proximity. Measurements are mostly planned to take place on balloon campaigns but also on the ground using bigger detectors. The main aim in developing XStorm is to perform new in situ and close proximity measurements of those events to improve the understanding of the physical processes involved. For that, we ensured XStorm reached performances adapted to glow and TGF detections. It detects photons with energy between ∼400 keV and ∼20 MeV. Detected particles are timetagged with a 600 ns precision with respect to UTC. Using two types of scintillator, Bismuth Germanium Oxide and EJ‐276 plastic associated with SiPMs, the instrument is able to discriminate three types of particles involved in those events: photons, neutrons, and electrons. The behavior of the detector under high particle fluxes has been quantified through ground testing using a pulse generator. A triggered detection system has been developed, with different thresholds depending on the target of study. First measurements have been carried out with test flights in fair weather conditions and are presented here. Estimations of the configurations in which a gamma ray glow can be detected by XStorm and of the number of TGFs that could be detected in specific campaigns are also addressed. Plain Language Summary: Terrestrial gamma ray flashes (TGFs) are bursts of high‐energy photons generated in thunderstorms in less than 100 μs, whereas gamma ray glows are enhancement of the high‐energy radiation background in thunderstorms, lasting from seconds to minutes. We present a gamma ray spectrometer, XStorm, designed to detect terrestrial gamma ray flashes (TGFs) and gamma ray glows in close proximity. It is composed of two scintillators of different kinds to allow the detection of TGF and gamma ray glow photons (energies between 400 keV and 20 MeV, with a time precision of 600 ns UTC). XStorm measurements are mainly planned to take place on board balloons, but can also be performed at ground level using bigger scintillators. XStorm is able to discriminate photons, electrons and neutrons, that are particle types involved in TGFs. We show the first measurements in fair weather and configurations allowing the detection of gamma ray glows. We estimate that XStorm will detect ∼0.5 TGF on average over one balloon flight of Stratéole‐2 campaign presented in the scientific objectives. Key Points: Development of a gamma ray spectrometer to detect gamma ray glows and terrestrial gamma ray flashes (TGFs), able to discriminate photons, electrons, and neutronsResults from balloon test flights performed in fair weather conditions, detecting the background radiation level as a function of altitudeEstimation of the detectability of gamma ray glows and TGFs as a function of altitude with XStorm [ABSTRACT FROM AUTHOR]

POLAR-2, a plastic scintillator based Compton polarimeter, is currently under development and planned for a launch to the China Space Station in 2025. It is intended to shed a new light on our understanding of Gamma-Ray Bursts by performing high precision polarization measurements of their prompt emission. The instrument will be orbiting at an average altitude of 383 km with an inclination of 42° and will be subject to background radiation from cosmic rays and solar events. In this work, we tested the performance of plastic scintillation bars, EJ-200 and EJ-248M from Eljen Technology, under space-like conditions, that were chosen as possible candidates for POLAR-2. Both scintillator types were irradiated with 58 MeV protons at several doses from 1.89 Gy(corresponding to about 13 years in space for POLAR-2) up to 18.7 Gy, that goes far beyond the expected POLAR-2 life time. Their respective properties, expressed in terms of light yield, emission and absorption spectra, and activation analysis due to proton irradiation are discussed. Scintillators activation analyses showed a dominant contribution of β + decay with a typical for this process gamma-ray energy line of 511 keV. [ABSTRACT FROM AUTHOR]

Nano-glasses are next-generation scintillators combining favorably the merits of both scintillator crystals and glasses. Here, a new nano-glass scintillator is prepared embedding CsGd 2 F 7 :Ce3+ nanocrystals (NCs). The microscopic morphology, particle size, and distribution of the NCs are studied by high resolution transmission electron microscopy. Significantly enhanced radioluminescence efficiency is obtained in the nano-glasses. The largest integrable intensity of X-ray excited luminescence is 316% of the standard Bi 4 Ge 3 O 12 (BGO) crystal. A well-resolved full-energy peak with an energy resolution of 17.4% is registered for the 662 keV gamma rays, and the light yield is determined to be 827 ± 8 ph/MeV. The nano-glass scintillators exhibit good radiation hardness and thermal stability. As a proof of concept, an X-ray imaging system of a good resolution is built on the nano-glass scintillators. [ABSTRACT FROM AUTHOR]

