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We report the photon (PL), electron (CL) and X-ray (XEL) induced luminescence characteristics of high aspect ratio ultra-long (~ 50 µm) ZnO nanorods (NRs) and discuss the potential for fast X-ray detection based on the consistent and efficient visible emission (~ 580 nm) from ZnO NRs. Nanostructured ZnO scintillators were rearranged to form a vertically well-aligned NR design in order to help light absorption and coupling resulting in luminescent and fast scintillation properties. The design of the nanorod array combines the key advantages of a low-cost growth technique together with environmentally friendly and widely available materials. A low temperature hydrothermal method was adopted to grow ZnO NRs in one cycle growth and their structural, optical and X-ray scintillation properties were investigated. The relatively short (~ 10 µm) ZnO NRs emitting in the near-band-edge region were found to be almost insensitive to X-rays. On the other hand, the higher XEL response of long ZnO NRs, which is a key parameter for evaluation of materials to be used as scintillators for high quality X-ray detection and imaging, along with a decay time response in the order of ns confirmed promising scintillation properties for fast and high-resolution X-ray detector applications. [ABSTRACT FROM AUTHOR]

Novel scintillating and visualizing materials are an essential part of the development of high-power X-ray sources like synchrotrons and free-electron lasers. One of the latest approaches is the formation of composite materials composed of X-ray luminescent nanoparticles in a robust transparent matrix with high thermal conductivity. Here, such Sr 0.85-x Ba x Eu 0.15 F 2.15 nanopowders with a particle size of ≈50 nm were synthesized by precipitation from aqueous solutions. Single-phase solid solutions are formed up to a barium concentration of 70 mol.%. The most intense luminescence band is the band of trivalent europium with a maximum at 590.4 nm, corresponding to the 5D 0 → 7F 1 transition. The concentration dependence of the X-ray luminescence intensity on the barium content was revealed, and the most optimal composition Sr 0.35 Ba 0.50 Eu 0.15 F 2.15 with the brightest luminescence response was determined. The obtained type of nanoparticles has potential applications for the fabrication of new scintillating and visualizing composites. [ABSTRACT FROM AUTHOR]

X‐ray induced photodynamic therapy (X‐PDT) circumvents the poor penetration depth of conventional PDT with minimal radio‐resistance generation. However, conventional X‐PDT typically requires inorganic scintillators as energy transducers to excite neighboring photosensitizers (PSs) to generate reactive oxygen species (ROS). Herein, a pure organic aggregation‐induced emission (AIE) nanoscintillator (TBDCR NPs) that can massively generate both type I and type II ROS under direct X‐ray irradiation is reported for hypoxia‐tolerant X‐PDT. Heteroatoms are introduced to enhance X‐ray harvesting and ROS generation ability, and AIE‐active TBDCR exhibits aggregation‐enhanced ROS especially less oxygen‐dependent hydroxyl radical (HO•−, type I) generation ability. TBDCR NPs with a distinctive PEG crystalline shell to provide a rigid intraparticle microenvironment show further enhanced ROS generation. Intriguingly, TBDCR NPs show bright near‐infrared fluorescence and massive singlet oxygen and HO•− generation under direct X‐ray irradiation, which demonstrate excellent antitumor X‐PDT performance both in vitro and in vivo. To the best of knowledge, this is the first pure organic PS capable of generating both 1O2 and radicals (HO•−) in response to direct X‐ray irradiation, which shall provide new insights for designing organic scintillators with excellent X‐ray harvesting and predominant free radical generation for efficient X‐PDT. [ABSTRACT FROM AUTHOR]

Undoped, 0.5, 1.0, and 2.0% Nd-doped Bi4Si3O12 (BSO) crystals were synthesized by the floating zone method. Regarding photoluminescence (PL) properties, all samples had emission peaks due to the 6p–6s transitions of Bi3+ ions. In addition, the Nd-doped samples had emission peaks due to the 4f–4f transitions of Nd3+ ions as well. The PL quantum yield of the 0.5, 1.0, and 2.0% Nd-doped samples in the near-infrared range were 67.9, 73.0, and 56.6%, respectively. Regarding X-ray-induced scintillation properties, all samples showed emission properties similar to PL. Afterglow levels at 20 ms after X-ray irradiation of the undoped, 0.5, 1.0, and 2.0% Nd-doped samples were 192.3, 205.9, 228.2, and 315.4 ppm, respectively. Dose rate response functions had good linearity from 0.006 to 60 Gy/h for the 1.0% Nd-doped BSO sample and from 0.03 to 60 Gy/h for the other samples. [ABSTRACT FROM AUTHOR]

