Formamidinium lead iodide(FAPbI_(3))perovskite exhibits an impressive X-ray absorption coefficient and a large carrier mobility-lifetime product(μτ),making it as a highly promising candidate for X-ray detection appl...Formamidinium lead iodide(FAPbI_(3))perovskite exhibits an impressive X-ray absorption coefficient and a large carrier mobility-lifetime product(μτ),making it as a highly promising candidate for X-ray detection application.However,the presence of larger FA^(+)cation induces to an expansion of the Pb-I octahedral framework,which unfortunately affects both the stability and charge carrier mobility of the corresponding devices.To address this challenge,we develop a novel low-dimensional(HtrzT)PbI_(3) perovskite featuring a conjugated organic cation(1H-1,2,4-Triazole-3-thiol,HtrzT^(+))which matches well with theα-FAPbI_(3) lattices in two-dimensional plane.Benefiting from the matched lattice between(HtrzT)PbI_(3) andα-FAPbI_(3),the anchored lattice enhances the Pb-I bond strength and effectively mitigates the inherent tensile strain of theα-FAPbI_(3) crystal lattice.The X-ray detector based on(HtrzT)PbI_(3)(1.0)/FAPbI_(3) device achieves a remarkable sensitivity up to 1.83×10^(5)μC Gy_(air)^(−1) cm^(−2),along with a low detection limit of 27.6 nGy_(air) s^(−1),attributed to the release of residual stress,and the enhancement in carrier mobility-lifetime product.Furthermore,the detector exhibits outstanding stability under X-ray irradiation with tolerating doses equivalent to nearly 1.17×10^(6) chest imaging doses.展开更多
X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorpho...X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorphous selenium,cadmium telluride zinc,and perovskites,have been utilized in direct conversion X-ray detectors.However,these semiconductor materials are susceptible to temperature-induced performance degradation,crystallization,delamination,uneven lattice growth,radiation damage,and high dark current.This study explores a new approach by coupling an FC40 electronic fluorinated liquid with a specialized high-resolution and high-readout-speed complementary metal-oxide-semiconductor(CMOS)pixel array,specifically the Topmetal II−chip,to fabricate a direct conversion X-ray detector.The fluorinated liquid FC40(molecular formula:C_(21)F_(48)N_(2))is an electronic medium that is minimally affected by temperature and displays no issues with uniform conductivity.It exhibits a low dark current and minimal radiation damage and enables customizable thickness in X-ray absorption.This addresses the limitations inherent in conventional semiconductor-based detectors.In this study,simple X-ray detector imaging tests were conducted,demonstrating the excellent coupling capability between FC40 electronic fluorinated liquid and CMOS chips by the X-ray detector.A spatial resolution of 4.0 lp/mm was measured using a striped line par card,and a relatively clear image of a cockroach was displayed in the digital radiography imaging results.Preliminary test results indicated the feasibility of fabricating an X-ray detector by combining FC40 electronic fluorinated liquid and CMOS chips.Owing to the absence of issues related to chip-material coupling,a high spatial resolution could be achieved by reducing the chip pixel size.This method presents a new avenue for studies on novel liquid-based direct conversion X-ray detectors.展开更多
Although three-dimensional metal halide perovskites are promising candidates for direct X-ray detection,the ion migration of perovskites seriously affects the detector stability.Herein,face-/edge-shared 3D heterometal...Although three-dimensional metal halide perovskites are promising candidates for direct X-ray detection,the ion migration of perovskites seriously affects the detector stability.Herein,face-/edge-shared 3D heterometallic glycinate hybrid perovskitoid Pb_(2)CuGly_(2)X_(4)(Gly=-O_(2)C-CH_(2)-NH_(2);X=Cl,Br)single crystals(SCs),in which the adjacent lead halide layers are linked by large-sized Cu(Gly)_(2)pillars,are synthesized in water.The Cu(Gly)_(2)pillars in combination with face-/edge-shared inorganic skeleton are found able to synergistically suppress the ion migration,delivering a high ion migration activation energy(Ea)of 1.06 eV.The Pb_(2)CuGly_(2)Cl_(4)SC X-ray detector displays extremely low dark current drift of 1.20×10^(-9)nA mm^(-1)s^(-1)V^(-1)under high electric field(120 V mm^(-1))and continuous X-ray irradiation(2.86 Gy),and a high sensitivity of 9,250μC Gy^(-1)cm^(-2)is also achieved.More excitingly,the Pb_(2)CuGly_(2)Cl_(4)nanocrystal can be easily dispersed in water and directly blade-coated on thin-film transistor(TFT)array substrate,and the obtained Pb_(2)CuGly_(2)Cl_(4)-based TFT array detector offers an X-ray imaging capability with spatial resolution of 2.2 lp mm^(-1).展开更多
The solar X-ray detector(SXD)onboard the Macao Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle.The SXD includes two parts:a soft X-ray detection ...The solar X-ray detector(SXD)onboard the Macao Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle.The SXD includes two parts:a soft X-ray detection unit and a hard X-ray detection unit.Both the soft X-ray detection unit and the hard X-ray detection unit include two collimators,two X-ray detectors(a silicon drift detector and a cadmium-zinc-telluride detector),and a processing circuit.Compared with similar instruments,the energy range of the SXD is wider(1–600 ke V)and the energy resolution is better(150 e V at 5.9 ke V,12%at 59.5 ke V,and 3%at 662 keV).展开更多
Metal-halide perovskites are revolutionizing the world of X-ray detectors,due to the development of sensitive,fast,and cost-effective devices.Self-powered operation,ensuring portability and low power consumption,has a...Metal-halide perovskites are revolutionizing the world of X-ray detectors,due to the development of sensitive,fast,and cost-effective devices.Self-powered operation,ensuring portability and low power consumption,has also been recently demonstrated in both bulk materials and thin films.However,the signal stability and repeatability under continuous X-ray exposure has only been tested up to a few hours,often reporting degradation of the detection performance.Here it is shown that self-powered direct X-ray detectors,fabricated starting from a FAPbBr_(3)submicrometer-thick film deposition onto a mesoporous TiO_(2)scaffold,can withstand a 26-day uninterrupted X-ray exposure with negligible signal loss,demonstrating ultra-high operational stability and excellent repeatability.No structural modification is observed after irradiation with a total ionizing dose of almost 200 Gy,revealing an unexpectedly high radiation hardness for a metal-halide perovskite thin film.In addition,trap-assisted photoconductive gain enabled the device to achieve a record bulk sensitivity of 7.28 C Gy^(−1)cm^(−3)at 0 V,an unprecedented value in the field of thin-film-based photoconductors and photodiodes for“hard”X-rays.Finally,prototypal validation under the X-ray beam produced by a medical linear accelerator for cancer treatment is also introduced.展开更多
