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Background Purpose Methods Results Conclusion Pencil Beam Scanning proton therapy has many advantages from a therapeutic point of view, but raises technical constraints in terms of treatment verification. The treatment relies on a large number of planned pencil beams (PB) (up to thousands), whose delivery is divided in several low‐intensity pulses delivered a high frequency (1 kHz in this study).The purpose of this study was to develop a three‐dimensional quality assurance system allowing to verify all the PBs’ characteristics (position, energy, intensity in terms of delivered monitor unit—MU) of patient treatment plans on a pulse‐by‐pulse or a PB‐by‐PB basis.A system named SCICOPRO has been developed. It is based on a 10 × 10 × 10 cm3 scintillator cube and a fast camera, synchronized with beam delivery, recording two views (direct and using a mirror) of the scintillation distribution generated by the pulses. A specific calibration and analysis process allowed to extract the characteristics of all the pulses delivered during the treatment, and consequently of all the PBs. The system uncertainties, defined here as average value + standard deviation, were characterized with a customized irradiation plan at different PB intensities (0.02, 0.1, and 1 MU) and with two patient's treatment plans of three beams each. The system's ability to detect potential treatment delivery problems, such as positioning errors of the treatment table in this work (1° rotations and a 2 mm translation), was assessed by calculating the confidence intervals (CI) for the different characteristics and evaluating the proportion of PBs within these intervals.The performances of SCICOPRO were evaluated on a pulse‐by‐pulse basis. They showed a very good signal‐to‐noise ratio for all the pulse intensities (between 2 × 10−3 MU and 150 × 10−3 MU) allowing uncertainties smaller than 580 µm for the position, 180 keV for the energy and 3% for the intensity on patients treatment plans. The position and energy uncertainties were found to be little dependent from the pulse intensities whereas the intensity uncertainty depends on the pulses number and intensity distribution. Finally, treatment plans evaluations showed that 98% of the PBs were within the CIs with a nominal positioning against 83% or less with the table positioning errors, thus proving the ability of SCICOPRO to detect this kind of errors.The high acquisition rate and the very high sensitivity of the system developed in this work allowed to record pulses of intensities as low as 2 × 10−3 MU. SCICOPRO was thus able to measure all the characteristics of the spots of a treatment (position, energy, intensity) in a single measurement, making it possible to verify their compliance with the treatment plan. SCICOPRO thus proved to be a fast and accurate tool that would be useful for patient‐specific quality assurance (PSQA) on a pulse‐by‐pulse or PB‐by‐PB verification basis. [ABSTRACT FROM AUTHOR]

The ability to distinguish multiple forms of plutonium from one another, such as oxide and metal, is paramount in areas of nuclear nonproliferation and international safeguards. In its metal form, plutonium can be readily used in a nuclear weapon, while oxide forms are associated with nuclear reactor fuel. Oxide-based plutonium forms emit neutrons with an energy spectrum that is significantly different from the fission neutrons that are emitted from plutonium metal. Organic scintillation detectors output pulses that are proportional to the neutron energy deposited, and therefore present a means of distinguishing these plutonium forms based on their energy spectra. In this work, metal and oxide forms of plutonium were measured using a handheld detection system based on an organic glass scintillator. Monte Carlo modeling of these experiments was performed to provide insight into the origin of the features in the observed light output spectra. Through analysis of multiple regions of these spectra, in a matter of minutes we were able to unambiguously discriminate oxide and metal plutonium forms from one another and from a plutonium-beryllium neutron source, which was considered for comparison because these sources are commonly used in industrial applications. The ability to discriminate weapons-usable material from nuclear reactor fuel has applications in nuclear treaty verification and safeguards. [ABSTRACT FROM AUTHOR]

Background: Inorganic scintillation detectors (ISDs) are promising for in vivo dosimetry in brachytherapy (BT). ISDs have fast response, providing time resolved dose rate information, and high sensitivity, attributed to high atomic numbers. However, the conversion of the detector signal to absorbed dose‐to‐water is highly dependent on the energy spectrum of the incident radiation. This dependence is comprised of absorbed dose energy dependence, obtainable with Monte Carlo (MC) simulation, and the absorbed dose‐to‐signal conversion efficiency or intrinsic energy dependence requiring measurements. Studies have indicated negligible intrinsic energy dependence of ZnSe:O‐based ISDs in Ir‐192 BT. A full characterization has not been performed earlier. Purpose: This study characterizes the intrinsic energy dependence of ZnSe:O‐based ISDs for kV X‐ray radiation qualities, with energies relevant for BT. Methods: Three point‐like ISDs made from fiber‐coupled cuboid ZnSe:O‐based scintillators were calibrated at the Swedish National Metrology Laboratory for ionizing radiation. The calibration was done in terms of air kerma free‐in‐air, Kair${K}_{{\mathrm{air}}}$, in 13 X‐ray radiation qualities, Q$Q$, from 25 to 300 kVp (CCRI 25–250 kV and ISO 4037 N‐series), and in terms of absorbed dose to water, Dw${D}_{\mathrm{w}}$, in a Co‐60 beam, Q0${Q}_0$. The mean absorbed dose to the ISDs, relative to Kair${K}_{{\mathrm{air}}}$ and Dw${D}_{\mathrm{w}}$, were obtained with the MC code TOPAS (Geant4) using X‐ray spectra obtained with SpekPy software and laboratory filtration data and a generic Co‐60 source. The intrinsic energy dependence was determined as a function of effective photon energy, Eeff${E}_{eff}$, (relative to Co‐60). The angular dependence of the ISD signal was measured in a 25 kVp (0.20 mm Al HVL) and 135 kVp beam (0.48 mm Cu HVL), by rotating the ISDs 180° around the fiber's longitudinal axis (perpendicular to the beam). A full 360° was not performed due to setup limitations. The impact of detector design was quantified with MC simulation. Results: Above 30 keV Eeff${E}_{eff}$ the intrinsic energy dependence varied with less than 5 ± 4% from unity for all detectors (with the uncertainty expressed as the mean of all expanded measurement uncertainties for individual Eeff${E}_{eff}$ above 30 keV, k = 2). Below 30 keV, it decreased with up to 17% and inter‐detector variations of 13% were observed, likely due to differences in detector geometry not captured by the simulations using nominal geometry. In the 25 kVp radiation quality, the ISD signal varied with 24% over a ∼45° rotation. For 135 kVp, the corresponding variation was below 3%. Assuming a 0.05 mm thicker layer of reflective paint around the sensitive volume changed the absorbed dose with 6.3% at the lowest Eeff${E}_{eff}$, and with less than 2% at higher energies. Conclusion: The study suggests that the ISDs have an intrinsic energy dependence relative to Co‐60 lower than 5 ± 4% in radiation qualities with Eeff${E}_{eff}\ $> 30 keV. Therefore, they could in principle be calibrated in a Co‐60 beam quality and transferred to such radiation qualities with correction factors determined only by the absorbed dose energy dependence obtained from MC simulations. This encourages exploration of the ISDs' applications in intensity modulated BT with Yb‐169 or other novel intermediate energy isotopes. [ABSTRACT FROM AUTHOR]