The ability of a scintillator to absorb and convert the high-energy X-ray photons to low-energy visible photons is crucial for the application of X-ray in medical tests, security checks and scientific research. However, traditional scintillation crystals are synthesized by complex preparation process with high cost, hindering the wide development in practical applications. Here, Tb3+ doped sodium silicate glass, which exhibits remarkable scintillation property and recoverability to X-ray irradiation, was successfully prepared by an exercisable melt-quenching method. The obtained scintillator shows intense radioluminescence, which is about 1.5 times higher than that of the reference of Bi 4 Ge 3 O 12. The damaged glass to X-ray irradiation can be returned to the original state after heat treatment again, indicating excellent recovery. Moreover, the scintillator displays wonderful thermal stability with the fluorescence intensity at 573 K still remaining 96% at room temperature. These results demonstrate that the obtained scintillating glass has potential application towards the real world. [ABSTRACT FROM AUTHOR]

The article presents the discussion on advancement in consumer electronics and high performance requirements for emerging applications. Topics include internet of things (IOT), self-driving cars, artificial intelligence (AI), and 5G propelling new heterogeneous integration packages; and X-ray imaging being one of the primary nondestructive analysis methods for electronic packages and printed circuit boards (PCBs).

lthough single crystal scintillators have excellent performance, they have some drawbacks such as high cost, complicated elaboration method and difficulty of growth on large-scale. Glass scintillators are widely investigated to replace single crystal scintillators because of their simple fabrication method and low cost. In this paper, a series of transparent borosilicate aluminate glass scintillators doped with Tb3+ were successfully prepared by traditional melt-quenching method. The structural, luminescent, and X-ray excited scintillating properties were investigated. These glass samples show high stability and high transparency, and present good luminescent and scintillating properties. Sample with Tb3+ doping concentration of 10% has the best scintillating performance. The integrated intensity of X-ray excited luminescence is 66.6% of that of commercial Bi 4 Ge 3 O 12 single crystal scintillator, and the quantum efficiency (under 378 nm excitation) is 70.3%. Our findings suggest that Tb3+-doped borosilicate aluminate glasses with high light yield might be used as potential scintillators. [ABSTRACT FROM AUTHOR]

Temperature dependence of the luminescence characteristics of Lu1.84Y0.16SiO5:Ce (LYSO:Ce) scintillator was investigated under x-ray excitation. The luminescence decay time, light yield, radioluminescence (RL) spectra, spatial resolution, and luminescence homogeneity from 300 to 550 K are experimentally examined with multiple x-ray facilities. The results show that the decay time and light output of the LYSO:Ce scintillator will decrease from 42 to 1.89 ns and from 32 000 to 1120 photons/MeV with a temperature increase from 300 to 550 K, respectively. The RL spectrum experiments demonstrate that the spectrum peak will move from 414 to 426 nm when adjusting the temperature from 300 to 550 K. The spatial resolution experiments show that the spatial resolution is hardly affected and can reach as high as 2.5 lp/mm when increasing the temperature from 300 to 550 K, and the luminescence homogeneity remains unchanged with increase in temperature. The experimental results provide important information for the radiation imaging application of the LYSO:Ce scintillator. [ABSTRACT FROM AUTHOR]

We present the design and characterization of an X-ray imaging system consisting of an off-the-shelf CMOS sensor optically coupled to a CsI scintillator. The camera can perform both high-resolution and functional cardiac imaging. High-resolution 3D imaging requires microfocus X-ray tubes and expensive detectors, while pre-clinical functional cardiac imaging requires high flux pulsed (clinical) X-ray tubes and high-end cameras. Our work describes an X-ray camera, namely an "optically coupled X-ray(OCX) detector," used for both the aforementioned applications with no change in the specifications. We constructed the imaging detector with two different CMOS optical imaging cameras called CMOS sensors, 1.A monochrome CMOS sensor coupled with an f1.4 lens and 2.an RGB CMOS sensor coupled with an f0.95 prime lens. The imaging system consisted of our X-ray camera, micro-focus X-ray source (50kVp and 1mA), and a rotary stage controlled from a personal computer (PC) and LabVIEW interface. The detective quantum efficiency (DQE) of the imaging system(monochrome) estimated using a cascaded linear model was 17% at 10 lp/mm. The system modulation transfer function (MTF) and the noise power spectrum (NPS) were inputs to the DQE estimation. Because of the RGB camera's low quantum efficiency (QE), the OCX detector DQE was 19% at 5 lp/mm. The contrast to noise ratio (CNR) at different frame rates was studied using the capillary tubes filled with various dilutions of iodinated contrast agents. In-vivo cardiac angiography demonstrated that blood vessels of the order of 100 microns or above were visible at 40 frames per second despite the low X-ray flux. For high-resolution 3D imaging, the system was characterized by imaging a cylindrical micro-CT contrast phantom and comparing it against images from a commercial scanner. [ABSTRACT FROM AUTHOR]