In comparison to inorganic counterparts,organic semiconducting(OSC)crystalline films are promising for building large-area and flexible ionizing radiation detectors for X-ray imaging or dosimetry due to their tissue e...In comparison to inorganic counterparts,organic semiconducting(OSC)crystalline films are promising for building large-area and flexible ionizing radiation detectors for X-ray imaging or dosimetry due to their tissue equivalence,simple processing and large-scale production accessibility.Fabrication processes,how-ever,hinder the ability to generate aligned and large-area films with high carrier mobility.In this work,the space-confined melt process is used to produce highly orientated 4HCB(4-hydroxycyanobenzene)OSC films with a large area of 15×18 mm^(2).The out-of-plane direction of the 4HCB film is<001>,and the benzene rings are found to be extensively overlapped inside the in-plane direction,according to the XRD patterns.The film exhibits a high resistivity up to 1012cm,and high hole mobility of 10.62 cm^(2)V^(−1)s^(−1).Furthermore,the 4HCB(80μm-thick film)based X-ray detectors can achieve a sensitivity of 93μC Gy air^(−1) cm^(−2)and on/offratio of 157.The device also shows steady flexibility,with no degradation in detecting function after 100 cycles of bending.Finally,the proposed 4HCB film detectors demonstrated a high-resolution X-ray imaging capability.The imaging of several materials with sharp edges(copper and polytetrafluoroethylene)has been obtained.This work has developed a fast but efficient approach for producing large-area,highly oriented OSC films for high-performance X-ray detectors.展开更多
X-ray imaging technologies such as digital radiography(DR),is an important aspect of modern non-destructive testing and medical diagnosis.Innovative flexible X-ray detector technologies have recently been proposed and...X-ray imaging technologies such as digital radiography(DR),is an important aspect of modern non-destructive testing and medical diagnosis.Innovative flexible X-ray detector technologies have recently been proposed and are now receiving increasing attention owing to their superior material flexibility compared with traditional flat-panel detectors.This work aims to study these innovative flexible X-ray detectors in terms of their effectiveness in DR imaging,such as detection efficiency and spatial resolution.To achieve this goal,first,a Monte Carlo model was developed and calibrated to an in-lab 150 kV DR imaging system containing a flat-panel X-ray detector.Second,the validated model was updated with various types of flexible X-ray detectors to assess their performance in nearly realistic conditions.Key parameters such as the detection efficiency pertaining to the crystal material and thickness were studied and analyzed across a broader energy range up to 662 keV.Finally,the imaging performance of the different detectors was evaluated and compared to that of the flat-panel detector in the 150 kV DR imaging system.The results show that the flexible detectors such as the CsPbBr3crystal detector deliver promising performance in X-ray imaging and can be applied to a wider range of application scenarios,especially those requiring accurate detection at challenging angles.展开更多
A flowing gas proportional counter(FGPC)as the detector for astronomical observationin soft X-ray(0.2-3.5keV)range is calibrated on the 3WIB beamline at Beijing Synchrotron Ra-diation Facility(BSRF).The dead time,coun...A flowing gas proportional counter(FGPC)as the detector for astronomical observationin soft X-ray(0.2-3.5keV)range is calibrated on the 3WIB beamline at Beijing Synchrotron Ra-diation Facility(BSRF).The dead time,counting rate plateau curves,X-ray energy linearity,en-ergy resolution and window transparency of the FGPC have been measured.By means of a calibratedphotodiode(AXUV 100G IRD USA,calihrated in NIST)as a standard detector,the efficiency ofthe FGPC as function of photons energy has been obtained with an uncertainty between10%-18%.展开更多
Just as lead-based perovskites that are hot in solar cell preparation, Bi-based perovskites have demonstrated excellent performance in direct X-ray detection, especially the Cs<sub>3</sub>Bi<sub>2<...Just as lead-based perovskites that are hot in solar cell preparation, Bi-based perovskites have demonstrated excellent performance in direct X-ray detection, especially the Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> single crystals (SCs). However, compared with lead-halide perovskites, one challenge for the Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> SCs for X-ray detection application is that it is difficult to prepare large-sized and high-quality SCs. Therefore, how to get a large area with a high-quality wafer is also as important as Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> growth method research. Here, different anti-solvents are used for the preparation of poly-crystalline powder with the Antisolvents precipitation (A) method, as a control, High-energy ball milling (B) was also used to prepare poly-crystalline powders. The resultant two types of Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> wafer exhibit a micro-strain of 1.21 × 10<sup>-3</sup>, a resistivity of 5.13 × 10<sup>8</sup> Ω cm and a microstrain of 1.21 × 10<sup>-3</sup>, a resistivity of 2.21 × 10<sup>9</sup> Ω cm. As a result, an X-ray detector based on the high-quality Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> wafer exhibits excellent dose rate linearity, a sensitivity of 588 μC·Gyairs<sup>-1</sup>·cm<sup>-2</sup> and a limit of detection (LoD) of 76 nGyair·s<sup>-1</sup>.展开更多
Soft X-ray detectors play a vital role in materials science,high-energy physics and medical imaging.Cs_(2)AgBiBr_(6),a lead-free double perovskite,has gained attention for its excellent optoelectronic properties,stabi...Soft X-ray detectors play a vital role in materials science,high-energy physics and medical imaging.Cs_(2)AgBiBr_(6),a lead-free double perovskite,has gained attention for its excellent optoelectronic properties,stability,and nontoxicity.However,its fast crystallization and requirement for high-temperature annealing(>250℃)often lead to inferior film quality,limiting its application in flexible devices.This study introduces an alloying strategy that significantly improves the quality of Cs_(2)AgBiBr_(6)thin films annealed at a reduced temperature of 150℃.Devices based on the alloyed thin films exhibit an ultra-low dark current of 0.32 nA·cm^(-2)and a quantum efficiency of 725%.Furthermore,the first successful integration of Cs_(2)AgBiBr_(6)with a thinfilm transistor backplane demonstrates its superior imaging performance,indicating that Cs_(2)AgBiBr_(6)is a promising material for next-generation soft X-ray sensors.展开更多