Time‐of‐Flight Positron Emission Tomography (ToF‐PET) is a medical imaging technique, based on the detection of two back‐to‐back γ‐photons generated from radiotracers injected into the body. Its limit is the ability of employed scintillation detectors to discriminate in time the arrival of γ‐pairs, that is, the coincidence time resolution (CTR). A CTR < 50 ps will enable fast imaging with ultralow radiotracer dose. Monolithic materials do not have simultaneously the required high light output and fast emission characteristics, thus the concept of scintillating heterostructure is proposed, where the device is made of a dense scintillator coupled to a fast‐emitting light material. Here a composite polymeric scintillator loaded with hafnium oxide nanoparticles is presented. This enhanced by +300% its scintillation yield, by surpassing commercial plastic scintillators. The nanocomposite is coupled to bismuth germanate oxide (BGO) realizing a multilayer metascintillator. The energy sharing between its components is observed, which activates the nanocomposite's fast emission enabling a net CTR improvement of 25% with respect to monolithic BGO. These results demonstrate that a controlled loading with dense nanomaterials is an excellent strategy to enhance the performance of polymeric scintillators for their use in advanced radiation detection and imaging technologies. [ABSTRACT FROM AUTHOR]

Open Hardware-based microcontrollers, especially the Arduino platform, have become a comparably easy-to-use tool for rapid prototyping and implementing creative solutions. Such devices in combination with dedicated front-end electronics can offer low-cost alternatives for student projects, slow control and independently operating small-scale instrumentation. The capabilities can be extended to data taking and signal analysis at mid-level rates. Two detector realizations are presented, which cover the readouts of proportional counter tubes and of scintillators or wavelength-shifting fibers with silicon photomultipliers (SiPMs). The SiPMTrigger realizes a small-scale design for coincidence readout of SiPMs as a trigger or veto detector. It consists of a custom mixed signal front-end board featuring signal amplification, discrimination and a coincidence unit for rates of up to 200 kHz. The nCatcher transforms an Arduino Nano to a proportional counter readout with pulse shape analysis: time over threshold measurement and a 10-bit analog-to-digital converter for pulse heights. The device is suitable for low-to-medium-rate environments up to 5 kHz, where a good signal-to-noise ratio is crucial. We showcase the monitoring of thermal neutrons. For data taking and slow control, a logger board is presented that features an SD card and GSM/LoRa interface. [ABSTRACT FROM AUTHOR]

• CeBr 3 and NaI (Tl) scintillators characterized with array of Silicon Photomultipliers. • Energy resolution improves with lower shaping time and higher SiPM over-voltage. • Temperature dependency of gain of SiPM array: ∼−0.81 %/°C for overvoltage of 2.5 Volts. • Temperature dependency of light yield for CeBr 3 : ∼−0.27 %/°C for −31 °C to +26 °C. • Temperature dependency of light yield for NaI (Tl): ∼+0.5 %/°C for −31 °C to +26 °C. Interaction of X-rays with a scintillation detector produces optical photons in the visible range. The spectral and spatial information of the X-ray can be derived by detecting these output photons using a Silicon Photomultiplier (SiPM). Two types of detector modules: CeBr 3 and NaI (Tl), coupled with an array of SiPM are presented here, which are being developed for the future space exploration programs. The development of the front end electronics (FEE) for the charge readout from SiPM for X-ray spectrometer application is presented here which is characterized for SiPM's over-voltages and shaping amplifier's time constant. In this article, both the detector modules are subjected to a wide temperature range to establish a relationship of the SiPM's gain, energy resolution and scintillators' output photon yield with ambient temperature. The test results show that energy resolution improves with higher over-voltage of SiPM and also with lower operating temperature. The gain of the SiPM array shows negative temperature dependence of ∼−0.81 %/°C for an over-voltage of 2.5 Volts. To derive the temperature dependency of scintillators' output photons, gain of the SiPM array was made constant by operating it at a fixed over-voltage for a wide temperature range. With the constant gain of SiPM, CeBr 3 scintillator shows negative temperature coefficient of ∼−0.27 %/°C and NaI (Tl) shows positive temperature coefficient of ∼+0.5 %/°C for the light output in the temperature range of −31 °C to +26 °C. [ABSTRACT FROM AUTHOR]