X-ray radiography is the most widely used imaging technique with applications encompassing medical and industrial imaging, homeland security, and materials research. Although a significant amount of research and development has gone into improving the spatial resolution of the current state-of-the-art indirect X-ray detectors, it is still limited by the detector thickness and microcolumnar structure quality. This paper demonstrates high spatial resolution X-ray imaging with solution-processable two-dimensional hybrid perovskite single-crystal scintillators grown inside microcapillary channels as small as 20 µm. These highly scalable non-hygroscopic detectors demonstrate excellent spatial resolution similar to the direct X-ray detectors. X-ray imaging results of a camera constructed using this scintillator show Modulation Transfer Function values significantly better than the current state-of-the-art X-ray detectors. These structured detectors open up a new era of low-cost large-area ultrahigh spatial resolution high frame rate X-ray imaging with numerous applications. [ABSTRACT FROM AUTHOR]

X-ray luminescent diamond composite films with embedded yttrium-aluminum nanoparticles were designed. Additionally, the stability limits of single-phase solid solutions in systems based on yttrium-aluminum and yttrium-scandium-aluminum garnets doped with cerium were determined. The most intense X-ray luminescence was achieved with the [Y 2·98 Ce 0.02 ]{Al 2 }Al 3 O 12 powder. The composition-optimized nanoparticles were embedded into a polycrystalline diamond matrix to form a diamond-YAG:Ce composite. For the obtained composite, an intense X-ray luminescence from the Ce3+ ions near 550 nm was demonstrated. The designed composites may be used as adjustable and durable scintillating materials for a wide range of applications. [ABSTRACT FROM AUTHOR]

The low-energy ultraviolet or visible photons can be produced by the interaction between the scintillator materials and ionizing radiation. For this reason, scintillator materials are widely used as radiation detectors, which are prevalently utilized in different applications such as nuclear medicine imaging, homeland security, high-energy physics, oil drilling explorations, etc. Herein, a high-atomic-number (Z) zirconium-based metal-organic framework nanoflower material CJLU-1 (Zr 6 (μ 3 -O) 4 (μ 3 -OH) 4 (OH) 6 (TCA) 2 (H 2 O) 6) (H 3 TCA = tri-carboxylic acids 4,4′,4″-nitrilotribenzoic acid) was synthesized and can effectively convert X-ray into visible light. CJLU-1 is composed of secondary structural unit hexagonal Zr metal cluster and connected by TCA ligands. The photo luminescence spectra (PL) emission peak and excitation peak of CJLU-1 are at 470 nm and 395 nm respectively. CJLU-1 exhibited radioluminescence (RL) peak with a maximum at 480 nm under steady-state excitation with X-rays. Moreover, by accommodating different guest molecules such as xylene and RhB in the same MOF material, intensity-tunable X-ray scintillation can be facilely achieved, providing a new class of scintillating materials with luminescence intensity tunability. The high-Z hexagonal Zr clusters, which are arranged in an orderly fashion, absorb and interact with the ionizing radiation and sensitize the adjacent organic ligands TCA to produce efficient RL. This work contributes to the development of high-Z zirconium-based MOFs and RL intensity-tunable scintillation materials towards future practical nuclear sensing applications. A high-atomic-number (Z) zirconium-based metal-organic framework nanoflower material CJLU-1 was synthesized and can effectively convert X-ray into visible light. [Display omitted] • A zirconium-based MOF was constructed and realized tunable radioluminescence upon accommodation of guest molecules. [ABSTRACT FROM AUTHOR]

