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The CsPbX 3 perovskites have demonstrated promising applications in the field of X-ray detection. Appropriate element doping to substitute Pb in CsPbX 3 not only improves the photoresponse performance of the resulting material but also reduces the Pb content for achieving environmental protection. Herein, X-ray detectors based on Sr-doped CsPb 1-x Sr x Br 3 thick films were developed. The effects of Sr doping concentration were investigated. The incorporation of Sr increased the density of the CsPbBr 3 thick film and modulated the bandgap of the materials. CsPb 1-x Sr x Br 3 exhibited good optical responses at different bias voltages and X-ray doses. The X-ray response improved as the Sr-doping concentration increased. Therefore, the partial substitution of Sr into CsPbBr 3 is suitable for reducing the Pb content in X-ray detectors. Furthermore, the development of CsPb 1-x Sr x Br 3 thick films provides a new strategy for the detection of X-rays. [ABSTRACT FROM AUTHOR]

The silicon-on-insulator pixel (SOIPIX) detector is a unique monolithic-structure imaging device currently being developed by the SOIPIX group led by the High Energy Accelerator Research Organization (KEK). The detector team at KEK Photon Factory (PF) is also developing an X-ray camera using INTPIX4NA with a 14.1 × 8.7 mm2 sensitive area and 425,984 (832 column × 512 row matrix) pixels, with a pixel size of 17 × 17 µm2. The detector has high resolution and sensitivity for low-intensity X-rays, making it suitable for imaging in optical systems with lower X-ray intensities, such as an X-ray zooming microscope using two Fresnel zone plates (FZPs), which is also under development at PF. To enable imaging under such conditions, we developed a detector cooling system using a Peltier element to support longer exposure time (0.5 s per frame). Additionally, we developed a new readout system using DAQ boards developed by PF, equipped with SiTCP-XG (network controller implemented on field-programmable gate array) that supports 10 Gbps Ethernet for high-frame-rate imaging at several hundred hertz. The new X-ray camera was tested at the PF BL-14A, BL-14B, and AR-NE1A experimental stations, and the resolution and sensitivity characteristics were confirmed. Given these confirmed characteristics, this X-ray camera is suitable for X-ray imaging using 5–20 keV X-rays under low-intensity, low-contrast conditions. These conditions are ideal for capturing soft tissues with poor contrast, objects with fine structures, and specimens vulnerable to radiation damage. • SOIPIX INTPIX4NA detector based X-ray camera was developed at KEK Photon Factory. • INTPIX4NA detector has a 14.1 × 8.7 mm2 sensitive area (17 μ m pitch 832 × 512 pixel matrix). • This is suit for imaging with 5–20 keV X-ray under low-intensity/contrast conditions. • 10GbE DAQ system and Peltier based detector cooling system were also developed. • The resolution and sensitivity characteristics were tested/confirmed at KEK PF. [ABSTRACT FROM AUTHOR]

XRPIX is the monolithic X-ray SOI (silicon-on-insulator) pixel detector, which has a time resolution better than 10 μ s as well as a high detection efficiency for X-rays above 10 keV. XRPIX is planned to be installed on future X-ray satellites. To mount on satellites, it is essential that the ADC (analog-to-digital converter) be implemented on the detector because such peripheral circuits must be as compact as possible to achieve a large imaging area in the limited space in satellites. Thus, we developed a new XRPIX device with the on-chip ADC, and evaluated its performances. As the results, the integral non-linearity was evaluated to be 6 LSB (least significant bit), equivalent to 36 eV. The differential non-linearity was less than 0.7 LSB, and input noise from the on-chip ADC was 5 e −. Also, we evaluated end-to-end performance including the sensor part as well as the on-chip ADC. As the results, energy resolution at 5.9 keV was 294 ± 4 eV in full-width at half maximum for the best pixel. [ABSTRACT FROM AUTHOR]

With the extensive application of object detection in intelligent security, the demand for detecting prohibited items in X-ray images has become increasingly stringent. Unlike natural images, X-ray images present unique challenges such as complex backgrounds and mutual occlusion between prohibited and normal items. Consequently, applying traditional detection methods to X-ray images remains a significant challenge. To tackle these challenges, we have developed a unique frequency-aware dual-stream transformers (FDTNet) that is specifically designed for analyzing X-ray images. The FDTNet consists of two streams: one handles the original image, while the other deals with an image that has been enhanced with frequency domain features. In order to achieve precise detection of prohibited items, we introduce a frequency-aware module (FAM) that enhances the representation of prohibited items by utilizing information from the frequency domain. This FAM can be easily integrated into other backbones or detectors as it is a plug-and-play module. Additionally, to enhance the fusion of feature maps from both streams, we utilize a global and channel attention module (GCA) that aggregates texture representations for spatial feature streams. Our evaluation of the proposed FDTNet on the OPIXray datasets and PIDray datasets demonstrates that our detection mAP achieves 88.02 and 68.2, respectively. Extensive experiments conducted on publicly available datasets provide substantial evidence that our proposed network significantly improves the detection of prohibited items compared to state-of-the-art methods. [Display omitted] • The dual-stream design is used to extract RGB features and frequency features respectively • Global and channel attention module enhances the features generated by the RGB stream using attention mechanisms. • Frequency-aware module encodes frequency features, enabling better capture frequency information. [ABSTRACT FROM AUTHOR]