The overall gain of a scintillation detector is temperature-dependent, leading to a drift in the measured gamma energy spectrum with changes in temperature. To mitigate this effect, a temperature drift correction is essential prior to conducting gamma spectrum analysis. In this study, the detector gain ratio is determined by comparing the positions of the same background peak across different spectra. Subsequently, the original spectrum is adjusted accordingly to obtain a gamma spectrum free from temperature drift. Experimental results demonstrate that after implementing this correction, the relative deviation of the 57Co characteristic peak positions in the gamma spectrum measured by the NaI(Tl) detector is reduced from 18.64% to 0.91%. Furthermore, by performing energy calibration beforehand, the characteristic peak position can be utilized for secondary correction, further minimizing temperature drift. Our findings indicate that the relative deviation of the 22Na characteristic peak positions was reduced, respectively, to 0.51% and 0.46% through secondary correction. This approach, which utilizes the background peak for correction, avoids the need for additional radioactivity or circuitry and effectively mitigates peak drift. Overall, this method holds significant implications for enhancing the accuracy of gamma spectrum analysis. [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 recent years, indirect digital radiography detectors have been actively studied to improve radiographic image performance with low radiation exposure. This study aimed to achieve low-dose radiation imaging with a thick scintillation detector while simultaneously obtaining the resolution of a thin scintillation detector. The proposed method was used to predict the optimal point spread function (PSF) between thin and thick scintillation detectors by considering image quality assessment (IQA). The process of identifying the optimal PSF was performed on each sub-band in the wavelet domain to improve restoration accuracy. In the experiments, the edge preservation index (EPI) values of the non-blind deblurred image with a blurring sigma of σ = 5.13 pixels and the image obtained with optimal parameters from the thick scintillator using the proposed method were approximately 0.62 and 0.76, respectively. The coefficient of variation (COV) values for the two images were approximately 1.02 and 0.63, respectively. The proposed method was validated through simulations and experimental results, and its viability is expected to be verified on various radiological imaging systems. [ABSTRACT FROM AUTHOR]

The article describes a prototype device for monitoring the level of phase separation, which can be used for operational control of the delayed coking process in the petrochemical industry. A scheme and design of an experimental device developed by the authors, consisting of an organic plastic scintillator and an array of silicon photomultipliers, is presented. A computer simulation of the response of a scintillation detector under conditions of the actual geometry of the coke drum is presented. Experimental results demonstrating the performance of the device are presented. [ABSTRACT FROM AUTHOR]

The temperature effect plays an important role in the response function and efficiency of detectors. In this study, the behavior of doped NaI (Tl) and plastic scintillators was evaluated and compared with temperature changes, in a similar condition, for the first time. The detection system uses an experimental setup consisting of a 60Co source, NaI (Tl) detector, and a plastic scintillation detector. The results show that the recorded count rates from NaI (Tl) detector have a direct relation with temperature and lead to a 0.15%/°C error in the count rate. But in the same condition, the acquired count rates from the plastic scintillator detector were reduced with temperature increasing with a 0.57%/°C error in the count rate (inverse relation). Also, in this work, Linear and second-order polynomial regression were implemented on the recorded count rates from scintillators to compensate temperature effect. Finally, the acquired results were evaluated using the relative error (%) and diagram slope which expressed the superiority of the polynomial regression. Using this correction technique, the count rate changes reached to least and are stable with temperature fluctuations. The results of this research can be suitable for the industrial application of NaI (Tl) and plastic scintillators in level gauging, thickness gauging, and other nuclear gauging systems. [ABSTRACT FROM AUTHOR]

The characteristics of neutron scintillation detectors built on monolithic and heterogeneous scintillators containing 6Li were studied. The detectors were tested on a thermal neutron beam and on a stand with a source of γ-quanta 60Co. To process the signals received from the detector with a monolithic scintillator, three different γ-radiation discrimination algorithms were used: registration of pulses at a constant threshold and selection according to the pulse shape using two digital signal separation methods: charge integration and pulse duration measurement. For a homogeneous scintillator, pulse shape selection methods work approximately the same when separating thermal neutrons and γ-quanta and are significantly inferior to the method of registration at a constant threshold. In this case, the quality of the n/γ separation is worse than the result obtained with a heterogeneous scintillator when recording at a constant threshold. The purpose of the work is to compare the results of using digital methods for discrimination of gamma-quanta with the results obtained using heterogeneous scintillators. [ABSTRACT FROM AUTHOR]

We developed machine learning algorithms for distinguishing scintillation signals from a plastic-liquid coupled detector known as a phoswich. The challenge lies in discriminating signals from organic scintillators with similar shapes and short decay times. Using a single-readout phoswich detector, we successfully identified y radiation signals from two scintillating components. Our Boosted Decision Tree algorithm demonstrated a maximum discrimination power of 3.02 ± 0.85 standard deviation in the 950 keV region, providing an efficient solution for self-shielding and enhancing radiation detection capabilities. [ABSTRACT FROM AUTHOR]

A general description of the dynamics of nonequilibrium carriers in multicomponent activated scintillation materials with a compositional disorder of the crystalline matrix is developed and applied for studying the excitation transfer and timing properties of lutetium–yttrium oxyorthosilicate (LYSO). The energy structure, the density of states, and the effective potential of LSO and YSO crystals have been calculated by using the Quantum Espresso package. An analytical form of the potential fluctuations due to compositional disorder is suggested in the pseudopotential approximation. The spatial distribution of lutetium and yttrium cations in the LYSO crystal has been simulated by the Monte Carlo method using the thermodynamic approach for three qualitatively different cases of cation distribution: uniform, heterogeneous neighboring, and clustered. The impact of the compositional disorder on electron migration is found to be qualitatively different in four typical regions of electron energy. The density of localized states in LYSO calculated using the coherent potential approximation (CPA) and the quasiclassical approach is comparable to the density of secondary carriers expected in an ionization track and might have significant influence on the migration of thermalized carriers. The transport mean free path of nonlocalized electrons limited by elastic scattering on pseudopotential fluctuations is shown to be substantially longer than that due to longitudinal optical phonon emission in the low-energy region (calculated using CPA) and the high-energy region (calculated using the Born approximation). The scattering on pseudopotential fluctuations is important for intermediate-energy electrons due to a substantial influence of the core potential fluctuations on high-energy branches. [ABSTRACT FROM AUTHOR]