Indirect flat panel detectors (I‐FPDs) enable digital radiography at high X‐ray energies. However, the performance of these devices is limited due to the large number of X rays that pass through them undetected. The authors hypothesize that a glass‐based scintillator may serve as a substrate for the thin film transistors and photodiodes in an I‐FPD, leading to improvements in X‐ray detection for improved performance. The authors synthesized a series of five glass‐ceramic scintillators based on an oxyhalide glass matrix. Each glass ceramic contains barium chloride crystals which serve as scattering centers to prevent "light trapping" in the material; barium chloride is also a well‐known scintillation crystal. Four of the samples contain trivalent terbium, which serves as a second luminescent center. The light output of each sample was compared against a well‐known X‐ray scintillator, gadolinium oxysulfide (GOS) under RQA9 exposure conditions, in the back‐irradiation configuration. The addition of terbium oxide to the glass composition increases the detected light output, which varies by concentration. The thickness of the glass‐ceramic scintillator has a profound effect on performance, with the results influenced by such factors as self‐attenuation of emission in the thicker samples and decreased X‐ray capture in the thinner samples. The brightest sample tested achieved a light output 13% that of the GOS intensifier screen. The results indicate that the use of scintillating glass‐ceramic substrates should lead to increased performance in indirect digital radiography. [ABSTRACT FROM AUTHOR]

Propagation-based phase-contrast X-ray computed tomography is a valuable tool for high-resolution visualization of biological samples, giving distinct improvements in terms of contrast and dose requirements compared to conventional attenuation-based computed tomography. Due to its ease of implementation and advances in laboratory X-ray sources, this imaging technique is increasingly being transferred from synchrotron facilities to laboratory environments. This however poses additional challenges, such as the limited spatial coherence and flux of laboratory sources, resulting in worse resolution and higher noise levels. Here we extend a previously developed iterative reconstruction algorithm for this imaging technique to include models for the reduced spatial coherence and the signal spreading of efficient scintillator-based detectors directly into the physical forward model. Furthermore, we employ a noise model which accounts for the full covariance statistics of the image formation process. In addition, we extend the model describing the interference effects such that it now matches the formalism of the widely-used single-material phase-retrieval algorithm, which is based on the sample-homogeneity assumption. We perform a simulation study as well as an experimental study at a laboratory inverse Compton source and compare our approach to the conventional analytical approaches. We find that the modeling of the source and the detector inside the physical forward model can tremendously improve the resolution at matched noise levels and that the modeling of the covariance statistics reduces overshoots (i.e. incorrect increase / decrease in sample properties) at the sample edges significantly. [ABSTRACT FROM AUTHOR]

Commercial Bi4Ge3O12 (BGO) monocrystal scintillator is relatively complicated to produce and too expensive. Therefore, it is desired to look for alternative scintillating materials with simple process, low consumption, large size, and high efficiency. Here, glass‐ceramics (GC) with high volume fraction of crystal phase and high density by increasing the proportion of heavy metal fluorides in the composition were designed. And bulk Tb3+‐doped transparent BaGdF5 glass‐ceramics with 23.3% crystal volume ratio and density of 4.65 g/cm3 have been prepared. The structural, optical, and luminescent properties of precursor glass and GC were systematically explored through series of characterization techniques including X‐ray diffraction (XRD), transmittance spectra, transmission electron microscope (TEM), photoluminescence (PL) spectra, and X‐ray excited luminescence (XEL). After heat treatment, both PL emission and XEL intensity of GC are enhanced because of the movement of Tb3+ ions from the amorphous glass matrix into BaGdF5 nanocrystals, which possess lower phonon energy and better crystal field. The luminescent quantum efficiency of GC reaches 30.7% and the XEL intensity of GC is around 140% of that of the commercial BGO scintillating crystal. Our results demonstrate that BaGdF5:Tb3+ GC may act as efficient scintillator for X‐ray detection. [ABSTRACT FROM AUTHOR]