CsI(Tl) scintillator has been widely used in X-ray flat-panel detectors due to excellent performance characteristics including a suitable Si-photodiode emission wavelength, excellent optical output, and fast decay time. Here, a solution-based space-confined growth method was presented to achieve CsI(Tl) scintillator single-crystal flakes with controllable thickness. The grown CsI(Tl) single-crystal flake exhibits a comparable light yield (∼72,000 photons/MeV) and a lower afterglow level (0.1% @ 21 ms, 0.01% @ 118 ms) in comparison to that by the traditional melting method. This space-confined method allows for the achievement of a single crystal thickness of only 0.27 mm, making it suitable for direct application in X-ray detection and other related fields. It may open up new possibilities for the development of halide scintillator single crystals. A solution-based space-confined growth method enables the growth of high-quality CsI(Tl) single crystal flakes with controlled thickness for X-ray flat-panel detectors. [Display omitted] • A space-confined solution method is used to grown CsI(Tl) single-crystal flakes. • The thickness of the CsI(Tl) flake grown using this method can be controlled to be as thin as approximately 0.27 mm. • The CsI(Tl) flake exhibits a lower afterglow and a comparable light yield in comparison to that by the melting method. [ABSTRACT FROM AUTHOR]

Perovskite X-ray detectors are actively investigated because of their exceptional properties, including their significant attenuation coefficient, low defect density, excellent transport characteristics, easy growth, and high sensitivity to X-ray photons. However, perovskite-based high-energy X-ray detectors on the MeV scale are rarely explored. In this study, we investigate the optoelectronic characteristics and radiation detection capabilities of triple-cation Cs 0.05 FA 0.9 MA 0.05 PbI 3 single crystals (CSC) grown using the inverse temperature crystallization method. The CSCs with a reduced Goldschmidt tolerance factor owing to the presence of Cs and MA ions exhibit exceptional properties, including a bandgap of 1.447 eV, low dark current, and self-powered response to X-ray irradiation. The X-ray absorption rate of 36 keV exceeded 99% with a CSC thickness of 2 mm, demonstrating its strong stopping power. Moreover, the CSC detectors exhibit precise linear responses to varying X-ray doses and dose rates with R2 values close to 1 and relative standard deviation (RSD) values below 3% under all the tested conditions. In addition, the detector effectively detected high-energy X-rays of up to 15 MV with minimal variations in the RSD values. These findings highlight the potential of CSC as promising materials for high-performance X-ray detectors. • Triple-cation lead–halide perovskites for high-energy X-ray detection were studied. • CSC detector has uniform linear response to varying X-ray doses and rates. • CSC detector can detect high-energy X-rays of up to 15 MeV. • CSC demonstrated remarkable promise as excellent self-powered X-ray detectors. [ABSTRACT FROM AUTHOR]

X-ray detection and imaging have arose lots of attentions in modern society, due to its stronger penetrating ability. This review highlights the potential of different kinds of halide perovskites for direct X-ray detector and imager, and systematically summaries current progress on them, as well as a brief outlook presents for further boosting their performances. [Display omitted] X-ray detection has significantly applied in medical diagnostics, railway flaw detection, security screening, non-destructive testing in industrial products and quality inspection in food industry et al. Recently, as one of the alternative materials, halide perovskites show great potential in high-performance X-ray detector for their relatively high atomic number, superior carrier life-time produce, tunable band gap, and low temperature fabrication process. Accordingly, based on halide perovskite, some advanced and meaningful work was conducted, and corresponding performances of X-ray detector have reached a comparative height. Herein, we aim at systematically summarizing current progress on halide perovskite based X-ray detectors: (1) First, an introduction of background and key parameters is provided to understand the X-ray detectors clearly; (2) After that, we put an emphasis on the advanced work for various halide perovskites based X-ray detectors. Meanwhile, their optimized strategies and applications in imaging are presented; (3) Finally, the challenges remained and promising opportunities are also presented, for further boosting the performance of halide perovskites based X-ray detectors. [ABSTRACT FROM AUTHOR]

[Display omitted] CsPbBr 3 -CsPb 2 Br 5 wafer is obtained by water-assisted coprecipitation method, and a spray-coating method is further utilized to convert it into CsPbBr 3 -CsPb 2 Br 5 -CsPbI x Br 3-x composite wafer, which exhibits superior performance and reliability of X-ray detection. • Water-assisted coprecipitation is proposed to prepare high-quality CsPbBr 3 -CsPb 2 Br 5 powder. • CsPbBr 3 -CsPb 2 Br 5 wafer is obtained by pressure-induced aggregation of the powder. • Spray-coating of CsI/H 2 O onto CsPbBr 3 -CsPb 2 Br 5 wafer can convert it into CsPbBr 3 -CsPb 2 Br 5 -CsPbI x Br 3-x composite wafer. • X-ray detector with the composite wafer exhibits much improved performance and reliability. Lead halide perovskite wafers with large lateral size, controllable thickness, and desirable optoelectronic characteristics are promising for X-ray detectors. Herein, CsPbBr 3 -CsPb 2 Br 5 -CsPbI x Br 3-x composite wafers are prepared via water-assisted coprecipitation and spray coating. The preparation involved pressure-induced aggregation of the CsPbBr 3 -CsPb 2 Br 5 powder produced through coprecipitation using of H 2 O/MeOH mixed solvent into CsPbBr 3 -CsPb 2 Br 5 wafers, followed by spraying a CsI/H 2 O solution onto the wafer surface to transform it into a CsPbBr 3 -CsPb 2 Br 5 -CsPbI x Br 3-x composite wafer. Multiple favorable properties, including compact surface, high crystallinity, excellent carrier transportation, large/adjustable size, low cost, and mass producibility, can be identified for the CsPbBr 3 -CsPb 2 Br 5 -CsPbI x Br 3-x composite wafer. An X-ray detector with high performance and excellent stability is realized with this wafer. It yields high resistivity (ρ; 1.3 × 109 Ω cm−2, exceptional carrier mobility (μ)/lifetime (τ) (μτ) product (1.01 × 10−3 cm2 V−1), high sensitivity (20555.1 μC Gy air −1 cm−2), and low detection limit (127.7 nGy s−1). Hence, our research provides a reliable strategy for optimizing the structure and performance of perovskite wafer-based X-ray detectors and enabling mass preparation. [ABSTRACT FROM AUTHOR]