Boron Neutron Capture Therapy (BNCT) is a binary cancer therapy where a low energy neutron beam is incident upon a patient who has been administered a tumour-seeking 10B loaded compound. The neutron capture reaction on 10B results in the production of two short range particles, 7Li and 4He, that deposit all of their energies within the targeted cell. However, accurate, online dosimetry during BNCT is challenging as it requires knowledge of both the neutron fluence and 10B concentration in cells. An additional product in the neutron capture reaction on 10B is a 478 keV prompt gamma ray, and if the production vertices of these gamma rays could be imaged by an external camera, the density of the vertices could be used to infer the dose delivered to the patient. In this study, the feasibility of using an array of LaBr3 scintillators as a modified Compton camera for prompt gamma imaging during BNCT was investigated using Geant4 simulations. These simulations demonstrated that a phantom containing a 3 cm diameter region of 400 ppm 10B could be reconstructed using clinically relevant neutron fluences. This result opens up more possibilities for future research to improve dosimetry during BNCT. [ABSTRACT FROM AUTHOR]

(1) Background: High dose gradients and manual steps in brachytherapy treatment procedures can lead to dose errors which make the use of in vivo dosimetry (IVD) highly recommended for verifying brachytherapy treatments. A new procedure was presented to obtain a calibration factor which allows fast and robust calibration of plastic scintillation detector (PSD) probes for the geometry of a compact phantom using Monte Carlo simulations. Additionally, characterization of PSD energy, angular, and temperature dependences was performed. (2) Methods: PENELOPE/PenEasy code was used to obtain the calibration factor. To characterize the energy dependence of the PSD, the signal was measured at different radial and transversal distances. The sensitivity to the angular position was characterized in axial and azimuthal planes. (3) Results: The calibration factor obtained allows for an absorbed dose to water determination in full scatter conditions from ionization measured in a mini polymethylmethacrylate (PMMA) phantom. The energy dependence of the PSD along the radial distances obtained was (2.3 ± 2.1)% (k = 1). The azimuthal angular dependence measured was (2.6 ± 3.4)% (k = 1). The PSD response decreased by (0.19 ± 0.02)%/°C with increasing detector probe temperature. (4) Conclusions: The energy, angular, and temperature dependence of a PSD is compatible with IVD. [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]

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]

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]

Dual-energy computed tomography (CT) provides a better material classification capability than traditional CT. A scintillator is an essential component that determines the optical resolution, detective quantum efficiency, and energy separation of the dual-layer dual-energy CT system. In this paper, we propose a new dual-layer scintillator combination composed of CsI:Tl and LYSO:Ce for dual-energy CT imaging. The x-ray attenuation physical process of CsI:Tl and LYSO:Ce combination is simulated on Geant4. The energy distribution and luminescence of different thicknesses of the scintillator combination are investigated by simulation experiments. Then, the optimal thicknesses of the combination are designed based on simulation results. Furthermore, a dual-layer dual-energy CT system using the scintillator combination is built, and practical dual-energy imaging experiments are implemented in the system. Simulation results indicate that the CsI:Tl and LYSO:Ce combination can effectively realize dual-energy detection. The optimal thickness is 100 μm for CsI:Tl and 500 μm for LYSO:Ce. Practical experiments show that the dual-energy CT system using the CsI:Tl and LYSO:Ce combination has low noise. Materials of the metal mixture sample and the igneous rock sample are correctly separated using the dual-energy data obtained by the CsI:Tl and LYSO:Ce combination. Therefore, the CsI:Tl and LYSO:Ce combination is expected to be used in dual-energy CT imaging studies of complex materials, such as metals, bones, and rocks. [ABSTRACT FROM AUTHOR]

There is a growing demand for materials for detecting ionizing radiation, which has led to the expansion of research and development of new scintillators. Typically, scintillators are synthesized by crystallizing materials at high temperatures, and their photoluminescence (PL) is difficult to tune in the visible spectral range. Therefore, composite materials based on CsPbBr3 perovskite nanocrystals (PNCs), which have a high average atomic number and a long charge-carrier diffusion length, are of particular interest and may be used for detecting ionizing radiation. Unlike bulk scintillators, PNCs are synthesized in solution at relatively low temperatures, with the PL tunable throughout the visible spectrum. The main problem limiting the widespread use of PNCs is their low stability upon contact with the environment. This study presents the results of experiments on the encapsulation of PNCs in a polystyrene matrix, the evaluation of the changes in the luminescence quantum yield (QY) over time, and the development of a technique for studying the amplitude characteristics of signals recorded during the interaction of α-particles with composite materials based on CsPbBr3 PNCs and polystyrene. The study has shown that composite samples based on PNCs and polystyrene retain a stable luminescence QY for two weeks. Using a 241Am source with a characteristic α-particle energy of about 4.6 MeV and γ-ray energy of 60 keV, the light output values were calculated for the samples studied. The maximum light output was 20% of that of the standard "fast" plastic scintillator (POPOP) at a volume fraction of PNCs in the composite of less than 1%, which indicates the prospect of PNCs as a basis for composite scintillators and their further use in X-ray diagnosis. [ABSTRACT FROM AUTHOR]

The analysis of amplitude spectra from a thin polystyrene-based scintillation counter on muon-enriched and hadron beams of channel 18 of the U-70 accelerator complex in Protvino has been presented. On the basis of statistics of 150 million events on the Hyperon-M setup, the contribution of the -fragmentation processes are highlighted and the cross sections of these processes on hadron and pion beams with a momentum of 7 GeV/c have been measured. In the future, the obtained result may be of interest for the method of analyzing the age of gas fields based on the concentration of helium in natural gas, the formation of which is possible in the reaction of fragmentation of carbon nuclei in interactions induced by high-energy cosmic muons. [ABSTRACT FROM AUTHOR]

To minimize the environmental burden of the disposal of spent nuclear fuel, nuclide management process is one of good candidates to separate and collect major nuclides in the spent nuclear fuel. After high heat load nuclides, high mobile nuclides, and long-lived nuclides are separated, collected, and fabricated as the waste form for the disposal. From safeguards perspective, nuclear material of the TRU/RE waste form should be verified. The amount of Plutonium can be estimated by Cm/Pu ratio using burnup code calculations and Cm-244 measurement. In this study, a fast neutron coincidence counter for Cm-244 neutron measurement of the TRU/RE waste form was designed with EJ-276 plastic scintillation detectors using PTRAC of MCNP6.2. The preliminary experimental performance evaluation using one EJ-276 plastic scintillation detector was conducted. And total and coincidence counting efficiency using a Cf-252 neutron source was calculated with respect to the number of detectors. [ABSTRACT FROM AUTHOR]