The research aims to study the primary interaction between gamma radiation in CeBr3 crystal. The analysis of mass attenuation coefficient (MAC), effective atomic number (Zeff), electron density (Neff), mean free path (MFP), and energy absorption buildup factor (EABF) was evaluated using the using the WinXCom software. Also, the interaction with charged particles as the total mass stopping power (TMSP), projected range (PR) of proton ( H 1 1 ) and alpha ( H 2 4 e ) particles were evaluated by SRIM programming. The results found that the MAC depends on the energy ranges, the photoelectric effect is the main interaction at low energy ranges, Compton scattering phenomena illustrate and evidents at intermediate energy ranges, and pair production characteristics dominate over on 1.022 MeV in high energy ranges. Moreover, absorption edges appear on energy's discontinuity at low energy. The Zeff and Neff show similar trends and correspond to the energy ranges. The MFP of the CeBr3 compared with some standard scintillators such as NaI and BGO crystal and found that the BGO responds to faster interaction than CeBr3 and NaI crystals. The EABF shows scattering energies followed by atomic equivalent (Zeq), and they also increase with increasing penetration depth (mfp). The TMSP and PR depend on charged particles, density, and the unit path distance of a material. [ABSTRACT FROM AUTHOR]

Currently, the most used methods of plastic scintillator (PS) manufacturing are cell casting and bulk polymerisation, extrusion, injection molding, whereas digital light processing (DLP) 3D printing technique has been recently introduced. For our research, we measured blue-emitting EJ-200, EJ-208, green-emitting EJ-260, EJ-262 cell cast and two types of blue-emitting DLP-printed PSs. The light output of the samples, with the same dimension of 10 mm × 10 mm × 10 mm, was compared. The light output of the samples, relative to the reference EJ-200 cell-cast scintillator, equals about 40–49 and 70–73% for two types of 3D-printed, and two green-emitting cell-casted PSs, respectively. Performance of the investigated scintillators is sufficient to use them in a plastic scintillation dosemeter operating in high fluence gamma radiation fields. [ABSTRACT FROM AUTHOR]

The problem of boron concentration monitoring during the boron neutron capture therapy (BNCT) therapy is one of the main challenges of this type of radiotherapy and is directly related to the nature of the interaction of neutrons with mater. Among the available in vivo methods of boron monitoring positron emission tomography seems to be very promising but it requires a new boron carrier with a β+ emitter, which is not yet clinically available. An alternative solution may be the prompt gamma radiation analysis (PGRA) based on the secondary radiation emitted in the interaction of neutrons with the patient's tissues. This method requires, however, compact gamma radiation detection systems sustaining high counting rates and characterized by very good energy resolution. In this contribution, we present state-of-the-art solutions for monitoring in BNCT based on PGRA. Moreover, we describe a new concept of such a system based on position-sensitive scintillator detectors equipped with an anti-Compton shield and data analysis supported with modern artificial intelligence algorithms. [ABSTRACT FROM AUTHOR]

Organic liquid scintillation detectors are widely used to measure the presence of radiation. With these devices, there are advantages in that they are easy to manufacture, large in size, and have a short fluorescence decay time. However, they are not suitable for gamma spectroscopy because they are composed of a low-atomic-number material. In this regard, alternative materials for the secondary solute used in basic organic liquid scintillators have been investigated, and the applicability of alternative materials, the detection characteristics, and neutron/gamma identification tests were all assessed. 7-Diethylamino-4-methylcoumarin (DMC), selected as an alternative material, is a benzopyrone derivative in the form of colorless crystals with high fluorescence, a high quantum yield in the visible region, and excellent light stability. In addition, it has a large Stokes shift, and solubility in a solvent is good. Through an analysis in this study, it was found that the absorption wavelength range of DMC coincides with the emission wavelength range of PPO, which is the primary solute used with DMC. Finally, it was confirmed that the optimal concentration of DMC was 0.08 wt%. As a result of performing gamma and neutron measurement tests using a DMC-based liquid scintillator, it was found to perform well (FOM = 1.42) compared to a commercial liquid scintillator, BC-501A. [ABSTRACT FROM AUTHOR]

Organic–inorganic composite scintillators, demonstrating advantages of easy large-area preparation and a high detection efficiency, have shown enormous potential application prospects in radiation detection and imaging. In this study, bulk polystyrene (PS) composite scintillators were successfully prepared by embedding inorganic BaF2 particles with a loading amount of up to 80 wt% during the polymerization process of the plastic scintillator. The inorganic BaF2 particles were uniformly dispersed in the organic matrix. With the increase of the loading amounts of BaF2 particles, the X-ray-excited luminescence intensity of the PS-BaF2 composite scintillators was about eight times higher than that of the commercial pure plastic scintillator. The scintillation counts under the gamma ray (59.5 KeV) irradiation also showed that the detection efficiency was obviously enhanced by BaF2 particle loading. More importantly, their scintillation pulse retains the decay kinetics of the organic matrix without loading the slow-decay component of BaF2. This work provides a promising solution for the application of the PS-BaF2 composite scintillator in high-efficiency radiation detection and large-area imaging. [ABSTRACT FROM AUTHOR]