Gotthard-II (G-II) is a 1-D silicon microstrip hybrid detector developed by the Paul Scherrer Institut within the framework of a collaboration agreement with the European XFEL. The ASIC features a dynamic gain switching architecture, in order to cope with the luminosity of European XFEL, and a 12-bit analog-to-digital converter with a sampling/conversion rate of more than 18 MS/s as well as a Static random-access memory, making it capable of matching the European XFEL pulse train structure, thus acquiring up to 2700 images at 4.5 MHz per burst. The sensor's strip pitch can be either of 50 μ m or 25 μ m , for a total of 1280 or 2560 output channels per detector, respectively, with a spectral sensitivity that allows either X-ray detection (optimized in the 5–20 keV range) or visible light detection. Its exceptionally good compliance with the European XFEL beam conditions will make G-II the most widely employed detector across the facility, with a total of 29 modules of different flavors that will be installed in scientific instruments and beam diagnostic setups. Although the detector will be predominantly used for spectroscopic measurements it will have a variety of other applications, including X-ray diffraction/emission/absorption experiments, relative pulse arrival time monitoring (of fundamental importance for pump–probe experiments), spectral diagnostics, and beam quality monitoring, with the possibility for the detector itself to generate a veto patterns for the large area MHz framerate pixel detectors employed at the scientific instruments, such as AGIPD, LPD and DSSC. In this paper, an overview of G-II detector technology and its usage at the European XFEL will be presented; the focus will then move on towards the process of detector integration in the European XFEL control system, data acquisition, and data correction infrastructure, highlighting its challenges. Finally, an overview of the first results obtained at scientific instruments will be given. [ABSTRACT FROM AUTHOR]

Metal halide perovskites have gained significant attention as promising materials for ionizing radiation detection due to their facile fabrication process, exceptional optoelectronic properties and high attenuation coefficients. To effectively absorb the incident X-ray photons, thick active layers have been reported and fabricated via spray-coating. However, the conventional spray-coating method is susceptible to various adverse effects, making it challenging to achieve high-quality thick perovskite films. In this work, we propose the use of antisolvent-assisted spray-coating to deposit perovskite films, which results in small surface roughness, thick films on various substrates. The slow growth of the thick film and the ability to regulate its crystallization through the modulation of processing atmosphere were also carefully studied. The optimized X-ray detector demonstrated a sensitivity of up to 3370.8 μC Gy air −1 cm−2, demonstrating its great potential for X-ray detection applications. • Anti-solvent spray-coating technique was established to deposit perovskite thick films. • The spray-coating process was systematically investigated and optimized. • Optimized devices based on antisolvent-assisted X-ray detectors are promising for real applications. [ABSTRACT FROM AUTHOR]

X-ray free-electron lasers (XFEL) provide unique opportunities for hard X-ray emission spectroscopy (XES) in solution phase by enabling femtosecond temporal resolution. The high brilliance and MHz repetition rate of such sources drive the development of specialized sample delivery systems to overcome the challenges of sample degradation, as well as major advances of multiple-gain detectors to fully utilize the high dynamic range required for X-ray detection. This paper addresses the experimental limitations that arise in a typical XES experiment performed on fast liquid jets at the MHz repetition rate of the European XFEL. Using a low-noise gain-switching JUNGFRAU detector allows taking advantage of the high dynamic range and high sensitivity, but restricts a single-shot detection due to the limited frame rate. The gain transition regions of the detector response may exhibit nonlinear behavior that can be identified and efficiently corrected using the internal reference-based normalization and linearization approaches described here. [ABSTRACT FROM AUTHOR]

We report on the synthesis and characterization of composite semiconducting polymer – nanoparticle membranes for X-ray detection applications. The membranes are made of poly(vinyl alcohol) (PVA) organic polymer that is doped with ionic liquid (IL) to control its electrical conductivity. Tl 2 O 3 nanoparticles with different weight concentrations are added to the polymer, and membranes are produced using solution casting method. The nanoparticles are synthesized using a microwave assisted technique under controlled temperature and pressure, and their average size is 13.0 ∓ 1.9 nm. Structural and compositional tests confirm the fabrication of homogeneous polymer-nanoparticle films. Electrical impedance tests are conducted as a function of nanoparticle concentration and temperature for the membranes, and they reveal that the dc electrical resistance of the membranes decreases with increasing both nanoparticle concentration and temperature. The activation energy was found to increase with increasing nanoparticle concentration. The membranes are utilized as conductometric X-ray sensors, and their response increases with increasing X-ray generator voltage. The fabricated composite membranes exhibit semiconducting properties, easy to fabricate, low cost, and qualify practical device utilization in the X-ray dosimetry sector. • Composite membranes of polymer-nanoparticles were are synthesized • The membranes comprise of PVA, glycerol, and Tl 2 O 3 nanoparticles. • The nanoparticles were synthesized using a sol-gel modified method • Electrical characterization demonstrated that as nanoparticle concentration increases, the activation energy increase. • The membranes are suitable for potential applications in x-ray dosimetry field. [ABSTRACT FROM AUTHOR]

Abstract High Energy Photon Source (HEPS) with a beam energy of 6 GeV and emittance less than 1.0 nm rad will be constructed in China, which can provide high-brightness hard X-ray in the order of 1022 (phs/s/mm2/mr2/0.1%B.W.). The broadband and high-brightness monochromatic beam flux and white beam flux need new detector other than the ion chambers for measurement in case of saturation under high-flux conditions. The Diamond X-ray detector for the beam position monitoring and high brightness X-ray detection is developing for High Energy Photon Source in China. The diamond detector has advantages over other detector materials: a low atomic number resulting in a low absorption cross-section when used as beam position monitor and a high radiation and wide linear range when used as beam intensity measuring. In this paper, the polycrystalline chemical-vapour-deposition diamond detectors with an aluminium contact have been tested at 1W2B beamline at Beijing Synchrotron Radiation Facility (BSRF). A transmission-mode diamond X-ray detector is designed to simultaneously measure the X-ray flux, beam position in real time. [ABSTRACT FROM AUTHOR]