Mg 4 Ta 2 O 9 :x at % M (M = Hf4+, Zr4+, W6+, Mo6+; x = 0, 1, 2, 3, 4, 5) with single phase were synthesized via the conventional solid-state reactions in air. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), vacuum ultraviolet (VUV) light excited spectra and X-rays excited luminescence (XEL). Structural characterization and Rietveld refinement show that more than 60% of 5 at % Hf4+, Zr4+, W6+ and Mo6+ doped ions enter into the Ta sites and less than 40% ions into the Mg(1) and Mg(2) sites. They can be excited efficiently by VUV light at 160 nm, and emit wide UV-A or blue light at 355∼458 nm depending on the doping ion and its concentration. XEL spectra and decay time data indicate that Mg 4 Ta 2 O 9 :1 at % Hf4+ has excellent X-ray excited scintillation performance typically with light yield of 13469 ph/MeV and decay time of 5.28 μs. Thus, it has potential application in optical conversion devices and security inspection. Mg 4 Ta 2 O 9 :x at % M (M = Hf4+, Zr4+, W6+, Mo6+; x = 0, 1, 2, 3, 4, 5) with single phase were synthesized via the conventional solid-state reactions in air. The SEM images of MTO: Hf4+ with the corresponding elemental EDX analysis indicate that the powder shape is irregular and the elements of Mg, Ta, O and Hf disperse homogeneously on the particles. The VUV light excited and X-ray excited luminescence performance indicate it has potential application in optical conversion devices and security inspection. [Display omitted] • Mg 4 Ta 2 O 9 : x at% M (M = Hf4+, Zr4+, W6+, Mo6+; x = 0, 1, 2, 3, 4, 5) powders were synthesized. • The photoluminescence, X-ray excited radio-luminescence and decay times are characterized. • MTO doped by 2 at % Hf4+ / Zr4+ and 1 at % W6+ / Mo6+ have the decay time of 5.28 μs, 5.60 μs, 3.70 μs, 4.16 μs, respectively. • The main excitation peak of photoluminescence is at 160 nm instead of about 220 nm reported. • Mg 4 Ta 2 O 9 :1 at % Hf4+ has excellent X-ray excited scintillation performance typically with light yield 13469 ph/MeV. [ABSTRACT FROM AUTHOR]

The paper describes an original technique for non-contact in situ monitoring of the temperature developed for experiments in a vacuum environment at the tender X-ray beamline I23 of the Diamond Light Source. The sample temperature is established by determining the luminescence decay constant of a Bi4Ge3O12 (BGO) scintillation sensor. BGO is ideally suited for a temperature range of 30 K to 130 K, in which its decay constant shows a strong temperature dependence. The principle of the method, system design and application examples are discussed and the performance and potential of the technique is assessed. [ABSTRACT FROM AUTHOR]

A low-cost multi-channel analyzer (MCA) system was developed using a custom-build interface circuit and a PC sound card. The performance of the system was studied using γ-ray spectroscopy measurements with a NaI(Tl) scintillation detector. Our system successfully measured the energy of γ-rays at a rate of 1000 counts per second (cps). [ABSTRACT FROM AUTHOR]

Lu3Al5O12(LuAG) dopedwith Ce3 a promising scintillator material with a highdensityand a fast response time. The light output under X-ray or γ-rayexcitation is, however, well below the theoretical limit. In thispaper the influence of codoping with Tb3 investigatedwith the aim to increase the light output. High resolution spectraof singly doped LuAG (with Ce3 Tb3) arereported and provide insight into the energy level structure of thetwo ions in LuAG. For Ce3췪phonon lines and vibronicstructure are observed for the two lowest energy 5d bands and theStokes’ shift (2 350 cm–1) and Huang–Rhyscoupling parameter (S= 9) have been determined.Tb3–5d transitions to the high spin (HS) andlow spin (LS) states are observed (including a zero-phonon line andvibrational structure for the high spin state). The HS–LS splittingof 5400 cm–1is smaller than usually observed andis explained by a reduction of the 5d–4f exchange couplingparameter Jby covalency. Upon replacing the smallerLu3誉 with the larger Tb3誉, the crystalfield splitting for the lowest 5d states increases, causing the lowest5d state to shift below the 5D4state of Tb3橷 allowing for efficient energy transfer from Tb3 Ce3皌 to the lowest temperatures. Luminescencedecay measurements confirm efficient energy transfer from Tb3 Ce3橷 provide a qualitative understanding of theenergy transfer process. Co-doping with Tb3皇 not resultin the desired increase in light output, and an explanation basedon electron trapping in defects is discussed. [ABSTRACT FROM AUTHOR]

The article presents a study which measures the decay time and weak afterglow of scintillation from YAG:Ce3+ using a high-speed complementary metal oxide semiconductors (CMOS) camera and pulsed X-rays. It also examines the positional variance of the X-ray beam in isolated bunches. It states that the possibility of an X-ray diffraction study at high time and space resolution is shown in the results.