Zero‐dimensional (0D) structure‐based manganese metal halides (MHs) are believed to be the most promising candidates for the next‐generation X‐ray scintillators due to their intense radioluminescence and environmental friendliness. However, low‐temperature (<180 °C), large‐area integration with more efficient X‐ray detection remains a tremendous challenge. Herein, from the perspective of cation (ionic liquids) structure design, the basic physical parameters of 0D MHs are regulated. And the calculations and experimental results demonstrate larger‐size cations that induce lower melting temperatures, larger exciton‐binding energies, larger ion migration energy, and tunable hardness, which are most desirable for MHscintillators. As a result, the champion materialHTP2MnBr4is achieved as glassy transparency wafer by low‐temperature (165 °C) melt‐quenching. Its application to X‐ray imaging features high spatial resolution (17.28 lp mm−1), scalability (>30 × 30 cm2), and integration with strong coupling force. Furthermore, HTP2MnBr4 glass with reproducible properties demonstrates a high light yield (38 000 photon MeV−1), excellent irradiation stability, and low detection limit (0.13 µGy s−1). The authors believe this work will provide guidance for MHscintillators to further commercial applications. [ABSTRACT FROM AUTHOR]

Barium fluoride, an inorganic scintillation material used for the detection of X-ray and/or gamma-ray radiation, has been receiving increasing attention in the field of radiation measurements in fast-timing applications. To make full use of its timing properties, its slow emission around the ultraviolet region, more specifically, the 300 nm region needs to be suppressed. Although doping ions, such as lanthanum, yttrium, and cadmium, can suppress the slow component, such techniques can lose information of interacted radiations. Consequently, a suppression technique that does not suffer from information loss while maintaining precise timing measurements would be desirable. In this study, we proposed aluminum nano-disk-based plasmonic filters to suppress slow emissions while maintaining fast emissions around 195 and 220 nm and a usability of the slow component. Finite-difference time-domain simulations and experimental results exhibited good agreement, with over 90% of slow components being adequately suppressed without sacrificing fast components, proving that aluminum nanodisks can be used for ultraviolet filters. Moreover, based on the designed filter performance, we conducted coincidence time resolution simulations for positron–electron annihilation gamma rays from an analytical perspective. The simulations indicated the designed filters could maintain high timing performance. Consequently, the proposed plasmonic ultraviolet filter was suitable for maximizing the potential of barium fluoride scintillators. [ABSTRACT FROM AUTHOR]

Scintillators have long been known as radiation detectors and are still used in various applications. Recently, scintillators containing 6Li have been developed as neutron detectors and have attracted attention. 6Li absorbs thermal neutrons and emits α+3H, which is promising as a neutron detector if it can be separated from background gamma rays. We have been developing Eu:LiI–CaI2-based scintillators (Eu:LiCaI) for this purpose. In scintillator detectors, waveform information is generally used to distinguish particles such as neutrons and gamma rays. We propose a new particle identification method using emission wavelength information. In this study, experiments were conducted using Eu:LiCaI crystals, multi-pixel photon counter optical sensors, and long-wavelength cut filters to verify the proposed method. The results of irradiating a 252Cf neutron source and a 60Co gamma-ray source indicate that there is a particle dependence on the output signal ratio with and without filters. This indicates that different types of radiation particles have different emission wavelengths. This is the first demonstration of a wavelength-based particle identification method. [ABSTRACT FROM AUTHOR]

Background: In this research, the response of a 10 × 10 × 10 mm3 commercially available PbF2 crystal was experimentally assessed under X-ray and gamma ray radiation to verify the possible application of this material in X-ray medical imaging. Methods: The measurements were performed under X-ray from 50 to 130 kVp and gamma ray excitation (Tc-99m 140 keV and I-131 365 keV). The PbF2 response was experimentally assessed by the determination of the absolute luminescence efficiency (AE), X-ray luminescence efficiency (XLE), and the stopping power of this scintillating crystal in terms of the energy absorption efficiency (EAE). The results were compared with bismuth germanate (BGO) crystal, which is commonly used in medical imaging modalities. Results: The AE of PbF2 gradually decreased from 50 kVp up to 130 kVp. The maximum value was 0.61 efficiency units (EU) at 140 keV, and the minimum value was 0.03 EU at 71 keV (130 kVp). Similarly, low values appeared for the XLE, where the maximum value was 16.9 × 10−5 at 140 keV. Conclusions: These findings show that the PbF2 scintillator has unacceptably low luminescence efficiency. Although PbF2 can effectively absorb radiation, the scintillation light, at room temperatures, is negligible, and, thus, it could not be used in medical imaging applications in the examined energy range. [ABSTRACT FROM AUTHOR]