The influence of line-broadening and zero shift of the sensor on identifying spectral lines was eliminated by an improved K-medoids clustering algorithm after performing principal component analysis on the spectral band of interest. The intensity ratio of the acquired spectral lines was calculated and dealt with by empirical mode decomposition to predict the existence of porosity based on the method given by our previous study. Furthermore, the effect of sheet gap on porosity formation was investigated by the proposed method. The analysis results were verified by X-ray detection, which demonstrated the distribution of porosity as well. The results showed that an appropriate gap could contribute significantly to reducing the porosity. The spectral sensor system and analysis method proposed in this study may help decrease the testing costs and increase productivity, while maintaining high weld quality. [ABSTRACT FROM AUTHOR]

In recent years, scientific CMOS (sCMOS) sensors have been vigorously developed and have outperformed CCDs in several aspects: higher readout frame rate, higher radiation tolerance, and higher working temperature. For silicon image sensors, image lag will occur when the charges of an event are not fully transferred inside pixels. It can degrade the image quality for optical imaging, and deteriorate the energy resolution for X-ray spectroscopy. In this work, the image lag of a sCMOS sensor is studied. To measure the image lag under low-light illumination, we constructed a new method to extract the image lag from X-ray photons. The image lag of a customized X-ray sCMOS sensor GSENSE1516BSI is measured, and its influence on X-ray performance is evaluated. The result shows that the image lag of this sensor exists only in the immediately subsequent frame and is always less than 0.05% for different incident photon energies and under different experimental conditions. The residual charge is smaller than 0. 5 e − with the highest incident photon charge around 8 ke − . Compared to the readout noise level around 3 e − , the image lag of this sensor is too small to have a significant impact on the imaging quality and the energy resolution. The image lag shows a positive correlation with the incident photon energy and a negative correlation with the temperature. However, it has no dependence on the gain setting and the integration time. These relations can be explained qualitatively by the non-ideal potential structure inside the pixels. This method can also be applied to the study of image lag for other kinds of imaging sensors. [ABSTRACT FROM AUTHOR]

X-ray detectors have drawn great attention due to their wide applications in medical imaging and industrial inspection. Lead halide perovskite exhibits excellent X-ray detection merits because of its high-Z element and outstanding photoelectric properties. However, the perovskite-based X-ray detectors exhibit poor stability, low resistivity and large dark leakage current due to the soft lattice and ion migration of perovskite materials. Herein, we used Ga 2 O 3 compact layer to form a heterojunction structure with formamidinum lead iodide (FAPbI 3) to largely ease these issues. Compared with the bare FAPbI 3 detector, the dark current of the FAPbI 3 /Ga 2 O 3 heterojunction detector is reduced by 3 orders of magnitude and the photo-to-dark current ratio (PDCR) increased by 31-fold. The detection limit of 0.23 mGys−1 is obtained which is 20 times lower than the FAPbI 3 detector and short response time of 20 ms is obtained. More importantly, the FAPbI 3 /Ga 2 O 3 device exhibits better repeatability due to the suppression of ion migration by Ga 2 O 3. This work provides an effective strategy to obtain low dark current and stable perovskite-based photodetector. • A coplanar interdigital MSM-structured X-ray detector was fabricated based on FAPbI 3 /Ga 2 O 3 heterojunction. • Low dark current density (4.1 pAmm−2), high PDCR (433) and low detection limit (0.23 mGys−1) were obtained. • The performance improvement of the device is due to the suppression of iodine ions migration by compact Ga 2 O 3. [ABSTRACT FROM AUTHOR]

The study of Soft X-ray emission can be a source of fundamental information, particularly for what concerns tokamaks and plasma diagnostics, but also in general in the fields of high energy and nuclear physics. Detection systems based on Gas Electron Multipliers (GEM) technology can be of particular use in the context of X-ray analyses, being relatively low cost while maintaining good spatial and temporal resolution and capability to sustain high counting rates (up to MHz/mm2). The development of these new and improved detectors is thus of interest, especially in the research about diagnostic and control of machines for fusion energy. In this work, the performance of a new triple-GEM detector, characterized by an aluminum metallic coating on both layers of the GEM foils, is presented and a comparison is made with the more conventional design employing copper coating. The performances of an aluminum-coated GEM (Al-GEM) detector and of a standard copper-coated GEM (Cu-GEM) detector in revealing quasi-monochromatic X-ray beams coming from different fluorescence materials are compared. The Al-GEM detector is shown to less suffer the issue of unwanted background on the signal caused by the presence of copper inside the detector itself. The suppression of this noise source encourages the use of Al-GEM detectors to perform spectroscopy in harsh environments, such as tokamak machines, where soft X-rays are useful probes to control different plasma properties and parameters. [ABSTRACT FROM AUTHOR]

Recently, semiconductive polymeric materials have attracted attention as an active layer for detecting ionizing radiation because of their excellent properties such as flexibility, easy production, solution processability and low-cost production. This paper presents X-ray detection properties of Poly(3-hexylthiophene) (P3HT):Phenyl C61 butyric acid methyl ester (PCBM) blend structure with different PCBM loading ratios. P3HT:PCBM mixing ratio was changed from 1:0 to 1:2. Top contact of the pure and blend structured device were produced by using a solution based graphite ink. Devices were constructed with vertical bulk resistive architecture within an ohmic electrode structure as ITO/PEDOT:PSS/P3HT:PCBM/Graphite configuration. Graphite electrode was coated on the active layer with the spray coating method. All devices exhibited ohmic current-voltage (I–V) characteristics. The blend structured devices exhibited stable saw-tooth type behaviour in photocurrent responses against the on and off states of X-rays. Saw-tooth type responses could be evaluated as major evidence for a potential usage of organic electronic device technology direct radiation detectors. Although the best sensitivity value to X-ray was obtained with the blend structure with equal ratio, it was observed that the rise and decay times were shortened with the increase in the amount of PCBM in the blend structure from. [Display omitted] • P3HT:PCBM active layer based X Ray detectors. • Spray coated graphite electrode was used as the top ohmic contact for all devices. • P3HT:PCBM ratio was changed as (1:0), (1:0.5), (1:1), (1:2). • Best sensitivity value to X-ray was obtained with the blend structure with equal ratio of PCBM and P3HT (1:1). [ABSTRACT FROM AUTHOR]