The paper presents the results of a comprehensive study of the structural-phase composition, morphology, optical, luminescent, and scintillation characteristics of thick ZnO films fabricated by magnetron sputtering. By using a hot ceramic target, extremely rapid growth (~50 µm/h) of ZnO microfilms more than 100 µm thick was performed, which is an advantage for the industrial production of scintillation detectors. The effects of post-growth treatment of the fabricated films in low-temperature plasma were studied and a significant improvement in their crystalline and optical quality was shown. As a result, the films exhibit intense near-band-edge luminescence in the near-UV region with a decay time of <1 ns. Plasma treatment also allowed to significantly weaken the visible defect luminescence excited in the near-surface regions of the films. A study of the luminescence mechanisms in the synthesized films revealed that their near-band-edge emission at room temperature is formed by phonon replicas of free exciton recombination emission. Particularly, the first phonon replica plays the main role in the case of optical excitation, while upon X-ray excitation, the second phonon replica dominates. It was also shown that the green band peaking at ~510 nm (2.43 eV) is due to surface emission centers, while longer wavelength (>550 nm) green-yellow emission originates mainly from bulk parts of the films. [ABSTRACT FROM AUTHOR]

The work describes features of the procedure for obtaining a response matrix to neutron radiation with energies from 1 to 19 MeV for a single-crystal stilbene scintillation detector. This response matrix is subsequently used in solving the problem of unfolding the neutron energy distribution at the detector location. The procedure for obtaining the matrix includes both experimental work and simulations of nuclear physics processes. In order to carry out the simulations, the Geant4 library package with the connected optical physics accounting module was used. The resulting matrix can be used as part of the amplitude method for unfolding the spectra of neutrons with energies in the range of 1–19 MeV with a step of 0.1 MeV. The obtained response matrix takes into account the main physical processes and instrumental effects of detectors based on organic scintillators, including the dependence of the light yield in the scintillator on the type and energy of charged particles, as well as the energy resolution of the detector depending on the energy of detected particles. In comparison with earlier results obtained using response matrices that do not take into account the above formation features of hardware spectra, it was possible to reduce the lower limit of the detected neutron energy from 1.5 to 1.0 MeV, as well as to increase the reliability of unfolded neutron energy distributions at the measurement point. The error in determining the neutron energy in the range of 1–15 MeV was not more than 200 keV. [ABSTRACT FROM AUTHOR]

In this advanced instructional laboratory, students explore complex detection systems and nondestructive assay techniques used in the field of nuclear physics. After setting up and calibrating a neutron detection system, students carry out timing and energy deposition analyses of radiation signals. Through the timing of prompt fission neutron signals, multiplicity counting is used to carry out a special nuclear material (SNM) nondestructive assay. Our experimental setup is comprised of eight trans-stilbene organic scintillation detectors in a well-counter configuration, and measurements are taken on a spontaneous fission source as well as two (α,n) sources. By comparing each source's measured multiplicity distribution, the resulting measurements of the (α,n) sources can be distinguished from that of the spontaneous fission source. Such comparisons prevent the spoofing, i.e., intentional imitation, of a fission source by an (α,n) neutron source. This instructional laboratory is designed for nuclear engineering and physics students interested in organic scintillators, neutron sources, and nonproliferation radiation measurement techniques. [ABSTRACT FROM AUTHOR]

An indirect conversion X-ray detector uses a scintillator that utilizes the proportionality of the intensity of incident radiation to the amount of visible light emitted. A thicker scintillator reduces the patient's dose while decreasing the sharpness. A thin scintillator has an advantage in terms of sharpness; however, its noise component increases. Thus, the proposed method converts the spatial resolution of radiographic images acquired from a normal-thickness scintillation detector into a thin-thickness scintillation detector. Note that noise amplification and artifacts were minimized as much as possible after non-blind deconvolution. To accomplish this, the proposed algorithm estimates the optimal point-spread function (PSF) when the structural similarity index (SSIM) and feature similarity index (FSIM) are the most similar between thick and thin scintillator images. Simulation and experimental results demonstrate the viability of the proposed method. Moreover, the deconvolution images obtained using the proposed scheme show an effective image restoration method in terms of the human visible system compared to that of the traditional PSF measurement technique. Consequently, the proposed method is useful for restoring degraded images using the adaptive PSF while preventing noise amplification and artifacts and is effective in improving the image quality in the present X-ray imaging system. [ABSTRACT FROM AUTHOR]

Also related to nonlinear processes, Yang I et al. i outline in another Perspective the state of the art of rare-earth-doped upconversion (UC) nano- and microparticles.[18] Specifically, authors provide the main keys that determine the luminescence efficiency of single UC systems. Our key physiological functions and economic activity depend on the constant driving force of light.[1] Over the last few decades, incandescent and fluorescent lamps have been surpassed by electroluminescent semiconductors, giving birth to a new technology, so-called Solid State Lighting (SSL). [Extracted from the article]

This paper is devoted to the current status of the novel fully active 3D (three-dimensional) fine-grained scintillator detector SuperFGD as a main part of the near off-axis detector upgrade program for the T2K experiment. The following important components related to the SuperFGD such as SuperFGD electronics and mechanics, wavelength shifting (WLS) fibers, and light emitting diode (LED) calibration system are also discussed here as well as the detector's near future. [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]

trans-Stilbene single crystals are of great interest for researchers as scintillators characterized by a high specific light yield. Bulk trans-stilbene single crystals have been grown from an anisole solution. The transmission and photoluminescence spectra have been recorded, and the single-crystal photoluminescence quenching kinetics has been investigated. The scintillation properties of an element (17 × 12 × 5 mm in size) prepared from a grown trans-stilbene crystal, irradiated by γ radiation and X rays, have also been investigated. It is shown that the specific light yield of the obtained crystal is no less than that of a scintillation detector based on a trans-stilbene crystal (31.5 × 10 mm) grown from melt. [ABSTRACT FROM AUTHOR]