The efficiency of high-resolution pixel detectors for hard X-rays is nowadays one of the major criteria which drives the feasibility of imaging experiments and in general the performance of an experimental station for synchrotron-based microtomography and radiography. Here the luminescent screen used for the indirect detection is focused on in order to increase the detective quantum efficiency: a novel scintillator based on doped Lu2SiO5 (LSO), epitaxially grown as thin film via the liquid phase epitaxy technique. It is shown that, by using adapted growth and doping parameters as well as a dedicated substrate, the scintillation behaviour of a LSO-based thin crystal together with the high stopping power of the material allows for high-performance indirect X-ray detection. In detail, the conversion efficiency, the radioluminescence spectra, the optical absorption spectra under UV/visible-light and the afterglow are investigated. A set-up to study the effect of the thin-film scintillator's temperature on its conversion efficiency is described as well. It delivers knowledge which is important when working with higher photon flux densities and the corresponding high heat load on the material. Additionally, X-ray imaging systems based on different diffraction-limited visible-light optics and CCD cameras using among others LSO-based thin film are compared. Finally, the performance of the LSO thin film is illustrated by imaging a honey bee leg, demonstrating the value of efficient high-resolution computed tomography for life sciences [ABSTRACT FROM AUTHOR]

Comparatively high gadolinium contents are of primary importance for (Y,Gd)2O3:Eu scintillators because of expected higher scintillation intensity and higher light output of the materials. Transparent Y0.6Gd1.34Eu0.06O3 ceramic, with a high gadolinium composition of ∼67 mol%, has been fabricated via vacuum sintering using synthesized sinterable powders. The precursor powder was coprecipitated with ammonium hydrogen carbonate as the precipitant and the powder calcined at 1100°C showed the best sintering activity. Transparent Y0.6Gd1.34Eu0.06O3 ceramic, exhibiting an in-line transmittance of 66.7% at 610 nm, was obtained by vacuum sintering at 1670°C for 2 h. Under X-ray excitation, the ceramic exhibited characteristic emissions of the Eu3+ ions. [ABSTRACT FROM AUTHOR]

Neutrons from deuteron-deuteron fusion reactions were used for the study of pinch dynamics in a modified small plasma-focus device at a current peak of 200 kA. In front of the inner electrode (anode), an antielectrode was placed. Neutron yield reached 105 - 107 per shot. The time-resolved neutron signals were registered with two scintillation detectors positioned end-on and side-on at the same distance of 150 cm from the interelectrode gap. They enabled the comparison of difference in energies and estimation of directions of fast deuterons producing neutrons. The XUV frames imaged the pinch configuration at the moment of X-ray and neutron emission and differed in shots with high and low neutron yields. Interferograms enabled the evaluation of distribution of plasma density. The presence of the antianode decreased the neutron yield and influenced the distribution of the plasma density in front of the anode. [ABSTRACT FROM AUTHOR]

We have studied the effect of lead dopant on the optical absorption, photoluminescence, and x-ray luminescence spectra, and the scintillation characteristics of CdI2 at room temperature. The crystals for the study were grown by the Stockbarger-Bridgman method. Activation of CdI2 from the melt by the compound PbI2 leads to the appearance in the absorption spectra in the near-edge region of an activator band at 395–405 nm, which is interpreted as an A band connected with electronic transitions from the 1S0 state to the 3P1 levels in the Pb2+ ion. For x-ray excitation, CdI2:Pb2+ crystals with optimal dopant concentration (∼1.0 mol%) are characterized by a light yield with maximum in the 570–580 nm region that is an order of magnitude higher than for CdI2 crystals in the 490–500 nm band. For α excitation, the radioluminescence kinetics for cadmium iodide is characterized by a very short (∼0.3 nsec) rise time and fast decay of luminescence, with τ1 ≈ 4 nsec and τ2 = 10–76 nsec. Depending on the conditions under which the crystals were obtained, the fast component fraction is 95%–99%. The crystal is characterized by a similar scintillation pulse in the case of excitation by x-ray pulses. The radioluminescence pulse shape for CdI2:Pb in the decay stage is predominantly exponential, with luminescence decay time constants τ1 ≈ 10 nsec and τ2 = 200–250 nsec. This system is characterized by low afterglow, at the level for the Bi4G3O12 scintillator. We have demonstrated the feasibility of using CdI2:Pb as a scintillator for detecting α particles. [ABSTRACT FROM AUTHOR]

A three-dimensional X-ray detector for imaging 30-200 keV photons is described. It comprises a set of semi-transparent structured scintillators, where each scintillator is a regular array of waveguides in silicon, and with pores filled with CsI. The performance of the detector is described theoretically and explored in detail through simulations. Based on available hardware, a spatial resolution of 1 µm is obtainable. The resolution of a single screen is shown to be determined only by the pitch, at least up to 100 keV. In comparison with conventional homogeneous screens, an improvement in efficiency by a factor of 5-15 is obtainable. The cross-talk between screens in the three-dimensional detector is shown to be negligible. The three-dimensional concept enables ray- tracing and super-resolution algorithms to be applied. [ABSTRACT FROM AUTHOR]