The aims of this study is to improve the sensitivity of indirect X-ray detectors by investigating the properties and application of ternary-blended organic active layers. The ternary-blended active layers studied were composed of conjugated polymer PBDB-T-2F as the donor (D1), non-fullerene Y6 as the first acceptor (A1) and ITIC-4F as the second acceptor (A2). The structural similarity between the two acceptors allows the advantage formation of a homogeneous acceptor phase and results in good film morphology. Another advantage of our approach is the electrical and optical characteristics of the active layer can be modulated based on the mixing ratio of the two acceptors. To find the optimal ternary blending, the content of D1 was fixed while the A1:A2 content ratio was adjusted. The CsI (Tl) scintillator-coupled detector with an active layer of PBDB-T-2F:Y6:ITIC-4F = 1.0:0.6:0.4 achieved the highest sensitivity of 4.27 × 103 μC∙Gy air −1∙cm−2 giving respective improvements of 27.10% and 43.92% compared to binary-blend PBDB-T-2F:Y6 = 1:1 and PBDB-T-2F:ITIC-4F = 1:1. Next, the active layer's spin-coating conditions and the bias conditions were examined to further improve the sensitivity of the detector. Finally, the detector with a PBDB-T-2F:Y6:ITIC-4F = 1.0:0.6:0.4 active layer was shown to have the highest sensitivity of 5.42 × 103 μC∙Gy air −1 cm−2 at a bias of – 1.6 V with a 97 ± 2 nm thick active layer. The aims of this study are to improve the sensitivity of indirect X-ray detectors by investigating the properties of ternary-blended organic active layers. The structural similarity between the two acceptors allows the advantage formation of a homogeneous acceptor phase and results in good film morphology. Another advantage of our approach is the electrical and optical characteristics of the active layer can be modulated based on the mixing ratio of the two acceptors. The CsI (Tl) scintillator-coupled detector with ternary-blended active layer giving respective improvements of 27.10% and 43.92% compared to binary-blended active layer. [Display omitted] • To improve the sensitivity of the X-ray detector, a ternary-blend strategy was applied to the organic active layer. • The X-ray detector using ternary-blended active layer shown 27.10% and 43.92% higher sensitivity compared to their respective binary combinations (PBDB-T-2F:Y6 and PBDB-T-2F:ITIC-4F). • The indirect-type X-ray detector using PBDB-T-2F:Y6:ITIC-4F = 1.0:0.6:0.4 ternary-blended active layer was achieved a high sensitivity of 5.42 × 103 μC∙Gy air −1∙cm−2. [ABSTRACT FROM AUTHOR]

This paper reports the latest technological development on the Low Gain Avalanche Detector (LGAD) and introduces a new architecture of these detectors called inverse-LGAD (iLGAD). Both approaches are based on the standard Avalanche Photo Diodes (APD) concept, commonly used in optical and X-ray detection applications, including an internal multiplication of the charge generated by radiation. The multiplication is inherent to the basic n ++ –p + –p structure, where the doping profile of the p + layer is optimized to achieve high field and high impact ionization at the junction. The LGAD structures are optimized for applications such as tracking or timing detectors for high energy physics experiments or medical applications where time resolution lower than 30 ps is required. Detailed TCAD device simulations together with the electrical and charge collection measurements are presented through this work. [ABSTRACT FROM AUTHOR]

For the research on alpha emitters used for targeted alpha particle therapy such as astatine-211 (211At), alpha particle as well as X-ray imaging are required for autoradiography and phantom imaging or in vivo imaging of small animals. Consequently, two imaging detectors for different types of radiations are required in such research. However, preparing two types of imaging detectors needs cost and space. If a single imaging detector could image alpha particles as well as X-rays for 211At, it would be an advance in the imaging research for targeted alpha particle therapy. Consequently, we developed a detector that can be used for both alpha particle and X-ray imaging. The developed imaging detector is a phoswich type made of a ZnS(Ag) sheet and a cerium doped YAlO 3 (YAP(Ce)) plate optically coupled to each other with a 1-mm-thick light guide between scintillators. These scintillators were optically coupled to a 1-inch-square position-sensitive photomultiplier tube (PSPMT) to form an imaging detector. The ZnS(Ag) sheet detects alpha particles while the YAP(Ce) plate detects X-rays from 211At. Due to the pulse height difference between alpha particles and X-rays, a different high voltage was supplied to the PSPMT for alpha particle and low-energy X-ray detection. Discrimination between alpha particles and X-rays were conducted by pulse height as well as pulse shapes of ZnS(Ag) and YAP(Ce). The intrinsic spatial resolution for 5.5-MeV alpha particles was better than 0.6 mm the full width at half maximum (FWHM), while that for 60-keV gamma photons was ∼1.2 mm FWHM. Energy resolution for 5.5-MeV alpha particles was 60% FWHM, while that for 60-keV gamma photons was 25% FWHM. With a 4-mm-thick, 0.6-mm-diameter parallel hole collimator mounted on the detector, the system spatial resolution for 60-keV gamma photons was ∼2 mm FWHM within 5 mm from the collimator surface, and its sensitivity was 0.5%. An image of the 211At alpha particle distribution of a sliced kidney as well as an X-ray image of a paper soaked with 211At solution could be obtained. We conclude that the developed detector is promising for single-detector imaging of alpha particles as well as X-rays from 211At. • A phoswich detector composed of ZnS(Ag) and YAP(Ce) for astatine-211 imaging was developed for both alpha particles and X-rays. • An image of the At-211 alpha particle distribution as well as an X-ray image could be obtained. • The developed detector is promising for imaging of alpha particles as well as X-rays from At-211. [ABSTRACT FROM AUTHOR]