A new compact time-of-flight neutron detector is being planned for the identification and energy measurement of neutrons produced in nucleus-nucleus interactions at energies up to 4 AGeV at the BM@N experiment, located at the Nuclotron (Joint Institute for Nuclear Research, Dubna, Russia). This detector will be used to measure neutron yields and azimuthal flows, which should be sensitive to the equation of state of dense nuclear matter, as shown in various theoretical models It is proposed to use plastic scintillators produced at JINR and IFTP and silicon photomultipliers with a sensitive area of 6 × 6 mm2 for photon registration, one for each scintillation cell. To achieve the required neutron energy resolution (of the order of several percent) in the energy range up to 4 GeV, the time resolution of scintillation detectors should be 100−150 ps. The concept of a time-of-flight neutron detector is discussed. The results of measurements of the light yield and time resolution of several scintillation detector specimens of various sizes and two types of silicon photomultipliers are presented. [ABSTRACT FROM AUTHOR]

An experiment to search for 2ε-, εβ+ - and 2β+ -decays of 106Cd, using a 215 g cadmium tungstate scintillation crystal enriched at 66 % by 106Cd (106CdWO4) is carried out at the Gran Sasso underground laboratory (Italy). Events in the 106CdWO4 detector are recorded in (anti)coincidences with two large-volume CdWO4 scintillation counters. The design of the detector system, calibration and background measurements, methods, and results of data analysis to determine key detector characteristics are described. The experimental data are compared with Monte Carlo simulation results, and a background model is constructed. The radioactive contamination of the setup components is studied. The sensitivity of the experiment approaches the level of theoretical predictions for the 2Vεβ + -decay channel, while for other possible 2β-decay channels it is already on the level of lim T1/2 ~ 1021 - 1022 years. [ABSTRACT FROM AUTHOR]

Background: Arrays of thick segmented crystalline scintillators are useful x‐ray converters for image‐guided radiation therapy using electronic portal imaging (EPI) and megavoltage cone‐beam computed tomography (MV‐CBCT). Ionizing‐radiation‐only simulations previously showed relatively low modulation transfer function (MTF) in parallel‐element arrays because of beam divergence. Hence, a focused‐element geometry (matching the beam divergence) has been proposed. The "full" (ionizing and optical) MTF performance of such a focused geometry compared to its radiation‐only MTF has, however, not been fully investigated. Purpose: To study the full MTF performance of such arrays in a more realistic situation in which optical characteristics are also included using an in‐house detector model that supports light transport, and quantify the errors in MTF estimation when the optical stage is ignored. Methods: First, radiation (x‐ray and electron) transport was simulated. Then, transport of the generated optical photons was modeled using ScintSim2, an optical Monte Carlo (MC) code developed in MATLAB for simulation of two‐dimensional (2D) parallel‐ and focused‐element scintillator arrays. The full‐MTF responses of focused‐ and parallel‐element geometries, for a large array of 3 × 3 mm2 CsI:Tl detector elements of 10, 40, and 60 mm thicknesses, were examined. For each configuration, a composite line spread function (LSF) was calculated to obtain the MTF. Results: At the Nyquist frequency, for 10 mm‐thick central elements and 60 mm‐thick peripheral parallel elements, full‐MTF exhibited a drop of up to 15 and 79 times, respectively, compared with radiation‐only MTF. This was found to be partly attributable to the angular distribution of the light emerging from the detector‐element exit face and the dependence on its aspect ratio, since the light exiting thicker scintillators exhibited a more forward‐directed distribution. Focused elements provided an increase of up to nine times in peripheral‐area full MTF values. Conclusions: Full MTF was up to 79 times lower than radiation‐only MTF. Focused arrays preserved full MTF by up to nine times compared to parallel elements. The differences in the results obtained with and without inclusion of optical photons emphasize the need to include light transport when optimizing thick segmented scintillation detectors. Besides their application in detector optimization for radiotherapy megavoltage photon imaging, these findings can also be useful for other segmented‐scintillator‐based imaging systems, for example, in nuclear medicine, or in 2D detection systems for quality assurance of MR‐linacs. [ABSTRACT FROM AUTHOR]

Mg4Ta2O9 single crystals doped with 0.01, 0.1, and 1% Er were grown using the floating zone method, and their photoluminescence and scintillation properties were studied. X-ray diffraction analysis confirmed that all samples had a hexagonal structure of Mg4Ta2O9. The samples showed that the emission peak at 1550 nm was due to 4f−4f transitions of Er3+ ions, with quantum yields of 32.9, 46.6, and 18.0% for 0.01, 0.1, and 1% doping concentrations, respectively. All samples showed scintillation with a broad emission band at 350 nm due to charge transfer from Ta5+ to O2− ions and emission peak at 1550 nm due to 4f−4f transition of Er3+ ions. The dose rate response functions showed that the detection limit for all samples was 0.06 Gy/h for scintillation detector applications. [ABSTRACT FROM AUTHOR]

On the "Free Space Optical" (FSO) communication link, the atmospheric scintillation phenomena play a crucial role. The severity of the scintillation can seriously impair the FSO link's performance. In this article, we consider two wavelengths of FSO link, visible (638 nm) and infrared (980 nm), and measure their performances in a developed artificial scintillation simulation chamber, with the severity of scintillation ranged from low to high. The link performance is measured in terms of the eye pattern, optical power attenuation, signal-to-noise ratio (SNR), bit error rate (BER), etc., at the receiver side signal. As compared to the visible wavelength, 980 nm produces favorable performance in the high scintillation regime. [ABSTRACT FROM AUTHOR]

Materials with shielding capabilities against gamma radiation are important for nowadays applications in order to alleviate radiation damage. This study investigates the shielding characteristics of carbon fiber/epoxy composites incorporating lead nanoparticles (Pb-NP) of variable weight fractions. The composites in this experimental study are prepared using the handlayup vacuum bagging process at room temperature. Mass attenuation coefficients are calculated for composites with variable Pb-NP weight fractions based on radiation intensity measurements taken using NaI (Tl) scintillation detector. The results show that adding small fractions of lead nanoparticles to the matrix phase of the composite material leads to improving its shielding properties, including their linear attenuation coefficient, mass attenuation coefficient and the Half- Value Layer (HVL). The results also show that mass attenuation coefficients of composite material with added Pb-NPs are higher than those of pure lead. For validation purposes, the experimental results are compared to computational results obtained using MCNP5 code for the same weight fractions of Pb-NPs. The two sets of results were found to be in good agreement with a maximum relative error of ∼16%. [ABSTRACT FROM AUTHOR]