The Solar X-ray Detector(SXD)on-board the Macao Science Satellite-1B(MSS-1B)was successfully launched via the Chinese Long March-2C rocket on 21 May 2023,and commenced operations in early June of the same year.The MSS...The Solar X-ray Detector(SXD)on-board the Macao Science Satellite-1B(MSS-1B)was successfully launched via the Chinese Long March-2C rocket on 21 May 2023,and commenced operations in early June of the same year.The MSS-1B/Soft X-ray Detection Units(SXDUs)employ two silicon drift detectors(SDDs),providing a wide range of energy spectra spanning from 0.7 to 24 keV.Notably,the SXDUs deliver a high-resolution capability of 0.14 keV@5.9 keV and operate with a time cadence of 1 second.Here,we perform thorough calibrations of the MSS-1B/SXDUs,employing a combination of ground experiments and simulations.In addition,quantitative analysis comparing the flux measurements obtained by the MSS-1B/SXDUs to the data collected by the Geostationary Operational Environmental Satellite(GOES),provides compelling evidence of their consistency.Furthermore,the preliminary spectral analysis results showcase the robustness and expected performance of the MSS-1B/SXDUs,unlocking their potential for facilitating the study of dynamic evolution of solar flares.Moreover,the innovative MSS-1B/Solar X-ray Detector facilitates concurrent observations of solar soft and hard X-rays,thereby making valuable contributions to the advancements in solar research.展开更多
Lead-halide perovskites have made great advances in direct X-ray detection due to their large mobility-lifetime(μτ),strong X-ray absorption,and ease of synthesis,but the presence of toxic lead and high ionic migrati...Lead-halide perovskites have made great advances in direct X-ray detection due to their large mobility-lifetime(μτ),strong X-ray absorption,and ease of synthesis,but the presence of toxic lead and high ionic migration severely limit their commercial applicability and operational stability.In this study,we substituted toxic Pb^(2+)with Bi^(3+)and Mn^(2+)for preparing eco-friendly two-dimensional lead-free perovskite Cs_(4)MnBi_(2)Cl_(12)single crystal(SC)by a hydrothermal method.The SC possesses smooth surface,good crystallinity,highμτ(1.8×10^(-3)cm^(2)·V^(-1)),and excellent stability.Therefore,the X-ray detector prepared with the Cs_(4)MnBi_(2)Cl_(12)SC achieved an extraordinary sensitivity of 2.1×10^(3)μC·Gyair^(-1)·cm^(-2)and a low limit-of-detection of 1.05 nGyair·s-1.Notably,the detector demonstrates remarkable operational stability,maintaining its original X-ray response even after 6 months of unsealed storage in air,and can function effectively at elevated temperatures up to 100℃,making it highly suitable for application in harsh environments.Moreover,the SC detector achieves high-resolution X-ray imaging because of its outstanding X-ray detection performance.This study not only verifies the feasibility of Cs_(4)MnBi_(2)Cl_(12)SC for high-performance X-ray detection and imaging but also provides new design for preparation of eco-friendly X-ray detectors with both high sensitivity and stability.展开更多
Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.Howev...Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.However,the toxicity of lead in those perovskite heterojunctions limitstheir practical applications.Herein,we report the constructionof the first all-inorganic lead-free Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunctions with an area of 20×20 mm^(2)via a facile liquidphase epitaxial method through temperature-lowering crystallization.The epitaxial crystallization of the three-dimensional(3D)Cs_(2)AgBiBr_(6)SC film on a 2D Cs_(3)Bi_(2)Br_(9)SCsubstrate requires a large driving force for transitioning fromthe Volmer–Weber mode to the layer-by-layer growth modeunder a rapid cooling rate.The Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunction detector achieves a high sensitivity of1390μC Gy_(air)^(−1)cm^(−2)for 100 keV hard X-ray detection atroom temperature,which is enhanced to 2075μC Gy_(air)^(−1)cm^(−2)at 75℃,demonstrating impressive high-temperature stability.Moreover,the detector achieves a detection limit of37.48 nG_(yair)s^(−1)and excellent stability for 90 days without anyencapsulation.This work demonstrates the feasibility of usingthe epitaxial mechanism of perovskite formation on a highsurface-energy substrate for the controllable construction of a3D/2D heterojunction that significantly enhances X-ray detection performance.展开更多
Substance discrimination beyond the shape feature is urgently desired for x-ray imaging for enhancing target identification.With two x-ray sources or stacked two detectors,the two-energy-channel x-ray detection can di...Substance discrimination beyond the shape feature is urgently desired for x-ray imaging for enhancing target identification.With two x-ray sources or stacked two detectors,the two-energy-channel x-ray detection can discriminate substance density by normalizing the target thickness.Nevertheless,the artifacts,high radiation dose and difficulty in image alignment due to two sources or two detectors impede their widespread application.In this work,we report a single direct x-ray detector with MAPbI_(3)/MAPbBr_(3)heterojunction for switchable soft x-ray(<20 keV)and hard x-ray(>20 keV)detection under one x-ray source.Systematic characterizations confirm soft and hard x-ray deposit their energy in MAPbI_(3)and MAPbBr_(3)layer,respectively,while working voltages can control the collection of generated charge carriers in each layer for selective soft/hard x-ray detection.The switching rate between soft and hard x-ray detection mode reaches 100 Hz.Moreover,the detector possesses a moderate performance with~50 nGy s^(-1)in limit-of-detection,~8000μC Gy^(-1)cm^(-2)in sensitivity and ~7 lp/mm in imaging resolution.By defining the attenuation coefficient ratio(μL/μH)as substance label,we effectively mitigate the influence of target thickness and successfully discriminate substances in the acquired x-ray images.展开更多
In recent years,two-dimensional metal halide perovskites(MHPs)have attracted increased attention for radiation detection and imaging.Their detection efficiencies are almost comparable to three-dimensional(3D)perovskit...In recent years,two-dimensional metal halide perovskites(MHPs)have attracted increased attention for radiation detection and imaging.Their detection efficiencies are almost comparable to three-dimensional(3D)perovskites.Meanwhile,they demonstrate superior stability to 3D perovskites.The pursuit of high-quality,phase-pure and lead-free two-dimensional MHP materials and large-area fabrication capability for x-ray detectors are among the research hotspots.In this review,we first give a brief introduction of the crystallographic structure,optoelectronic characteristics and preparation methods of high-quality two-dimensional perovskites.In addition,we overview the general working principles of direct and indirect x-ray detection processes and the corresponding performance metrics from the perspective of detection and imaging.Furthermore,we provide a comprehensive discussion on the recent advances in 2D perovskite x-ray detectors and imaging devices.Finally,we pinpoint several major obstacles of 2D x-ray detectors that should be overcome in the near future.展开更多