Highlights: [•] A diode was designed in the shape of a silicon cube with p–n junctions on all sides. [•] The purpose was to create an X-ray detector with angular independent response. [•] The cubes were manufactured with a micromachining process. [•] The angular variation in the response was reduced with a factor 7. [ABSTRACT FROM AUTHOR]

Abstract: Conventional semiconductor X-ray detectors for medical imaging have either a planar or a pixelated structure. The options available for detection materials are limited by the natural trade-off between the absorption of incident photons and the collection of free charge carriers with these two structures. This trade-off can be avoided by using az 3D structure, in which electrodes are drilled into the detector's volume. This article describes a prototype 3D semiconductor detector, using semi-insulating GaAs. A laser drilling technique was used to create electrodes in the volume of the material. The holes created were characterized by scanning electron microscopy. Electrode contacts were created using electroless Au deposition. The manufacturing process and the first gamma counting results obtained with 241Am and 57Co sources are presented. The system is capable of individual photon-counting without energy discrimination but requires further development to improve efficiency. [Copyright &y& Elsevier]

• The 25 µm-thick ZnO film using sputtering method was characterized for X-ray detection applications. • p+-Si/ZnO X-ray detector based on the 25 µm-thick ZnO film shows a high sensitivity of 128 μC∙Gy−1∙cm−2 at − 20 V. • The on-off response is related to the V O defect, which was verified by the transmittance spectrum and the TSC spectrum. [Display omitted] In the field of direct-conversion flat panel X-ray detector, semiconductor with thickness of tens to hundreds microns is needed. In this paper, we demonstrate that thick ZnO semiconductor deposited by RF magnetron sputtering can be candidate for the X-ray detector. The 25 µm ZnO film was prepared by sputtering method under 200 °C and a p+-Si/ZnO X-ray detector based on the thick ZnO film was investigated to explore its X-ray detection properties. The detector shows nonzero short circuit current and open circuit voltage indicating the heterojunction nature of the ZnO film in contact with the p+-Si substrate. The detector shows linear response to the X-ray dose rate and has a high sensitivity of 128 μC∙Gy−1∙cm−2 at −20 V under 30 kV p X-rays indicating its great potential in the flat panel X-ray detector applications. The on-off response of the detector is related to the V O defect in the ZnO film, which can be verified from the transmission spectrum, the thermal stimulated current spectrum, and the photoluminescence spectrum. [ABSTRACT FROM AUTHOR]

Abstract: The paper describes a comprehensive readout electronics system for X-ray imaging using gas-filled detectors to be used at the European Synchrotron Radiation Facility (ESRF). The front-end electronics (named BLADE3) relies on a multi-strips binary parallel readout architecture. BLADE3 features 256 channels in a small space (120×300mm2 printed circuit board) at low power (12mW per channel for the analog processing). It is based on a 16-channel preamplifier-discriminator ASIC (named ASG217) of the trans-impedance type. The ASG217 measured gain (220kΩ), peaking time (15ns), and RMS noise (1.5mV+0.1mV/pF) well match the simulated results. Front-end boards communicate with the back-end electronics using 2Gb/s optical links. The back-end electronics has been implemented in the CompactPCI format and can be operated through a PCI bridge by any host computer. The experience gained with a prototype detector indicates that the front-end electronics meets our requirements. The back-end electronics, already operational for one-dimensional readout, has to be significantly improved for supporting two-dimensional imaging at high photon flux. [Copyright &y& Elsevier]

Abstract: This work is devoted to a more detail testing of overall imaging performance of our developed digital quantum scanner. We enhanced spatial resolution in direction of detection unit movement from 254 down to 85μm. In particular its spatial resolution, resolution in contrast and imaging ability through evaluation images, revealed with various testing objects are performed. For irradiation an X-ray tube was used. The obtained results are discussed in the scope of published results. [Copyright &y& Elsevier]

Abstract: The performance of a xenon high-pressure gas proportional scintillation counter (GPSC) instrumented with a large area avalanche photodiode (LAAPD) as the VUV-photosensor has been investigated for filling pressures from 1 up to 10bar, for 22- and 60-keV photons. The LAAPD photosensor is placed directly within the xenon envelope, as a substitute for the photomultiplier tube, avoiding the constraints of the use of a quartz scintillation window for GPSC-photosensor coupling, which absorbs a significant amount of scintillation and is a drawback for applications where large detection areas and high filling pressures are needed. The lowest energy resolutions are achieved for pressures around 5bar (4.5% and 3.0% full width at half-maximum (FWHM), for 22- and 60-keV photons, respectively). Increasing the pressure to the 8bar range, competitive energy resolutions of 5.0% and 3.6% are still achieved for 22- and 60-keV photons, respectively. This detector could be a compelling alternative in applications where compactness, large detection area, insensitivity to strong magnetic fields, room temperature operation, large signal-to-noise ratio and good energy resolution are important requirements. [Copyright &y& Elsevier]

Abstract: Some examples of space-borne applications that require improvements in detector technology compared with conventional Si and Ge designs are described. Properties of compound semiconductors are noted, and a range of different detector developments are briefly reviewed. Material fabrication improvements for several compound semiconductors have resulted in near Fano-limited performance. [Copyright &y& Elsevier]