Random coincidences of events could be one of the main sources of background in the search for neutrino-less double-beta decay of 100 Mo with macro-bolometers, due to their modest time resolution. Scintillating bolometers as those based on Li 2 MoO 4 crystals and employed in the CROSS and CUPID experiments can eventually exploit the coincident fast signal detected in a light detector to reduce this background. However, the scintillation provides a modest signal-to-noise ratio, making difficult a pile-up pulse-shape recognition and rejection at timescales shorter than a few ms. Neganov–Trofimov–Luke assisted light detectors (NTL-LDs) offer the possibility to effectively increase the signal-to-noise ratio, preserving a fast time-response, and enhance the capability of pile-up rejection via pulse shape analysis. In this article we present: (a) an experimental work performed with a Li 2 MoO 4 scintillating bolometer, studied in the framework of the CROSS experiment, and utilizing a NTL-LD; (b) a simulation method to reproduce, synthetically, randomly coincident two-neutrino double-beta decay events; (c) a new analysis method based on a pulse-shape discrimination algorithm capable of providing high pile-up rejection efficiencies. We finally show how the NTL-LDs offer a balanced solution between performance and complexity to reach background index ∼ 10 - 4 counts/keV/kg/year with 280 g Li 2 MoO 4 ( 100 Mo enriched) bolometers at 3034 keV, the Q β β of the double-beta decay, and target the goal of a next generation experiment like CUPID. [ABSTRACT FROM AUTHOR]

Background: Plastic scintillators have been used as radiation detectors for the past few years, as they are water-equivalent and independent of the dose, dose rate, and angle of incidence. In addition, they are also independent of the presence of a magnetic field and could be used for in vivo dosimetry in an MR-Linac. With the advent of a new commercial scintillation detector, Blue Physics Model 10,its characterization has been performed on an MR-Linac with a view to future applications. Purpose: To perform the dosimetric characterization and study potential applications of a novel commercial plastic scintillation detector in a MR-Linac. Methods: Scintillation detector description, calibration procedure, short-term repeatability, dose-response linearity, dose-rate dependence, angular dependence, and temperature dependence have been studied. Percent-depth-dose (PDD) and beam profiles were measured for small fields and a standard field, as well as output factors, for comparison with other PTW detectors: a diamond diode and PinPoint and Semiflex 3D ionization chambers. The suitability of the plastic scintillator for in vivo dosimetry in a magnetic field has also been studied measuring the dose to a point in an anthropomorphic phantom while acquiring MR imaging. This measured dose was compared with that calculated with Monaco planning system and with that measured with a PTW Semiflex 3D chamber, the latter without acquiring MR images. Results: Short-term repeatability presented negligible variations (<0.4%) for 100 and 20 MU. Similar results were obtained for dose-response linearity and dose-rate dependence. A small angular dependence was determined, while the scintillator resulted practically independent of the temperature. PDDs showed excellent agreement except in the build-up region, and calculated penumbras with the profiles given by the scintillator were between the ones obtained with the diamond detector and the PinPoint ionization chamber. Measured OF with the scintillator were the highest between all detectors, 1.26% higher than the value obtained with the microdiamond for the smallest field measured, 0.5 × 0.5 cm2. Finally, the total dose to a point measured with the scintillator was 0.51% higher compared to that calculated by the planning system. Conclusion: The Blue Physics model 10 scintillation system showed excellent dosimetric characteristics. Its response independent of the temperature and the presence of a magnetic field make it suitable for in vivo dosimetry in an MR-Linac while acquiring MR images, which could solve the impossibility of performing a dosimetric QA for each adapted plan. Furthermore, its temporal resolution allows independent radiation pulses to be measured and visualized, which could be used in future applications. [ABSTRACT FROM AUTHOR]

A Hamamatsu R1828-01 model fast photomultiplier tube, i.e. having fast time response, was tested whether it can be utilized for the detection of alpha particles. An Eljen AJ-440 model ZnS(Ag) scintillator sheet was mounted on the front window of the PMT. In order to obtain best alpha detection performance, three different main amplifier models that are in our laboratory were used. The alpha energy resolution values were calculated through the amplifiers. Thus, the most appropriate amplifier model in the used ones was determined. It was shown that a fast PMT could be used in alpha particle detection in addition to the timing measurement. With this study, a Hamamatsu R18128-01 type PMT was first tested for the alpha detection and the detection performances through the main amplifiers were compared. [ABSTRACT FROM AUTHOR]

Recent progress in the field of scintillators and silicon photomultipliers (SiPM) has allowed development of new scintillation detectors capable of detecting low-energy X- and gamma-ray sources that are widely used in medicine, security and industry. Such scintillation detectors are compact, insensitive to magnetic fields, have low operation voltages and are functional at room temperature. These advantages of SiPM are considered to solve the main problems facing scintillation detectors in medicine and industry today. Development of detectors of low-energy electromagnetic radiation is relevant now. Scintillation detectors based on lutetium fine silicate, LaBr3(Ce), NaI and silicon avalanche photomultipliers offer a great potential for use for X- and gamma-ray detection. The present work demonstrates the gamma-ray detection performance of a new micropixel avalanche photodiode (MAPD) array (16 (4×4) elements - 15×15 cm) with a LaBr3(Ce) scintillator (15×15×30 mm) using 177Lu and 133Ba isotopes as the gamma-ray sources. [ABSTRACT FROM AUTHOR]