On May 21,2023,the Macao Science Satellite-1B(MSS-1B),a low-inclination,low-latitude,and high-precision scientific exploration satellite for geomagnetic fields and space environments,was successfully launched.The sola...On May 21,2023,the Macao Science Satellite-1B(MSS-1B),a low-inclination,low-latitude,and high-precision scientific exploration satellite for geomagnetic fields and space environments,was successfully launched.The solar X-ray detector(SXD),one of the two major scientific payloads onboard the MSS-1B,has obtained a large amount of solar X-ray radiation data,which reveals the distribution law of the magnetic field in the low Earth orbit,as well as the coupling law of the Earth's magnetic field and the solar radiation and energy particle distributions.First,the overall design of the multi-detection-unit,broad-energy-range,small-volume,and low-power SXD was implemented to achieve the scientific objectives of the mission.Second,the technical indicators of the instrument were decomposed into various components,and the key technologies,such as collimator,processing circuit,thermal,and payload dataset designs,were reviewed.Third,the backgrounds,including electronic noise,cosmic diffuse X-ray background,and high-energy background in the Earth's radiation belts in and out of the field of view,were analyzed for the instrument.Then,the ground calibrations of the energy response,detection efficiency,and temperature-dependent peak drift of the SXD flight model were conducted.Finally,the in-orbit temperature,energy spectrum data,background,and solar flare process observation of the instrument in the in-orbit test stage are presented,verifying the instrument design,analysis,and ground calibration,providing a foundation for obtaining accurate solar X-ray radiation data,and achieving the scientific objectives of the satellite.展开更多
A diamond film with a size of 6×6×0.5 mm^3 is fabricated by electron-assisted chemical vapor deposition. Raman spectrum analysis, x-ray diffraction and scanning electron microscope images confirm the high pu...A diamond film with a size of 6×6×0.5 mm^3 is fabricated by electron-assisted chemical vapor deposition. Raman spectrum analysis, x-ray diffraction and scanning electron microscope images confirm the high purity and large grain size, which is larger than 300 μm. Its resistivity is higher than 10^12 W· cm. Interlaced-finger electrodes are imprinted onto the diamond film to develop an x-ray detector. Ohmic contact is confirmed by checking the linearity of its current–voltage curve. The dark current is lower than 0.1 n A under an electric field of 30 k V cm^-1. The time response is 220 ps. The sensitivity is about 125 m A W^-1 under a biasing voltage of 100 V.A good linear radiation dose rate is also confirmed. This diamond detector is used to measure x-ray on a Z-pinch, which has a double-layer 'nested tungsten wire array'. The pronounced peaks in the measured waveform clearly characterize the x-ray bursts, which proves the performance of this diamond detector.展开更多
A prototype of a two-dimensional position sensitive X-ray detector was designed and constructed for small angle X-ray scattering experiments at BSFR （Beijing Synchrotron Radiation Facility）. The detector is based on...A prototype of a two-dimensional position sensitive X-ray detector was designed and constructed for small angle X-ray scattering experiments at BSFR （Beijing Synchrotron Radiation Facility）. The detector is based on MWPC with cathode strip readout, and has a sensitive area of 200 mm×200 mm. The spatial resolution （FWHM） of about 210 μm along the anode wire direction was obtained from the ^55Fe X-ray test of the detector.展开更多
Diamond is a highly suitable material for X-ray detectors that can function effectively in harsh environments due to its unique properties such as ultrawide bandgap,high radiation resistance,excellent carrier mobility...Diamond is a highly suitable material for X-ray detectors that can function effectively in harsh environments due to its unique properties such as ultrawide bandgap,high radiation resistance,excellent carrier mobility as well as remarkable chemical and thermal stability.However,the sensitivity of diamond X-ray detectors needs further improvement due to the relatively low X-ray absorption efficiency of diamond,and the exploration of singlecrystal diamond array imaging still remains unexplored.In the current work,a 10310 X-ray photodetector array was constructed from single-crystal diamond.To improve the sensitivity of the diamond X-ray detector,an asymmetric sandwich electrode structure was utilized.Additionally,trenches were created through laser cutting to prevent crosstalk between adjacent pixels.The diamond X-ray detector array exhibits exceptional performance,including a low detection limit of 4.9 nGy s^(-1),a sensitivity of 14.3 mC Gy^(-1) cm^(-2),and a light-dark current ratio of 18,312,which are among the most favorable values ever reported for diamond X-ray detectors.Furthermore,these diamond X-ray detectors can operate at high temperatures up to 450℃,making them suitable for development in harsh environments.展开更多
All-inorganic CsPbBr_(3)single crystals have emerged as promising candidates for high-energy radiation detectors owing to their exceptional X-ray absorption capabilities,charge transport properties,and high stability....All-inorganic CsPbBr_(3)single crystals have emerged as promising candidates for high-energy radiation detectors owing to their exceptional X-ray absorption capabilities,charge transport properties,and high stability.This study uses first-principles calculations to analyze the structure,band structure,and density of states of different CsPbBr_(3)phases,demonstrating that the orthorhombic phase of CsPbBr_(3)single crystals is more suitable for X-ray detector fabrication.A low-temperature solvent evaporation-induced crystallization method was used to fabricate single crystals to prevent defect introduction during phase transitions.After the introduction of NH_(4)SCN additives,the crystalline quality of the CsPbBr_(3)–NH_(4)SCN single crystals was significantly enhanced,with theμτvalue and bulk resistivity increasing to 1.3×10^(−2)cm^(2)·V^(−1)and 6.8×10^(10)Ω·cm,respectively.The ultimately fabricated CsPbBr_(3)–NH_(4)SCN single-crystal X-ray detector achieved a sensitivity level of 2,360.1μC·Gy_(air)^(−1)·cm^(−2) and a detection limit as low as 424.1 nGy_(air)·s^(−1) under an electric field of 20 V·mm−1.Overall,the experimental results provide new insights into the future fabrication of CsPbBr_(3)single-crystal X-ray detectors.展开更多
基金supports from the National Natural Science Foundation of China(22375220,U2001214,22471302)the Guangdong Basic and Applied Basic Research Foundation(2024B1515020101)Open Project Fund from State Key Laboratory of Optoelectronic Materials and Technologies(OEMT-2024-KF-08).