The effective use of near water equivalent organic plastic scintillators (OPS) for radiation dosimetry with high-energy sources under laboratory conditions is recognized. In this work, an OPS-based dosimeter using a photodiode combined with improved solid state detection and signal processing techniques has been developed; it offers the potential for the construction of a stable and fully portable dosimeter which will extend the useful range of measurement beyond the usual MeV area and provide reliable readings down to sub-'100 keV' X-ray energy levels. In these experiments, the instrument described has been used for the dosimetry of INTRABEAM intraoperative radiotherapy (IORT) equipment at distances as low as 1.8 mm from the effective source, i.e., 0.2 mm from the X-ray probe surface. Comparison is shown with dosimetry measurements made using the calibrated reference ion chamber supplied by the IORT equipment manufacturer. [ABSTRACT FROM AUTHOR]

The development of scintillating materials is believed to reach a new step by controlling their preparation on a nanometric level. Sol-Gel chemistry offers very unique tools for nanoscale mastering of the materials preparation. In particular, shaping of the materials as thin films or nanoparticles offers new application in medical imaging. The control of doping ions dispersion thanks to soft chemistry is also a great advantage of such synthetic routes. In this paper, we will review recent work devoted to the sol-gel preparation of inorganic scintillating materials.We will focus on the new possibilities and advantages offered by sol-gel chemistry for the preparation of new scintillators and improvement of existing ones. [ABSTRACT FROM AUTHOR]

We have investigated the potential use of Bi4Ge3O12 (BGO) laser-sintered ceramics in scintillator devices for radiation detection. Relevant results from the characterization made during the ceramic processing are presented, such as particle size analysis, X-ray diffraction studies, and thermal analysis. Furthermore, we have compared the microstructure, relative density, thermoluminescent (TL) emission, and transparency degree of ceramic bodies sintered by CO2 laser heating with a reference set of ceramics sintered in an electrical furnace, and also with single crystals grown by the Czochralski technique. It was observed that the laser-sintered BGO presented a relative density of 98% (±2%), better pore shrinkage, larger grains, and light transmission intensity 1.5 times higher than the BGO ceramics sintered in a furnace. The TL curves of all samples irradiated with UV and β—rays presented peaks at 75°, 102°, and 143°C, and provided strong indication that the intergrain defects have the same nature of the bulk defects and do not contribute with new traps in the temperature range studied. The relative areas of the total TL emission after IS irradiation were 6,0:4,4:1 for the reference ceramic, laser sintered ceramic, and single crystal, respectively. For UV irradiated samples, this relation was 7,1:4,7:1. From these results, we have concluded that laser-sintered ceramics have an amount of charge traps lower than the conventionally sintered BGO samples, thus having a higher radioluminescence yield. [ABSTRACT FROM AUTHOR]

• Glasses in the system NaPO 3 -Ba(PO 3) 2 -MgF 2 -YF 3 doped with EuF 3 (x = 0.0-4.0 mol%) or Dy 2 O 3 (x = 0.0-1.0 mol%) were investigated as high energy sensors. • The glasses present excellent optical quality up to the dispersion level of 4.0 mol% Eu3+ and at least up to 1.0 mol% Dy3+. • No sign of photoluminescence or radioluminescence intensity saturation was observed for the highest RE activator concentration suggesting that higher RE activator concentrations could lead to still higher luminous output. • Photoluminescence spectra measured under varying excitation powers at 365 nm allow construction of calibration curves that can be used to quantitatively detect the UV radiation. • Luminescence and excited state lifetime values indicate the glasses are promising candidates for glass scintillators for X-ray detection. In this work, fluorophosphate glass samples with the composition 35NaPO 3 -30Ba(PO 3) 2 -25MgF 2 -(10- x)YF 3 –x[EuF 3 or Dy 2 O 3 ] with x = 0–4.0 mol% EuF 3 , or x = 0–1.0 mol% Dy 2 O 3 , were fabricated by the melt quenching technique. The glasses were characterized from the structural, thermal and optical-spectroscopic points of view. Emission spectra were measured in the visible range upon UV excitation. Luminescence decay curves were registered by monitoring the most intense emissions of Eu3+ (5D 0 →7F 2) and of Dy3+ (4F 9/2 →6H 13/2) in the red and green, respectively, and from them the average lifetime values of the excited states 5D 0 of Eu3+ (2.5 ms) and 4F 9/2 of Dy3+ (0.71 ms) were determined. Emission spectra measured under variable excitation power yielded calibration curves for Eu3+ and Dy3+-doped glasses. The response to X-ray excitation was evaluated through radioluminescence measurements. The results indicate the promising application of these glasses in scintillators and for X-ray sensing devices. [ABSTRACT FROM AUTHOR]