Single-crystalline films (SCFs) of the LuAG: Ce garnet grown using the liquid-phase epitaxy method onto YAG single-crystal (SC) substrates were investigated for possible applications as composite thermoluminescent (TL) detectors. Such detectors may help to register the different components of ionizing radiation fields with various penetration depths, e.g., heavy charged particles and gamma or beta rays. It was found that the TL signal of LuAG: Ce SCF sufficiently differs from that of the YAG substrate concerning both the temperature and wavelength of emissions. Furthermore, even by analyzing TL glow curves, it was possible to distinguish the difference between weakly and deeply penetrating types of radiation. Within a test involving the exposure of detectors with the mixed alpha/beta radiations, the doses of both components were determined with an accuracy of a few percent. [ABSTRACT FROM AUTHOR]

A new broad-energy, high-resolution gamma ray spectrometer (GRS) with Compton suppression function has been developed recently in the HL-2A tokamak to obtain the gamma ray information in the energy range of 0.1–10 MeV. This is the first time to develop an anti-Compton GRS for a magnetic confinement fusion device. The anticoincidence detector consists of a large-volume high purity germanium (HPGe) crystal (Φ63 × 63 mm2) as the primary detector and eight trapezoidal bismuth germinate (BGO) scintillators (trapezoid crystal with 30 mm thickness) as the secondary detector. The anti-coincidence data processing is implemented by a digital-based data acquisition system with fast digitization and software signal processing technology. Using radioisotope gamma ray sources and Monte Carlo N-Particle code, the energy and efficiency of the spectrometer have been calibrated and quantitatively tested. The Compton continuum suppression factor reaches 4.2, and the energy resolution (Full Width at Half Maximum) of the 1.332 MeV full energy peak for 60Co is 2.1 keV. Measurements of gamma ray spectra with Compton suppression using the spectrometer have been successfully performed during HL-2A discharges with different conditions. The performance of the spectrometer and the first experimental results are presented in this paper. [ABSTRACT FROM AUTHOR]

The crystals of (Lu,Gd)3(Ga,Al)5O12 multicomponent garnets with high density ρ and effective atomic number Zeff are characterized by high scintillation efficiency and a light yield value up to 50,000 ph/MeV. During recent years, single-crystalline films and composite film/crystal scintillators were developed on the basis of these multicomponent garnets. These film/crystal composites are potentially applicable for particle identification by pulse shape discrimination due to the fact that α-particles excite only the film response, γ-radiation excites only the substrate response, and β-particles excite both to some extent. Here, we present new results regarding scintillating properties of selected (Lu,Gd)3(Ga,Al)5O12:Ce single-crystalline films under excitation by alpha and beta particles and gamma ray photons. We conclude that some of studied compositions are indeed suitable for testing in the proposed application, most notably Lu1.5Gd1.5Al3Ga2O12:Ce film on the GAGG:Ce substrate, exhibiting an α-particle-excited light yield of 1790–2720 ph/MeV and significantly different decay curves excited by α- and γ-radiation. [ABSTRACT FROM AUTHOR]

In nuclear power plants, particle accelerators, and other nuclear facilities, measuring the level of ionising gamma radiation is critical for the safety and management of the operation and the environment's protection. However, in many cases, it is impossible to monitor ionising radiation directly at the required location continuously. This is typically either due to the lack of space to accommodate the entire dosimeter or in environments with high ionising radiation activity, electromagnetic radiation, and temperature, which significantly shorten electronics' lifetime. To allow for radiation measurement in such scenarios, we designed a fibre optic dosimeter that introduces an optical fibre link to deliver the scintillation radiation between the ionising radiation sensor and the detectors. The sensors can thus be placed in space-constrained and electronically hostile locations. We used silica optical fibres that withstand high radiation doses, high temperatures, and electromagnetic interference. We use a single photon counter and a photomultiplier to detect the transmitted scintillation radiation. We have shown that selected optical fibres, combined with different scintillation materials, are suitable for measuring gamma radiation levels in hundreds of kBq. We present the architecture of the dosimeter and its experimental characterisation with several combinations of optical fibres, detectors, and scintillation crystals. [ABSTRACT FROM AUTHOR]