BACKGROUND: X-ray micro-tomography (μCT) is a powerful non-destructive 3D imaging method applied in many scientific fields. In combination with propagation-based phase-contrast, the method is suitable for samples with low absorption contrast. Phase contrast tomography has become available in the lab with the ongoing development of micro-focused tube sources, but it requires sensitive and high-resolution X-ray detectors. The development of novel scintillation detectors, particularly for microscopy, requires more flexibility than available in commercial tomography systems. OBJECTIVE: We aim to develop a compact, flexible, and versatile μCT laboratory setup that combines absorption and phase contrast imaging as well as the option to use it for scintillator characterization. Here, we present details on the design and implementation of the setup. METHODS: We used the setup for μCT in absorption and propagation-based phase-contrast mode, as well as to study a perovskite scintillator. RESULTS: We show the 2D and 3D performance in absorption and phase contrast mode, as well as how the setup can be used for testing new scintillator materials in a realistic imaging environment. A spatial resolution of around 1.3μm is measured in 2D and 3D. CONCLUSIONS: The setup meets the needs for common absorption μCT applications and offers increased contrast in phase contrast mode. The availability of a versatile laboratory μCT setup allows not only for easy access to tomographic measurements, but also enables a prompt monitoring and feedback beneficial for advances in scintillator fabrication. [ABSTRACT FROM AUTHOR]

The characteristics of a Silicon Photo Multiplier (SiPM)-based scintillation detector system were studied. The influence of the bias voltage and the number of SiPMs on the energy resolution was identified. The single SiPM energy spectra in the multi-SiPM system showed their dependency on the position of the 60Co radiation source. The application of geometric mean on the multi-SiPM system was also considered to bypass single channel calibrations. Preliminary results on the performances of developing scintillation detectors with a CsI(Tl) crystal or a plastic scintillator are demonstrated. The capability of charged particle measurement for CsI(Tl) crystal and sub-nanosecond timing resolution of plastic scintillator were identified. [ABSTRACT FROM AUTHOR]

The Nd-doped LaMgAl11O19 single crystals were synthesized by the floating zone method, and the photoluminescence and scintillation properties were evaluated. Under X-ray irradiation, several sharp emission peaks due to the 4f–4f transitions of Nd3+ were observed at 900, 1060, and 1340 nm in the near-infrared range, and the decay curves show the typical decay time for Nd3+. The samples show good afterglow properties comparable with practical X-ray scintillators. The 1% and 3% Nd-doped LaMgAl11O19 samples show a good linearity in the dynamic range from 6–60,000 mGy/h. [ABSTRACT FROM AUTHOR]

We present here a characterization of the low background NaI(Tl) crystal NaI-33 based on a period of almost one year of data taking (891 kg × days exposure) in a detector configuration with no use of organic scintillator veto. This remarkably radio-pure crystal already showed a low background in the SABRE Proof-of-Principle (PoP) detector, in the low energy region of interest (1–6 keV) for the search of dark matter interaction via the annual modulation signature. As the vetoable background components, such as 40 K, are here sub-dominant, we reassembled the PoP setup with a fully passive shielding. We upgraded the selection of events based on a Boosted Decision Tree algorithm that rejects most of the PMT-induced noise while retaining scintillation signals with > 90% efficiency in 1–6 keV. We find an average background of 1.39 ± 0.02 counts/day/kg/keV in the region of interest and a spectrum consistent with data previously acquired in the PoP setup, where the external veto background suppression was in place. Our background model indicates that the dominant background component is due to decays of 210 Pb, only partly residing in the crystal itself. The other location of 210 Pb is the reflector foil that wraps the crystal. We now proceed to design the experimental setup for the physics phase of the SABRE North detector, based on an array of similar crystals, using a low radioactivity PTFE reflector and further improving the passive shielding strategy, in compliance with the new safety and environmental requirements of Laboratori Nazionali del Gran Sasso. [ABSTRACT FROM AUTHOR]

Liquid xenon time projection chambers are promising detectors to search for neutrinoless double beta decay (0 ν β β ), due to their response uniformity, monolithic sensitive volume, scalability to large target masses, and suitability for extremely low background operations. The nEXO collaboration has designed a tonne-scale time projection chamber that aims to search for 0 ν β β of 136 Xe with projected half-life sensitivity of 1.35 × 10 28 yr. To reach this sensitivity, the design goal for nEXO is ≤ 1% energy resolution at the decay Q-value ( 2458.07 ± 0.31 keV). Reaching this resolution requires the efficient collection of both the ionization and scintillation produced in the detector. The nEXO design employs Silicon Photo-Multipliers (SiPMs) to detect the vacuum ultra-violet, 175 nm scintillation light of liquid xenon. This paper reports on the characterization of the newest vacuum ultra-violet sensitive Fondazione Bruno Kessler VUVHD3 SiPMs specifically designed for nEXO, as well as new measurements on new test samples of previously characterised Hamamatsu VUV4 Multi Pixel Photon Counters (MPPCs). Various SiPM and MPPC parameters, such as dark noise, gain, direct crosstalk, correlated avalanches and photon detection efficiency were measured as a function of the applied over voltage and wavelength at liquid xenon temperature (163 K). The results from this study are used to provide updated estimates of the achievable energy resolution at the decay Q-value for the nEXO design. [ABSTRACT FROM AUTHOR]

This presentation examines the energetic particle transport induced by saturated kink modes and sawtooth crashes in JET deuterium plasmas. It is known that kink mode-resonant transport and phase-space redistribution from sawtooth crashes can drive strong fast ion transport with dependencies on particle pitch and energy. Measurements with JET’s Faraday cup fast ion loss detector array have shown that the internal kink growth phase preceding sawtooth crashes produces substantial fast ion losses. This report will numerically investigate the dominant energetic particle transport mechanism with a detailed examination of the fast ion phase-space dependencies, resonances, orbit topology changes, induced losses, and redistribution associated with the long-lived, resonant, kink mode and non-resonant sawtooth crash. The ORBIT-kick model forms the basis of the transport studies with realistic fast ion distributions produced from TRANSP. A recently created reduced model for sawtooth induced transport is used while the saturated kink modes are modeled with ideal magnetohydrodynamic codes. The simulations were further validated against experiment with a newly developed synthetic Faraday cup fast ion loss detector in addition to scintillator probe and neutron measurements. [ABSTRACT FROM AUTHOR]