Abstract: In the field of the R&D of a new generation hard X-ray cameras for space applications we focus on the use of pixelated CdTe or CdZnTe semiconductor detectors. They are covered with 64 (0.9×0.9mm2) or 256 (0.5×0.5mm2) pixels, surrounded by a guard ring and operate in the energy ranging from several keV to 1MeV, at temperatures between −20 and +20°C. A critical parameter in the characterisation of these detectors is the leakage current per pixel under polarisation (∼50–500V/mm). In operation mode each pixel will be read-out by an integrated spectroscopy channel of the multi-channel IDeF-X ASIC currently developed in our lab. The design and functionality of the ASIC depends directly on the direction and value of the current. A dedicated and highly insulating electronics circuit is designed to automatically measure the current in each individual pixel, which is in the order of tens of pico-amperes. Leakage current maps of different CdZnTe detectors of 2 and 6mm thick and at various temperatures are presented and discussed. Defect density diagnostics have been performed by calculation of the activation energy of the material. [Copyright &y& Elsevier]

Abstract: Since diagnostic X-rays have been proven to be a cause of cancer, some precautions are essential to reduce the dose delivered to patients. In this paper, an idea to reduce the dose by a new type of X-ray computed tomography (CT) using silicon strip detectors is discussed. Thin tungsten plates placed between edge-on silicon strip detectors are the key element to reduce the background of scattered X-rays and improve the image contrast with low dose. The initial results of a feasibility study are also reported. [Copyright &y& Elsevier]

The new era in X-ray spectroscopy of exotic atoms is based on high-resolution reflection-type crystal spectrometers, state-of-the-art X-ray detectors, and sophisticated set-ups to stop the negatively charged particles provided by modern accelerator facilities. Measurements on the elementary systems formed with hydrogen and helium isotopes yield a precision unprecedented in low-energy strong-interaction physics. Spin–spin and spin–orbit effects were identified in antiprotonic hydrogen and hadronic effects were observed for the first time in antiprotonic deuterium. In kaonic hydrogen strong-interaction effects could finally be identified unambiguously. For the pion–proton and pion–deuteron system the measurements reach an accuracy for the hadronic shift of a few per mill, which demands further theoretical effort to extract the scattering lengths at the same level. To allow a precise determination of the pion–nucleon coupling constant, which constitutes a stringent test of the approach for quantum chromodynamics in the non-perturbative regime, a new series of measurements has been started aiming at an accuracy of 1% for the hadronic width in pionic hydrogen. The mass of the charged pion was re-measured by using light pionic and muonic atoms and the first direct observation of Coulomb explosion was achieved for exotic atoms. Tests of bound-state quantum electrodynamics became possible at an accuracy which in turn can be used now to establish X-ray standards in the few keV range by the pionic atoms themselves. [Copyright &y& Elsevier]

Charge-coupled devices (CCDs) are nowadays preferred X-ray detectors in environments with high-background radiation. The maximum number of X-ray counts per exposure in a CCD-detector is limited by saturation. The simulation of this effect reproduces well the measurements with a 55Fe source. In an accelerator area, where a large amount of charged particles is present, a strong reduction of X-ray recognition efficiency with increasing occupancy (percentage of hit pixels) is observed which depends only weakly on the specific distribution of cluster sizes. [Copyright &y& Elsevier]

Recently, halide hybrid perovskites have emerged as an attractive material for radiation detection due to their high atomic numbers and resistivity, large μ τ product (μ is the carrier mobility; τ is the carrier lifetime). However, the sensitivity and stability of perovskite X-ray detectors were limited by ion migration in the perovskites. In this paper, the guanidinium ionic (Gua +) doped MAPbI 3 single crystals were successfully obtained with the solution-processed method. (Gua) 0.06 (MA) 0.94 PbI 3 single crystal shows an activation energy of 589 meV. The X-ray detector with Au/(Gua) 0.06 (MA) 0.94 PbI 3 /Ga structural exhibited a high X-ray sensitivity of 2903 μ C Gy air − 1 cm−2 and a low limit of detection of 7.2 nGy air s − 1. This work shows that a certain amount of Gua + doping into MAPbI 3 could inhibit the ion migration, and significantly improve the X-ray detection performance. [ABSTRACT FROM AUTHOR]

This study compares the real-time dosimetric performance of a bpw34 photodiode (PD) and cold white light-emitting diodes (LEDs) based on diagnostic X-ray-induced signals. Signals were extracted when both the transducers were under identical exposure settings, including source-to-detector distance (SDD), tube voltage (kVp), and current-time product (mAs). The transducers were in a photovoltaic configuration, and black vinyl tape was applied on transducer active areas as a form of optical shielding. X-ray beam spectra and energies were simulated using Matlab-based Spektr functions. Transducer performance analysis was based on signal linearity to mAs and air kerma, and sensitivity dependence on absorbed dose, energy, and dose rate. Bpw34 PD and cold white LED output signals were 84.8% and 85.5% precise, respectively. PD signals were 94.7% linear to mAs, whereas LED signals were 91.9%. PD and LED signal linearity to dose coefficients were 0.9397 and 0.9128, respectively. Both transducers exhibited similar dose and energy dependence. However, cold white LEDs were 0.73% less dose rate dependent than the bpw34 PD. Cold white LEDs demonstrated potential in detecting diagnostic X-rays because their performance was similar to that of the bpw34 PD. Moreover, the cold white LED array's dosimetric response was independent of the heel effect. Although cold white LED signals were lower than bpw34 PD signals, they were quantifiable and electronically amplifiable. • LED-based diagnostic X-ray detection and dosimetry is innovative. • LEDs generated lower radiation-induced signals than the photodiode. • Both the photodiode and LEDs exhibited similar dose and energy dependence. • LEDs were slightly less dose rate dependent than the photodiode. • Both the photodiode and LED radiation-induced signals were ~ 85% precise. [ABSTRACT FROM AUTHOR]