In this study, we demonstrated the process of an integrated apparatus for decay time analysis and gamma radiation measurement with a liquid-scintillator-based cadmium-doped zinc oxide (CZO) nanomaterial. Generally, time-resolved photon counting is an essential analysis method in the field of precision measurement in the quantum domain. Such photon counting equipment requires a pulse laser that can be repeated quickly while having a sharp pulse width of picoseconds or femtoseconds as a light source. Time-correlated single photon counting (TCSPC) equipment, which is currently a commercial product, is inconvenient for recent development research because the scintillator size and shape are limited. Here, neodymium-doped yttrium aluminum garnet (Nd/YAG) laser TCSPC equipment was constructed to analyze the fluorescence characteristics of scintillators having various sizes and shapes. Then, a liquid scintillator added with CZO nanomaterial was prepared and the Nd/YAG laser TCSPC equipment test was performed. As a result of measuring the scintillator using the manufactured Nd/YAG laser TCSPC equipment, the non-CZO liquid scintillator was analyzed at 2.30 ns and the liquid scintillator equipped with CZO-loaded nanomaterial was analyzed at 11.95 ns. It showed an error within 5% when compared with the result of commercial TCSPC equipment. In addition, it was verified that the Nd/YAG laser TCSPC system can sufficiently measure the decay time in nanoseconds (ns). Moreover, it was presented that the Compton edge energy of Cs−137 is 477.3 keV, which hardly generates a photoelectric effect, and Compton scattering mainly occurs. [ABSTRACT FROM AUTHOR]

Fast neutron active interrogation is a powerful method for detecting shielded contraband, including explosives, narcotics, and special nuclear material. Pulsed neutron sources can produce intense, time-dependent gamma-ray signatures of contraband, but the detection of those gamma rays is frequently challenging due to high detector pileup. Organic scintillators are fast and cost-effective gamma-ray detectors and thus could be well suited for this application if they can provide adequate gamma-ray spectroscopy. We discuss the use of maximum likelihood estimation maximization based spectral reconstruction techniques for organic scintillators to reconstruct the inelastic scattering and capture gamma-ray spectra produced in neutron active interrogation. Several contraband simulants were irradiated with a pulsed deuterium-tritium neutron generator, and organic liquid scintillators were used to record the emitted radiation signatures. The gamma-ray spectra are time-gated based on the measured neutron pulse time profile, which is shown to be able to improve the signal-to-background ratio for contraband gamma-ray signatures. We isolated several major gamma-ray signatures in the reconstructed spectra that correspond to contraband constituent elements, allowing for the identification of potential contraband objects. We additionally show that the reconstructed gamma-ray spectra can be used to measure sample stoichiometry and discriminate benign from contraband simulant objects. [ABSTRACT FROM AUTHOR]

Waseda University and Tokyo Tech are developing a 50 kg-class small satellite, tentatively named INnovative Space Probe for Imaging R-process Emission (I N S P I R E), which is scheduled for launch in 2027. The primary detector of the satellite is a BOX-type Compton Camera (CC-Box) that enables to observe low energy gamma rays (30 keV − 200 keV) in pinhole mode and high energy gamma rays (150 keV − 3 MeV) in Compton mode. The CC-Box consists of a pixelized Ce:GAGG scintillator array using a depth-of-interaction (DOI) structure, which is optically coupled to an MPPC array. The Ce:GAGG arrays are also positioned on the side of detector to enhance its sensitivity. Herein, we describe the detailed design of the CC-Box, its data processing flow, and its weight and power specifications. We then assess the anticipated performance of the detector in terms of continuum and line sensitivities, together with a simulation of the Crab nebula observation. Finally, a brief review of the experimental results is performed using hands-on devices already implemented in nuclear medicine and atmospheric observations, such as gamma-ray imaging of thunderclouds. [ABSTRACT FROM AUTHOR]

In a compact multi-radiation imaging system, the substitution of traditional charge-coupled devices with a plastic scintillators array coupled with silicon photomultiplier detectors significantly enhances the radiation tolerance of the detection and imaging module, thereby reducing the system footprint. We present a detailed structure of a compact fast neutron/gamma-ray dual-modality imaging system based on a plastic scintillators array and evaluate its performance in imaging various samples. The detector array consists of nine 14.7 × 14.7 × 100 mm3 EJ-276 plastic scintillators coupled with corresponding silicon photomultiplier units, arranged in a 3 × 3 grid. The usage of EJ-276 plastic scintillators allows for discrimination between neutron and gamma signals through pulse shape discrimination techniques, enabling data separation between neutrons and gamma rays. In this paper, we present the experimental procedure and results of fast neutron-gamma imaging for objects containing aluminum and polyethylene materials. Fast neutrons and gammas are delivered by an Cf-252 source. The experimental results demonstrate that the system achieves dual-modality grayscale imaging and has resolution for sample thickness. Reconstructed image contrast allows qualitative differentiation of sample materials, especially detecting low-Z materials encapsulated by high-Z materials. [ABSTRACT FROM AUTHOR]