文摘Formamidinium lead iodide(FAPbI_(3))perovskite exhibits an impressive X-ray absorption coefficient and a large carrier mobility-lifetime product(μτ),making it as a highly promising candidate for X-ray detection application.However,the presence of larger FA^(+)cation induces to an expansion of the Pb-I octahedral framework,which unfortunately affects both the stability and charge carrier mobility of the corresponding devices.To address this challenge,we develop a novel low-dimensional(HtrzT)PbI_(3) perovskite featuring a conjugated organic cation(1H-1,2,4-Triazole-3-thiol,HtrzT^(+))which matches well with theα-FAPbI_(3) lattices in two-dimensional plane.Benefiting from the matched lattice between(HtrzT)PbI_(3) andα-FAPbI_(3),the anchored lattice enhances the Pb-I bond strength and effectively mitigates the inherent tensile strain of theα-FAPbI_(3) crystal lattice.The X-ray detector based on(HtrzT)PbI_(3)(1.0)/FAPbI_(3) device achieves a remarkable sensitivity up to 1.83×10^(5)μC Gy_(air)^(−1) cm^(−2),along with a low detection limit of 27.6 nGy_(air) s^(−1),attributed to the release of residual stress,and the enhancement in carrier mobility-lifetime product.Furthermore,the detector exhibits outstanding stability under X-ray irradiation with tolerating doses equivalent to nearly 1.17×10^(6) chest imaging doses.
基金supported by the National Natural Science Foundation of China(No.12235006)the National Key Research and Development Program of China(No.2020YFE0202002.
文摘X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorphous selenium,cadmium telluride zinc,and perovskites,have been utilized in direct conversion X-ray detectors.However,these semiconductor materials are susceptible to temperature-induced performance degradation,crystallization,delamination,uneven lattice growth,radiation damage,and high dark current.This study explores a new approach by coupling an FC40 electronic fluorinated liquid with a specialized high-resolution and high-readout-speed complementary metal-oxide-semiconductor(CMOS)pixel array,specifically the Topmetal II−chip,to fabricate a direct conversion X-ray detector.The fluorinated liquid FC40(molecular formula:C_(21)F_(48)N_(2))is an electronic medium that is minimally affected by temperature and displays no issues with uniform conductivity.It exhibits a low dark current and minimal radiation damage and enables customizable thickness in X-ray absorption.This addresses the limitations inherent in conventional semiconductor-based detectors.In this study,simple X-ray detector imaging tests were conducted,demonstrating the excellent coupling capability between FC40 electronic fluorinated liquid and CMOS chips by the X-ray detector.A spatial resolution of 4.0 lp/mm was measured using a striped line par card,and a relatively clear image of a cockroach was displayed in the digital radiography imaging results.Preliminary test results indicated the feasibility of fabricating an X-ray detector by combining FC40 electronic fluorinated liquid and CMOS chips.Owing to the absence of issues related to chip-material coupling,a high spatial resolution could be achieved by reducing the chip pixel size.This method presents a new avenue for studies on novel liquid-based direct conversion X-ray detectors.
基金financially supported by the National Natural Science Foundation of China (62004089,62374053, 62474187 and 12235006)the Special Zone Support Program for Outstanding Talents of Henan University+4 种基金the Shenzhen Basic Research Program (JCYJ20220818101612027)the Guangdong Basic and Applied Basic Research Foundation (2024A1515012494)the Henan Province Postdoctoral Science Foundation (J23029Y)the Natural Science Foundation of Henan Province (232300420412)the Science and Technology Tackling Project of Henan Province (242102210160)
文摘Although three-dimensional metal halide perovskites are promising candidates for direct X-ray detection,the ion migration of perovskites seriously affects the detector stability.Herein,face-/edge-shared 3D heterometallic glycinate hybrid perovskitoid Pb_(2)CuGly_(2)X_(4)(Gly=-O_(2)C-CH_(2)-NH_(2);X=Cl,Br)single crystals(SCs),in which the adjacent lead halide layers are linked by large-sized Cu(Gly)_(2)pillars,are synthesized in water.The Cu(Gly)_(2)pillars in combination with face-/edge-shared inorganic skeleton are found able to synergistically suppress the ion migration,delivering a high ion migration activation energy(Ea)of 1.06 eV.The Pb_(2)CuGly_(2)Cl_(4)SC X-ray detector displays extremely low dark current drift of 1.20×10^(-9)nA mm^(-1)s^(-1)V^(-1)under high electric field(120 V mm^(-1))and continuous X-ray irradiation(2.86 Gy),and a high sensitivity of 9,250μC Gy^(-1)cm^(-2)is also achieved.More excitingly,the Pb_(2)CuGly_(2)Cl_(4)nanocrystal can be easily dispersed in water and directly blade-coated on thin-film transistor(TFT)array substrate,and the obtained Pb_(2)CuGly_(2)Cl_(4)-based TFT array detector offers an X-ray imaging capability with spatial resolution of 2.2 lp mm^(-1).
基金the China National Space Administration(CNSA)the Macao University of Science and Technology Foundation for their support of this paper。
文摘The solar X-ray detector(SXD)onboard the Macao Science Satellite-1B was designed to monitor solar flare bursts and to study the solar activity in the 25th solar cycle.The SXD includes two parts:a soft X-ray detection unit and a hard X-ray detection unit.Both the soft X-ray detection unit and the hard X-ray detection unit include two collimators,two X-ray detectors(a silicon drift detector and a cadmium-zinc-telluride detector),and a processing circuit.Compared with similar instruments,the energy range of the SXD is wider(1–600 ke V)and the energy resolution is better(150 e V at 5.9 ke V,12%at 59.5 ke V,and 3%at 662 keV).
基金supported by the project“PARIDE”(Perovskite Advanced Radiotherapy&Imaging Detectors),funded under the Regional Research and Innovation Programme POR-FESR Lazio 2014-2020(project number:A0375-2020-36698).
文摘Metal-halide perovskites are revolutionizing the world of X-ray detectors,due to the development of sensitive,fast,and cost-effective devices.Self-powered operation,ensuring portability and low power consumption,has also been recently demonstrated in both bulk materials and thin films.However,the signal stability and repeatability under continuous X-ray exposure has only been tested up to a few hours,often reporting degradation of the detection performance.Here it is shown that self-powered direct X-ray detectors,fabricated starting from a FAPbBr_(3)submicrometer-thick film deposition onto a mesoporous TiO_(2)scaffold,can withstand a 26-day uninterrupted X-ray exposure with negligible signal loss,demonstrating ultra-high operational stability and excellent repeatability.No structural modification is observed after irradiation with a total ionizing dose of almost 200 Gy,revealing an unexpectedly high radiation hardness for a metal-halide perovskite thin film.In addition,trap-assisted photoconductive gain enabled the device to achieve a record bulk sensitivity of 7.28 C Gy^(−1)cm^(−3)at 0 V,an unprecedented value in the field of thin-film-based photoconductors and photodiodes for“hard”X-rays.Finally,prototypal validation under the X-ray beam produced by a medical linear accelerator for cancer treatment is also introduced.