Certain imaging performance metrics are examined for a state-of-the-art 20 μm pixel pitch CMOS sensor (RadEye HR), coupled to a Gd2O2S:Tb scintillator screen. The signal transfer property (STP), the modulation transfer function (MTF), the normalized noise power spectrum (NNPS) and the detective quantum efficiency (DQE) were estimated according to the IEC 62220-1-1:2015 standard. The detector exhibits excellent linearity (coefficient of determination of the STP linear regression fit, R2 was 0.9978), while its DQE peaks at 33% and reaches 10% at a spatial frequency of 3 cycles/mm, for the measured with a Piranha RTI dosimeter (coefficient of variation CV = 0.03%) exposure value of 28.1 μGy DAK (detector Air Kerma). The resolution capabilities of the X-ray detector under investigation were compared to other commercial CMOS sensors, and were found in every case higher, except from the previous RadEye HR model (CMOS—Gd2O2S:Tb screen pair with 22.5 μm pixel pitch) version which had slightly better MTF. The present digital imager is designed for industrial inspection applications, nonetheless its applicability to medical imaging, as well as dual-energy is considered and certain approaches are discussed in this respect. [ABSTRACT FROM AUTHOR]

Lutetium pyrosilicate (Lu 2 Si 2 O 7) single crystals were synthesized by using the floating-zone method with 0.1, 0.5, 1.0, 2.0 and 5.0% of Tm-doping concentration. After the phase confirmation by powder XRD, photoluminescence (PL) and scintillation properties were systematically measured, including PL emission map, PL decay time, scintillation spectra, scintillation decay time and pulse height spectra. When we irradiated X-rays, we observed the scintillation emission at 360 and 460 nm caused by Tm3+ 4f-4f transitions. Under 662 keV γ-ray irradiation, we determined absolute scintillation light yield of 2340 ph/MeV for the 2.0% Tm doped sample. Taking into account whole optical and scintillation properties, 2.0% doping was the best for Tm-doped LPS crystals. • We successfully synthesized LPS single crystals with Tm doping concentration of 0.1 to 5.0 % by the FZ method. • When we irradiated X-rays, we observed the scintillation emission at 360 and 460 nm caused by Tm3+ 4f-4f transitions. • Under 662 keV γ-ray, scintillation light yield of Tm doped LPS reached up to 2340 ph/MeV with the 2.0 % Tm doped sample. • The optimal Tm doping concentration in the LPS single crystal for a scintillator was determined to be around 2.0 %. [ABSTRACT FROM AUTHOR]

We report on successful synthesis and comprehensive study of luminescence spectroscopic properties and decay kinetics of undoped and Ce3+-doped eulytite structure orthophosphate Ba 3 La(PO 4) 3 (BLP) upon excitation with UV-VUV and X-ray photons in a wide temperature range. An intrinsic emission located in the UV range is observed for undoped BLP upon both VUV and X-ray excitation. In turn, emission of Ce3+-doped BLP is represented by interconfigurational 5d-4f transitions arising from Ce3+ ions located in two crystallographic sites which demonstrate average decay time of 22 ns and 40 ns upon intracenter excitation. Pulse X-ray excitation results in appearance of slower (μs or longer) decay components and acceleration of the main 5d-4f emission decay component. Host sensitization of Ce3+ emission is well demonstrated by UV-VUV excitation spectra measurements both at liquid helium and at room temperature. Mechanisms influencing the efficiency and time scale of energy transfer from the host to Ce3+ dopant ions are analyzed and discussed while aiming to estimate the potentials of BLP:Ce3+ for scintillator and X-ray phosphor applications. Image 1 • An intrinsic emission was observed for undoped Ba 3 La(PO 4) 3 at low-temperature. • Efficient energy transfer from the host to Ce3+ ions is realized through excitonic mechanism. • BLP:Ce3+ is found potential for X-ray phosphor and scintillator applications. [ABSTRACT FROM AUTHOR]

A pseudospark (PS)-sourced electron beam of 3-mm diameter has been experimentally investigated. Emission of X-rays was detected during a PS discharge and clear X-ray images were formed using the PS-sourced electron beam impacting on a 0.1-mm-thick molybdenum target at an applied voltage of 46 kV. Using a phosphor-coated scintillator, the beam's cross-sectional profile and surrounding ion channel were also observed. These results confirm the presence of an electron beam. [ABSTRACT FROM PUBLISHER]