This study compares detector performance through measurements of Contrast-to-Noise Ratio (CNR) of images obtained by a standard commercial X-ray mammography setup, using a flat panel detector with a 200 μ m thick amorphous Selenium (a-Se) sensor, and a laboratory setup, using a Medipix3RX detector with a 1 mm thick Cadmium Telluride (CdTe) semiconductor sensor. The laboratory setup corresponds to the geometry and X-ray spectrum of the commercial setup. Dose calibrations are applied to ensure comparability of results between both systems. Detection of microcalcifications in breast tissue is crucial for early medical diagnosis of breast cancer development, and improvements in image quality or reduction in radiation dose significantly benefit the field of mammography imaging. The Medipix3RX CdTe detector has the potential to improve mammography imaging due to a combination of two features: a photon-counting detection scheme that allows for electronic noise rejection, integrated in a small pixel pitch of 55 μ m; and the higher X-ray photon absorption efficiency of CdTe, compared to materials such as Silicon (Si) or Se, in the mammography energy range. The comparison between both systems shows better CdTe detector performance when imaging microcalcification structures with sizes between 240 μ m and 540 μ m. The Medipix3RX CdTe detector produces higher CNR values as compared to the a-Se system for the studied speck sizes, at equivalent doses, with up to 30% for 540 μ m structures. For 240 μ m size specks, the Medipix3RX CdTe detector has more than twice better CNR performance than a-Se, even for half the dose values. Our results motivate further research to exploit the potential of the Medipix3RX CdTe detector for clinical mammography implementations, due to the benefit of simultaneous radiation dose reduction and improved imaging performance. • Photon-counting X-ray detection results in high contrast to noise ratio mammography. • High detection efficiency materials like CdTe improve contrast with dose reduction. • Image contrast can be improved by detector performance analysis over time. • CdTe detector stability improvements can result in imaging performance improvements. • Smaller pixel size contributes to increased spatial resolution and CNR performance. [ABSTRACT FROM AUTHOR]

• A realistic response function is modeled for the CdTe detectors used in a hard X-ray diagnostic of the TCV tokamak. • The characteristics of the detector observed in the measurement of multiple radioactive. sources are considered in the modeling. • The measured energy spectra of radioactive sources can be correctly reconstructed using the new response function. • The response function is applied to a hard X-ray synthetic diagnostic for the study of energetic electrons. The response function of CdTe detectors used in a hard X-ray spectrometer system (HXRS) on the TCV tokamak fusion experiment is modeled based on the measured energy spectra from multiple gamma-ray sources. The response function consists of an asymmetric Gaussian photopeak, an exponentially inclined shelf structure below the photopeak, and CdTe escape peaks. It is demonstrated that the measured energy spectra of radioactive sources can be correctly reconstructed using this response function. This model is applied to a hard X-ray synthetic diagnostic used to convert a modeled electron distribution function to a measured hard X-ray signal, for the study of energetic electrons in the TCV tokamak. [ABSTRACT FROM AUTHOR]

Abstract: The gaseous micromegas detector designed for the CERN Axion search experiment CAST, operated smoothly during Phase-I, which included the 2003 and 2004 running periods. It exhibited linear response in the energy range of interest (1–10keV), good spatial sensitivity and energy resolution (15–19% FWHM at 5.9keV) as well as remarkable stability. The detector''s upgrade for the 2004 run, supported by the development of advanced offline analysis tools, improved the background rejection capability, leading to an average rate 5×10−5 counts/s/cm2/keV with 94% cut efficiency. Also, the origin of the detected background was studied with a Monte-Carlo simulation, using the GEANT4 package. [Copyright &y& Elsevier]

• Novel crushed perovskite crystal/polymer composite films were prepared by mechanical grinding and sieving processes. • X-ray detectors based on the perovskite/polymer composite films demonstrated excellent stability, low dark current and noise and fast response. • The as-prepared devices exhibited high X-ray sensitivity of ∼488 μC/(Gy air cm2) with lowest detectable X-ray dose rate of 2.3 μGy air /s. Organic-inorganic hybrid perovskite materials have attracted increasing attention in recent years for ionizing radiation detection due to their large cross-section for high energy X-ray or gamma ray, defect-tolerance, large mobility lifetime product, tunable bandgap and facile preparation of single crystals. However, the thickness of solution processed perovskite polycrystalline films are normally limited, and single crystals are fragile and hard to be utilized as a device. In this article, we successfully realized the preparation of the perovskite crystal/polymer composites, through a novel process involving mechanically grinding and sieving. X-ray detectors were fabricated based on the relatively thick composite films via solution process. The device performance under the irradiation of X-rays were also investigated, in terms of stability, dark current, noise and temporal response. Our devices exhibited remarkable performance metrics, which proved that the perovskite composite films can be used to fabricate highly efficient and low-cost X-ray detectors. [ABSTRACT FROM AUTHOR]

Semiconductor sensors are extensively used for X-ray detection, both for spectroscopy and 2D imaging. In this work, the Monte Carlo code PENELOPE v. 2014 with the PenEasy v. 2015 extension was applied for simulating a Medipix3RX detector, including the sensor and the ASIC layers. The code was modified to include the charge dispersion effect modelling at the Pixelated Imaging Detector tally, and validated by investigating the influence of the electric field, incident energy, beam position, pixel size and also by determining the Modulation Transfer Function. The results were compared to experimental data and presented a very good agreement. The Monte Carlo simulation can be used to investigate the detector response and its influence on measured data, such as spatial resolution and X-ray spectra distortion. Besides, the simulation can be applied to determine the energy deposition in each layer of the detector, useful for detection efficiency characterization or radiation damage studies. • Monte Carlo model of a pixel detector. • PENELOPE. • Charge sharing. • Experimental validation. [ABSTRACT FROM AUTHOR]