The response of a gamma-ray spectrometer is generally determined by analyzing full-energy peaks. However, full-energy peaks cannot be measured easily in the case of scintillation detectors that consist of light elements, such as glass scintillators. Only a strong Compton plateau appears in the spectrum of such detectors. Therefore, Compton edgers were used to evaluate the response of these detectors. The response of a low-resolution 6 Li-glass detector to gamma rays was measured for the first time by a coincidence method with a high-resolution LaBr 3 :Ce detector using cascade gamma rays (2.75 and 1.37 MeV) from a 24Na source. Coincidence gates were applied at the peaks of the spectrum of the LaBr 3 :Ce detector at the 0.51 MeV annihilation peak, and the sum peaks of a gamma ray and a backscattered gamma ray. By analyzing the gated spectra of the 6 Li-glass detector, the energy-dependent detector response (i.e., the output strength and its dispersion) was determined. • Evaluation of the response characteristics, including signal output and broadening, of a low-resolution 6Li-glass detector to gamma rays up to approximately 2.5 MeV. • Coincidence measurement of cascade gamma rays emitted from a 24Na source with a high-resolution detector, a LaBr 3 :Ce detector. • Peak analysis of the spectra of the 6Li-glass detector gated at gamma ray peaks of the LaBr3:Ce detector. [ABSTRACT FROM AUTHOR]

An organic scintillator-based radiation portal monitor (RPM) prototype system with imaging capabilities has been developed based on the neutron–gamma emission tomography technique. The technique enables rapid detection and precise location of small amounts of special nuclear materials, such as plutonium, using time and energy correlations between fast neutrons and gamma rays from spontaneous fission with low false-alarm rates. These capabilities, in addition to state-of-the-art detection of various gamma-emitting sources, enables the novel imaging RPM concept to efficiently address global security threats from terrorism and the proliferation of nuclear weapons. The detector approach is simple and versatile and can easily be adapted for different applications in nuclear security, public safety, nuclear emergency response, and radiological surveying. In this work, basic performance parameters of the imaging RPM prototype system developed at KTH have been evaluated. [ABSTRACT FROM AUTHOR]

In the present article, the influence of the activator concentration and impurity content of raw materials on the luminescence and scintillation properties of Li2CaSiO4 was studied. Polycrystalline powder material was obtained by the sol–gel method. It was shown that europium had limited solubility in the host lattice with a limiting concentration proximate to 0.014 formula units. The maximum intensity of photoluminescence was observed with a divalent europium concentration of 0.002 formula units; the light yield under alpha-particle excitation was measured to be 21,600 photons/MeV for ~200 μm of coating, and under neutron excitation, it was calculated to be 103,800 photons/n, the scintillation kinetics was characterized by an effective decay time of 157 ns. These properties and the transparency in the visible spectrum make it possible to produce scintillation screens with a coating of Li2CaSiO4 for detecting neutrons, alpha particles and low-energy beta radiation. The low Zeff (~15) of this compound makes it less sensitive to gamma rays. The 480 nm blue emission peak makes this material compatible with most commercial PMT photocathodes, CCD cameras and silicon photomultipliers, which have a maximum quantum efficiency in the blue–green spectral region. [ABSTRACT FROM AUTHOR]

We implemented a didactic experiment to study the angular correlation between the two gamma rays emitted in typical 60Co radioactive decays. We used two NaI(Tl) scintillators, already available in our laboratory, and a low-activity 60Co source. The detectors were mounted on two rails, with the source at their center. The first rail was fixed, while the second could be rotated around the source. We performed several measurements by changing the angle between the two scintillators in the range from 90° to 180°. Dedicated background runs were also performed, removing the source from the experimental setup. We found that the signal rate increases with the angular separation between the two scintillators, with small discrepancies from the theoretical expectations. [ABSTRACT FROM AUTHOR]