基金This work was supported by the National Natural Science Foundations of China(Nos.U2032170,51872228,62104194 and 51802262)The project was also supported by the Fundamental Research Funds for the Central University(3102020QD0408 and D5000210906)+1 种基金the Natural Science Foundation of Shaanxi Province(2020JC-12)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(No.2022-TS-07).
文摘In comparison to inorganic counterparts,organic semiconducting(OSC)crystalline films are promising for building large-area and flexible ionizing radiation detectors for X-ray imaging or dosimetry due to their tissue equivalence,simple processing and large-scale production accessibility.Fabrication processes,how-ever,hinder the ability to generate aligned and large-area films with high carrier mobility.In this work,the space-confined melt process is used to produce highly orientated 4HCB(4-hydroxycyanobenzene)OSC films with a large area of 15×18 mm^(2).The out-of-plane direction of the 4HCB film is<001>,and the benzene rings are found to be extensively overlapped inside the in-plane direction,according to the XRD patterns.The film exhibits a high resistivity up to 1012cm,and high hole mobility of 10.62 cm^(2)V^(−1)s^(−1).Furthermore,the 4HCB(80μm-thick film)based X-ray detectors can achieve a sensitivity of 93μC Gy air^(−1) cm^(−2)and on/offratio of 157.The device also shows steady flexibility,with no degradation in detecting function after 100 cycles of bending.Finally,the proposed 4HCB film detectors demonstrated a high-resolution X-ray imaging capability.The imaging of several materials with sharp edges(copper and polytetrafluoroethylene)has been obtained.This work has developed a fast but efficient approach for producing large-area,highly oriented OSC films for high-performance X-ray detectors.
基金supported by the China Natural Science Fund (No.52171253)Natural Science Foundation of Sichuan (No.2022NSFSC0949)。
文摘X-ray imaging technologies such as digital radiography(DR),is an important aspect of modern non-destructive testing and medical diagnosis.Innovative flexible X-ray detector technologies have recently been proposed and are now receiving increasing attention owing to their superior material flexibility compared with traditional flat-panel detectors.This work aims to study these innovative flexible X-ray detectors in terms of their effectiveness in DR imaging,such as detection efficiency and spatial resolution.To achieve this goal,first,a Monte Carlo model was developed and calibrated to an in-lab 150 kV DR imaging system containing a flat-panel X-ray detector.Second,the validated model was updated with various types of flexible X-ray detectors to assess their performance in nearly realistic conditions.Key parameters such as the detection efficiency pertaining to the crystal material and thickness were studied and analyzed across a broader energy range up to 662 keV.Finally,the imaging performance of the different detectors was evaluated and compared to that of the flat-panel detector in the 150 kV DR imaging system.The results show that the flexible detectors such as the CsPbBr3crystal detector deliver promising performance in X-ray imaging and can be applied to a wider range of application scenarios,especially those requiring accurate detection at challenging angles.
文摘A flowing gas proportional counter(FGPC)as the detector for astronomical observationin soft X-ray(0.2-3.5keV)range is calibrated on the 3WIB beamline at Beijing Synchrotron Ra-diation Facility(BSRF).The dead time,counting rate plateau curves,X-ray energy linearity,en-ergy resolution and window transparency of the FGPC have been measured.By means of a calibratedphotodiode(AXUV 100G IRD USA,calihrated in NIST)as a standard detector,the efficiency ofthe FGPC as function of photons energy has been obtained with an uncertainty between10%-18%.
文摘Just as lead-based perovskites that are hot in solar cell preparation, Bi-based perovskites have demonstrated excellent performance in direct X-ray detection, especially the Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> single crystals (SCs). However, compared with lead-halide perovskites, one challenge for the Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> SCs for X-ray detection application is that it is difficult to prepare large-sized and high-quality SCs. Therefore, how to get a large area with a high-quality wafer is also as important as Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> growth method research. Here, different anti-solvents are used for the preparation of poly-crystalline powder with the Antisolvents precipitation (A) method, as a control, High-energy ball milling (B) was also used to prepare poly-crystalline powders. The resultant two types of Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> wafer exhibit a micro-strain of 1.21 × 10<sup>-3</sup>, a resistivity of 5.13 × 10<sup>8</sup> Ω cm and a microstrain of 1.21 × 10<sup>-3</sup>, a resistivity of 2.21 × 10<sup>9</sup> Ω cm. As a result, an X-ray detector based on the high-quality Cs<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> wafer exhibits excellent dose rate linearity, a sensitivity of 588 μC·Gyairs<sup>-1</sup>·cm<sup>-2</sup> and a limit of detection (LoD) of 76 nGyair·s<sup>-1</sup>.
基金supported by the NSFC under Grant No.62474169the National Key Research and Development Program of China under Grant No.2024YFB3212200the funding from USTC under Grant Nos.WK2100000025,KY2190000003,and KY2190000006。
文摘Soft X-ray detectors play a vital role in materials science,high-energy physics and medical imaging.Cs_(2)AgBiBr_(6),a lead-free double perovskite,has gained attention for its excellent optoelectronic properties,stability,and nontoxicity.However,its fast crystallization and requirement for high-temperature annealing(>250℃)often lead to inferior film quality,limiting its application in flexible devices.This study introduces an alloying strategy that significantly improves the quality of Cs_(2)AgBiBr_(6)thin films annealed at a reduced temperature of 150℃.Devices based on the alloyed thin films exhibit an ultra-low dark current of 0.32 nA·cm^(-2)and a quantum efficiency of 725%.Furthermore,the first successful integration of Cs_(2)AgBiBr_(6)with a thinfilm transistor backplane demonstrates its superior imaging performance,indicating that Cs_(2)AgBiBr_(6)is a promising material for next-generation soft X-ray sensors.