Sensitive and fast detection of neutrons and gamma rays is vital for homeland security, high‐energy physics, and proton therapy. Fast‐neutron detectors rely on light organic scintillators, and γ‐ray detectors use heavy inorganic scintillators and semiconductors. Efficient mixed‐field detection using a single material is highly challenging due to their contradictory requirements. Here we report hybrid perovskites (C8H12N)2Pb(Br1−xClx)4 that combine light organic cations and heavy inorganic skeletons at a molecular level to achieve unprecedented performance for mixed‐field radiation detection. High neutron absorption due to a high density of hydrogen, strong radiative recombination within the highly confined [PbX6]4− layer, and sub‐nanometer distance between absorption sites and radiative centers, enable a light yield of 41 000 photons/MeV, detection pulse width of 2.97 ns and extraordinary linearity response toward both fast neutrons and γ‐rays, outperforming commonly used fast‐neutron scintillators. Neutron energy spectrum, time‐of‐flight based fast‐neutron/γ‐ray discrimination and neutron yield monitoring were all successfully achieved using (C8H12N)2Pb(Br0.95Cl0.05)4 detectors. We further demonstrate the monitoring of reaction kinetics and total power of a nuclear fusion reaction. We envision that molecular hybridized scintillators open a new avenue for mixed‐field radiation detection and imaging. [ABSTRACT FROM AUTHOR]

NaI(Tl) scintillators can detect thermal neutrons with surprising efficiency, even in the presence of ambient gamma radiation. This is due to a peculiarity of the 128I level scheme. Deexcitation cascades following neutron captures in 127I, a main constituent of NaI with quite large neutron capture cross section, unexpectedly often involve the 167.4 keV state of 128I with 175 ns half-life, which feeds another isomeric level at 137.9 keV having a half-life of 845 ns. The 29.5 keV transition between both levels, as well as the subsequent deexcitation sequence to ground state comprising 137.9 keV sum energy, are almost certainly absorbed in the crystal. Signals including three scintillation pulses within few microseconds, the first one caused by a prompt part of the cascade, the second and third one disclosing 30 and 138 keV energy depositions and characteristic delays, are clearly related to such neutron captures. Double-pulse sequences comprising only the primary pulse and a delayed 138 keV signal are also distinctive but more prone to load-dependent background by random pulse pileups. This article demonstrates neutron detection with a Ø2” $\times2$ ” NaI(Tl) scintillation detector by finding and analyzing such double- and triple-pulse sequences in digitized detector signals. It quantifies effect and background rates as a function of the detector load ranging up to 30 kcps. Complementary measurements with a 6Li codoped Ø2” $\times2$ ” NaI(Tl) (NaIL) scintillator allow relating the neutron detection yield by delayed-coincidence counting to the 6Li capture rate in the same crystal and thus to evaluate prospects and limits of this technique. [ABSTRACT FROM AUTHOR]

Sodium iodide crystal co-doped with thallium and lithium is a promising scintillator with wide application prospects for dual gamma neutron detection. In this study, a compact gamma/neutron detector was developed based on 2-inch NaI(Tl+Li) (NaIL) scintillator readout with 8 × 8 silicon photomultiplier (SiPM) array. Dedicated transimpedance amplifier circuit was developed for the SiPM array. The energy resolution and response linearity with the SiPM array were evaluated and compared to those obtained with photomultiplier tube (PMT) readout. The energy resolution for 661.6 keV gamma rays was measured as 7.0% and 6.5% with SiPM array and PMT, respectively. The linear response of the SiPM array is almost the same as that of the PMT in the energy range up to ~4 MeV. Neutron and gamma pulse shape discrimination was evaluated by acquiring the pulse waveforms with a digitizer (12 bit/250 MSPS) and off-line analysis. The best figure of merit (FOM) was measured as 3.75 for the SiPM array with optimized parameters, close to the performance measured with PMT (FOM = 4.07). The experimental results show that the NaIL scintillator readout with SiPM array exhibit energy resolution equivalent to NaI(Tl) gamma detectors and excellent neutron/gamma discrimination, making it especially suitable for compact devices requiring gamma and neutron dual detection capabilities. [ABSTRACT FROM AUTHOR]

The CALorimetric Electron Telescope (CALET) on the International Space Station consists of a high-energy cosmic-ray CALorimeter (CAL) and a lower-energy CALET Gamma-ray Burst Monitor (CGBM). CAL is sensitive to electrons up to 20 TeV, cosmic-ray nuclei from Z = 1 through Z ∼ 40, and gamma rays over the range 1 GeVâ€"10 TeV. CGBM observes gamma rays from 7 keV to 20 MeV. The combined CAL-CGBM instrument has conducted a search for gamma-ray bursts (GRBs) since 2015 October. We report here on the results of a search for X-ray/gamma-ray counterparts to gravitational-wave events reported during the LIGO/Virgo observing run O3. No events have been detected that pass all acceptance criteria. We describe the components, performance, and triggering algorithms of the CGBMâ€"the two Hard X-ray Monitors consisting of LaBr3(Ce) scintillators sensitive to 7 keVâ€"1 MeV gamma rays and a Soft Gamma-ray Monitor BGO scintillator sensitive to 40 keVâ€"20 MeVâ€"and the high-energy CAL consisting of a charge detection module, imaging calorimeter, and the fully active total absorption calorimeter. The analysis procedure is described and upper limits to the time-averaged fluxes are presented. [ABSTRACT FROM AUTHOR]