基金funded by the China National Space Administration(CNSA)the Macao Foundationsupported by the Science and Technology Development Fund(FDCT)of Macao(Grant Nos.0014/2022/A1,SKL-LPS(MUST)-20212023,0034/2024/AMJ)。
文摘The Solar X-ray Detector(SXD)on-board the Macao Science Satellite-1B(MSS-1B)was successfully launched via the Chinese Long March-2C rocket on 21 May 2023,and commenced operations in early June of the same year.The MSS-1B/Soft X-ray Detection Units(SXDUs)employ two silicon drift detectors(SDDs),providing a wide range of energy spectra spanning from 0.7 to 24 keV.Notably,the SXDUs deliver a high-resolution capability of 0.14 keV@5.9 keV and operate with a time cadence of 1 second.Here,we perform thorough calibrations of the MSS-1B/SXDUs,employing a combination of ground experiments and simulations.In addition,quantitative analysis comparing the flux measurements obtained by the MSS-1B/SXDUs to the data collected by the Geostationary Operational Environmental Satellite(GOES),provides compelling evidence of their consistency.Furthermore,the preliminary spectral analysis results showcase the robustness and expected performance of the MSS-1B/SXDUs,unlocking their potential for facilitating the study of dynamic evolution of solar flares.Moreover,the innovative MSS-1B/Solar X-ray Detector facilitates concurrent observations of solar soft and hard X-rays,thereby making valuable contributions to the advancements in solar research.
基金support from the National Key R&D Program of China(No.2022YFB28033900)the National Natural Science Foundation of China(Nos.U24A20292 and 12204426)+1 种基金the Support Program for Scientific and Technological Innovation Teams of Higher Education in Henan Province(No.23IRTSTHN011)the Foundation of basic research for young teachers of Zhengzhou University(No.JC23549005).
文摘Lead-halide perovskites have made great advances in direct X-ray detection due to their large mobility-lifetime(μτ),strong X-ray absorption,and ease of synthesis,but the presence of toxic lead and high ionic migration severely limit their commercial applicability and operational stability.In this study,we substituted toxic Pb^(2+)with Bi^(3+)and Mn^(2+)for preparing eco-friendly two-dimensional lead-free perovskite Cs_(4)MnBi_(2)Cl_(12)single crystal(SC)by a hydrothermal method.The SC possesses smooth surface,good crystallinity,highμτ(1.8×10^(-3)cm^(2)·V^(-1)),and excellent stability.Therefore,the X-ray detector prepared with the Cs_(4)MnBi_(2)Cl_(12)SC achieved an extraordinary sensitivity of 2.1×10^(3)μC·Gyair^(-1)·cm^(-2)and a low limit-of-detection of 1.05 nGyair·s-1.Notably,the detector demonstrates remarkable operational stability,maintaining its original X-ray response even after 6 months of unsealed storage in air,and can function effectively at elevated temperatures up to 100℃,making it highly suitable for application in harsh environments.Moreover,the SC detector achieves high-resolution X-ray imaging because of its outstanding X-ray detection performance.This study not only verifies the feasibility of Cs_(4)MnBi_(2)Cl_(12)SC for high-performance X-ray detection and imaging but also provides new design for preparation of eco-friendly X-ray detectors with both high sensitivity and stability.
基金financially supported by the National Natural Science Foundation of China(62274103 and 51972194)the National Key Research and Development Program of China(2022YFB3204101)the 111 Project 2.0(BP2018013)。
文摘Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.However,the toxicity of lead in those perovskite heterojunctions limitstheir practical applications.Herein,we report the constructionof the first all-inorganic lead-free Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunctions with an area of 20×20 mm^(2)via a facile liquidphase epitaxial method through temperature-lowering crystallization.The epitaxial crystallization of the three-dimensional(3D)Cs_(2)AgBiBr_(6)SC film on a 2D Cs_(3)Bi_(2)Br_(9)SCsubstrate requires a large driving force for transitioning fromthe Volmer–Weber mode to the layer-by-layer growth modeunder a rapid cooling rate.The Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunction detector achieves a high sensitivity of1390μC Gy_(air)^(−1)cm^(−2)for 100 keV hard X-ray detection atroom temperature,which is enhanced to 2075μC Gy_(air)^(−1)cm^(−2)at 75℃,demonstrating impressive high-temperature stability.Moreover,the detector achieves a detection limit of37.48 nG_(yair)s^(−1)and excellent stability for 90 days without anyencapsulation.This work demonstrates the feasibility of usingthe epitaxial mechanism of perovskite formation on a highsurface-energy substrate for the controllable construction of a3D/2D heterojunction that significantly enhances X-ray detection performance.
基金National Key Research and Development Program of China,Grant/Award Number:2022YFE0139100NSFC,Grant/Award Numbers:T2322003,52172146,62175028+1 种基金International Cooperative Research Project of Jiangsu Province,Grant/Award Number:BZ2022008Fundamental Research Funds for the Central Universities,Grant/Award Number:2242024K40017。
文摘Substance discrimination beyond the shape feature is urgently desired for x-ray imaging for enhancing target identification.With two x-ray sources or stacked two detectors,the two-energy-channel x-ray detection can discriminate substance density by normalizing the target thickness.Nevertheless,the artifacts,high radiation dose and difficulty in image alignment due to two sources or two detectors impede their widespread application.In this work,we report a single direct x-ray detector with MAPbI_(3)/MAPbBr_(3)heterojunction for switchable soft x-ray(<20 keV)and hard x-ray(>20 keV)detection under one x-ray source.Systematic characterizations confirm soft and hard x-ray deposit their energy in MAPbI_(3)and MAPbBr_(3)layer,respectively,while working voltages can control the collection of generated charge carriers in each layer for selective soft/hard x-ray detection.The switching rate between soft and hard x-ray detection mode reaches 100 Hz.Moreover,the detector possesses a moderate performance with~50 nGy s^(-1)in limit-of-detection,~8000μC Gy^(-1)cm^(-2)in sensitivity and ~7 lp/mm in imaging resolution.By defining the attenuation coefficient ratio(μL/μH)as substance label,we effectively mitigate the influence of target thickness and successfully discriminate substances in the acquired x-ray images.
基金supported by the National Natural Science Foundation of China(22279083)Natural Science Foundation of Guangdong Province(2019A1515010783)+1 种基金Guangzhou Science and Technology Planning Project(202102010443)Songshan Lake Materials Laboratory.