Scintillation detection has attracted great interest in nuclear medicine, nuclear radiation detection, high-energy physics, and non-destructive inspection. The elpasolite crystals with Ce3+ dopants are promising for these endeavors due to their modest light yield and extremely good proportionality when excited by the gamma ray. Moreover, the 6Li and 35Cl isotopes in elpasolite crystals endow them with excellent neutron detection capability. These features allow not only a high energy resolution but also a high detection sensitivity. The elpasolite scintillators also enable the precisely dual detection of gamma/neutron signals through pulse height discrimination (PHD) or pulse shape discrimination (PSD). In this work, we review recent investigations on using the typical elpasolite scintillators, including Ce3+-doped Cs2LiYCl6 (CLYC), Cs2LiLaCl6 (CLLC), and Cs2LiLaBr6 (CLLB), for the monitoring of gamma rays and neutrons. The scintillation properties, detection mechanism, and elpasolite crystal structure are also discussed with the aim of improving high-energy ray detection ability. [ABSTRACT FROM AUTHOR]

Plastic scintillators (PS) allow design of portative lightweight devices for quantification of low‐activity radiation sources. We have recently suggested a new type of organic fluorophores based on triphenyl pyrazoline (PZ) derivatives with high fluorescence quantum yield showing high radioluminescence when combined with a polyvinyltoluene (PVT) matrix. In this publication we report on radioluminescence properties of the PZ−X family with various halogen substitution (X=F, Cl, Br, I), or having vinyl functional group (vPZ, X=vinyl). PS based on such fluorophores and PVT matrix can be prepared as bulk samples, micrometer size beads or cladding on optical fibers. Application of fluorophores with vinyl functional groups enabled their enhanced interaction with the matrix due to covalent bonding between the components. We demonstrate high performance of PZ−X fluorophores and especially vPZ fluorophore in fabrication of nanocomposites for detection of various types of radiation. Scintillators have enhanced gamma ray detection capabilities with an addition of triphenyl Bi, or Gd2O3 nanoparticles. High fluorescence quantum yield and luminosity of PZ fluorophores allows dramatical reduction of their content in PS systems. Mechanisms of energy transfer and conversion during scintillation process are discussed. Special consideration is given to enhancement of α/β and neutron/gamma (n/γ) pulse shape discrimination (PSD) function of the developed scintillators. [ABSTRACT FROM AUTHOR]

The Nevada National Security Site (NNSS), together with Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory, is developing a novel diagnostic to measure the reactivity of subcritical experiments (SCEs). This capability is known as neutron-diagnosed subcritical experiments (NDSEs). The decay of the fission gamma rays from the neutron-interrogated SCE is measured as a function of time with a large ($\sim 3$ -m diameter) detector wall consisting of 151 individual detector pixels. The data from this current mode measurement inform the neutron multiplication factor, $k_{\mathrm {eff}}$ , and thus the relative reactivity of the SCE. The NNSS developed the Gamma Array Simulation Toolkit (GAST) initially to help inform the design of the individual detector pixels and the 3.4-m diameter detector wall to be fielded as part of NDSEs. This toolkit is now being used to simulate and predict the performance of the final design of the individual detector pixels and the aggregate detector wall. Key detector characteristics evaluated from these simulations include impulse response, pulse height spectrum, number of photoelectrons per MeV, detector efficiency, and crosstalk between detector pixels. Collectively, the results of these simulations inform how well the fission gamma-ray die-off distribution from an NDSE measurement can be resolved. This is critical to determining the relative reactivity of the experiment. Furthermore, the GAST can be used to aid in the analysis of the experimental data from an NDSE measurement once the simulation has been benchmarked. [ABSTRACT FROM AUTHOR]

Currently, plastic (organic) scintillators are using in new type positron emission tomography (PET) devices such as J-PET. But, these type scintillators have low gamma energy detection performance. Therefore, an experimental method was proposed to improve gamma ray energy resolution of an organic scintillation detector composed of a BC-420 type crystal. To do this, a timing spectrometer using constant fraction discrimination method was used. Gamma rays from a 137Cs radioactive source were first detected directly then through the timing method, and the obtained results were compared. The results showed that used method is considerably successful in increasing the energy resolution of this type detector. So, it is believe that the J-PET detection performance will be able to enhance if the proposed method can be used in its electronics. [ABSTRACT FROM AUTHOR]