文摘In recent years,two-dimensional metal halide perovskites(MHPs)have attracted increased attention for radiation detection and imaging.Their detection efficiencies are almost comparable to three-dimensional(3D)perovskites.Meanwhile,they demonstrate superior stability to 3D perovskites.The pursuit of high-quality,phase-pure and lead-free two-dimensional MHP materials and large-area fabrication capability for x-ray detectors are among the research hotspots.In this review,we first give a brief introduction of the crystallographic structure,optoelectronic characteristics and preparation methods of high-quality two-dimensional perovskites.In addition,we overview the general working principles of direct and indirect x-ray detection processes and the corresponding performance metrics from the perspective of detection and imaging.Furthermore,we provide a comprehensive discussion on the recent advances in 2D perovskite x-ray detectors and imaging devices.Finally,we pinpoint several major obstacles of 2D x-ray detectors that should be overcome in the near future.
基金supported by the National Natural Science Foundation of China(Grant No.42327802)the National Key R&D Program of China(Grant No.2022YFF0708100)。
文摘On May 21,2023,the Macao Science Satellite-1B(MSS-1B),a low-inclination,low-latitude,and high-precision scientific exploration satellite for geomagnetic fields and space environments,was successfully launched.The solar X-ray detector(SXD),one of the two major scientific payloads onboard the MSS-1B,has obtained a large amount of solar X-ray radiation data,which reveals the distribution law of the magnetic field in the low Earth orbit,as well as the coupling law of the Earth's magnetic field and the solar radiation and energy particle distributions.First,the overall design of the multi-detection-unit,broad-energy-range,small-volume,and low-power SXD was implemented to achieve the scientific objectives of the mission.Second,the technical indicators of the instrument were decomposed into various components,and the key technologies,such as collimator,processing circuit,thermal,and payload dataset designs,were reviewed.Third,the backgrounds,including electronic noise,cosmic diffuse X-ray background,and high-energy background in the Earth's radiation belts in and out of the field of view,were analyzed for the instrument.Then,the ground calibrations of the energy response,detection efficiency,and temperature-dependent peak drift of the SXD flight model were conducted.Finally,the in-orbit temperature,energy spectrum data,background,and solar flare process observation of the instrument in the in-orbit test stage are presented,verifying the instrument design,analysis,and ground calibration,providing a foundation for obtaining accurate solar X-ray radiation data,and achieving the scientific objectives of the satellite.
基金supported by the National Key R&D Program of China(Grant No.2017YFE0301300)the Hunan Provincial Innovation Foundation for Postgraduate(Grant No.CX2018B588)。
文摘A diamond film with a size of 6×6×0.5 mm^3 is fabricated by electron-assisted chemical vapor deposition. Raman spectrum analysis, x-ray diffraction and scanning electron microscope images confirm the high purity and large grain size, which is larger than 300 μm. Its resistivity is higher than 10^12 W· cm. Interlaced-finger electrodes are imprinted onto the diamond film to develop an x-ray detector. Ohmic contact is confirmed by checking the linearity of its current–voltage curve. The dark current is lower than 0.1 n A under an electric field of 30 k V cm^-1. The time response is 220 ps. The sensitivity is about 125 m A W^-1 under a biasing voltage of 100 V.A good linear radiation dose rate is also confirmed. This diamond detector is used to measure x-ray on a Z-pinch, which has a double-layer 'nested tungsten wire array'. The pronounced peaks in the measured waveform clearly characterize the x-ray bursts, which proves the performance of this diamond detector.
文摘A prototype of a two-dimensional position sensitive X-ray detector was designed and constructed for small angle X-ray scattering experiments at BSFR （Beijing Synchrotron Radiation Facility）. The detector is based on MWPC with cathode strip readout, and has a sensitive area of 200 mm×200 mm. The spatial resolution （FWHM） of about 210 μm along the anode wire direction was obtained from the ^55Fe X-ray test of the detector.
基金financially supported by the National Key R&D Program of China(2022YFB3608604)Science and Technology Major Project of Henan Province(231100230300)+3 种基金Science and Technology on Plasma Physics Laboratory(JCKYS2021212010)National Natural Science Foundation of China(U21A2070,12274373)Key Research and Development Project of Henan Province(231111232100)Natural Science Foundation of Henan Province(242300421155).
文摘Diamond is a highly suitable material for X-ray detectors that can function effectively in harsh environments due to its unique properties such as ultrawide bandgap,high radiation resistance,excellent carrier mobility as well as remarkable chemical and thermal stability.However,the sensitivity of diamond X-ray detectors needs further improvement due to the relatively low X-ray absorption efficiency of diamond,and the exploration of singlecrystal diamond array imaging still remains unexplored.In the current work,a 10310 X-ray photodetector array was constructed from single-crystal diamond.To improve the sensitivity of the diamond X-ray detector,an asymmetric sandwich electrode structure was utilized.Additionally,trenches were created through laser cutting to prevent crosstalk between adjacent pixels.The diamond X-ray detector array exhibits exceptional performance,including a low detection limit of 4.9 nGy s^(-1),a sensitivity of 14.3 mC Gy^(-1) cm^(-2),and a light-dark current ratio of 18,312,which are among the most favorable values ever reported for diamond X-ray detectors.Furthermore,these diamond X-ray detectors can operate at high temperatures up to 450℃,making them suitable for development in harsh environments.
基金supported by the National Natural Science Foundation of China(Grant No.51002116)the key R&D Program of Shaanxi Province(Grant No.2020GY-296)+2 种基金the“111 Project”of China(B14040)the National Natural Science Foundation of China(GYKP022)the Xi’an Jiaotong University Young Talent Program(LX6J0240001).
文摘All-inorganic CsPbBr_(3)single crystals have emerged as promising candidates for high-energy radiation detectors owing to their exceptional X-ray absorption capabilities,charge transport properties,and high stability.This study uses first-principles calculations to analyze the structure,band structure,and density of states of different CsPbBr_(3)phases,demonstrating that the orthorhombic phase of CsPbBr_(3)single crystals is more suitable for X-ray detector fabrication.A low-temperature solvent evaporation-induced crystallization method was used to fabricate single crystals to prevent defect introduction during phase transitions.After the introduction of NH_(4)SCN additives,the crystalline quality of the CsPbBr_(3)–NH_(4)SCN single crystals was significantly enhanced,with theμτvalue and bulk resistivity increasing to 1.3×10^(−2)cm^(2)·V^(−1)and 6.8×10^(10)Ω·cm,respectively.The ultimately fabricated CsPbBr_(3)–NH_(4)SCN single-crystal X-ray detector achieved a sensitivity level of 2,360.1μC·Gy_(air)^(−1)·cm^(−2) and a detection limit as low as 424.1 nGy_(air)·s^(−1) under an electric field of 20 V·mm−1.Overall,the experimental results provide new insights into the future fabrication of CsPbBr_(3)single-crystal X-ray detectors.
