Detection Of X-ray Radiation Research Articles

Supramolecular Rotor Assembly for the Design of a Hybrid Ferroelectric-Antiferromagnetic Multiferroic Semiconductor.

Ferroelectric (FE)-antiferromagnetic (AFM) multiferroic materials have sparked growing interest due to their huge possibilities in energy-saving, photoelectric devices, nonvolatile storage, and switches. However, realizing FE-AFM properties in a hybrid molecular material is difficult because ferroelectric and magnetic orders are commonly mutually exclusive. Here, we report an FE-AFM multiferroic semiconductor [NH4(18-crown-6)]2[Mn(SCN)4] (NCMS) by supramolecular assembly approach via molecular rotor synthon [NH4(18-crown-6)] and inorganic magnetic module [Mn(SCN)4]. Interestingly, NCMS shows good ferroelectricity with a spontaneous polarization (Ps) of 5.94 μC cm-2 higher than most crown-ether-based ferroelectrics. Especially, the realization of antiferromagnetism is for the first time in the crown ether hybrid perovskite ferroic systems. Additionally, semiconductor NCMS displays an X-ray radiation detection response with a large photo/dark current on-off ratio (197). Our study not only gives a deep insight into understanding multiferroic properties but also provides a novel and efficient approach to realizing high-performance hybrid multiferroic materials.

Constructing Organic Phosphorescent Scintillators with Enhanced Triplet Exciton Utilization Through Multi-Mode Radioluminescence for Efficient X-Ray Imaging.

The development of organic phosphorescent scintillators with high exciton utilization efficiency has attracted significant attention but remains a difficult challenge because of the inherent spin-forbidden feature of X-ray-induced triplet excitons. Herein, a design strategy is proposed to develop organic phosphorescent scintillators through thermally activated exciton release to convert stabilized spin-forbidden triplet excitons to spin-allowed singlet excitons, which enables singlet exciton-dominated multi-mode emission simultaneously from the lowest singlet, triplet, and stabilized triplet states. The resultant scintillators demonstrate a maximum photoluminescence efficiency of 65.8% and a minimum X-ray radiation detection limit of 110nGys-1; this allows efficient radiography imaging with a spatial resolution of ≈10.0 lp mm-1. This study advances the fundamental understanding of exciton dynamics under X-ray excitation, significantly broadening the practical use of phosphorescent materials for safety-critical industries and medical diagnostics.

THE COMPOSITION OF IMPURITIES AND DEFECTS IN Cd1-XMgXTe:In, NECESSARY TO ENSURE STABLE DETECTOR PROPERTIES

A model study of the promising new material Cd0.92Mg0.08Te:In, intended for X-ray and gamma radiation detectors operating at room temperature, was carried out. The paper highlights the results of quantitative studies of the influence of the content of impurities and structural defects on the electrophysical and detector properties of Cd0.92Mg0.08Te:In. An analysis of the calculated values of resistivity ρ and concentrations of free charge carriers, life time of non-equilibrium electrons τn, and holes τp, charge collection efficiency η with different composition of impurities and defects in this material at temperature T = 298 K was carried out. The optimal ranges of energy and concentration of alloying deep donor, which ensure a stable high-resistive state and acceptable values of η, are established. Compensation of cadmium vacancies with indium admixture was studied. Assumption was made regarding possibility of increasing the operating time of the detector having semi-insulating properties and great charge collection efficiency. A direction for further research has been formulated in order to clarify the nature of a suitable doping deep donor that ensures stable properties of the detector.

Direct & efficient detection of x-ray radiation using thermally evaporated 2D hybrid lead halide perovskite (BA2PbBr4)(BA=n-Butylammonium=C4H9NH3) film

This report demonstrates fast response and direct detection of x-ray radiation by thermally evaporated 2D hybrid halide perovskite (BA2PbBr4)(n-BA=Butylammonium=C4H9NH3) based film. A highly efficient pin-hole free/compact film (thickness∼1 μm), via a controlled evaporation process, has been grown to fabricate solid-state x-ray radiation detector film (typical dimension ∼1 × 1 cm2) of 2D hybrid halide perovskite BA2PbBr4 ( BAPB) material. Direct detection of x-rays is possible using this detector by simple electrical readout method, where a change in resistance occurs while exposed to x-ray radiation at ambient temperature. The detector current increases when an x-ray impinges on it and exhibits the highest sensitivity ∼1000 μC/Gy/cm2. The detector film shows fast response, exhibiting quick response-recovery time ∼ ms towards x-ray. The detector film exhibits reasonably high dark resistivity ∼ 1010Ω−cm and good mobility-lifetime ( μτ) product 3.308×10−6cm2/s. The 2D hybrid halide perovskite (BA2PbBr4) based detector can sustain an effective high electric field ∼5000 V cm−1 corresponding to 40 V operational bias. It shows very good radiation resistant towards x-ray and retains its crystal structure, as confirmed from structural data under sustained x-ray exposure. The 2D halide perovskite detector (BAPB) shows long-term stability or shelf life (∼4 months) and response is highly repeatable with less than 5% fluctuation, which is an important key performance metric for any radiation detector. This detector has good application potential in several areas like, medical imaging, security checking, etc.

Advancement in embedding Pb quantum dots into a Porous-Si matrix for superior X-ray radiation detection: An extended gate approach

This study reports on the synthesis of porous silicon (PS) and porous silicon doped with lead (PS–Pb) using an electrochemical method with a primary focus on optimizing key synthesis parameters to enhance material properties. During the synthesis, hydrofluoric acid (HF) and ethanol ratios were maintained at 4:1, which was crucial in achieving the desired structural properties. A structural analysis of the synthesized nanocomposites was conducted using Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (FESEM-EDX). This structural analysis validated the successful incorporation of lead (Pb) into the samples. Among the key aspects of this study were the evaluation of the I–V characteristics of the PS-Pb nanocomposites. Based on the findings of I–V measurements, an increase in the bias voltage was observed, which was directly correlated with an increase in measured current, indicating significant changes in electrical properties as a result of Pb doping. Furthermore, the responses of these materials to X-ray pulse irradiation under various conditions were successfully measured and compared, enhancing the understanding of their potential as radiation detectors. The optimal electrochemical conditions for synthesizing PS and Pd-PS were identified as 90 V, 100 mA, 1 s, and 100 V, 100 mA, 0.5 s, respectively. As a result of optimizing electrochemical synthesis parameters, lead-doped porous silicon (Pb-PS) exhibited a marked reduction in pore size, decreasing from an average of 420.88 nm in undoped PS to 244.54 nm in Pb-PS. This structural refinement correlated with improved electrical properties; I–V measurements demonstrated that the current response at a bias voltage of 0.3 V improved from 1.6×10−5 A to 6.23×10−4 An under identical conditions. Furthermore, these materials responded to X-ray radiation and showed enhanced sensitivity, with Pb-PS detectors achieving a lower response time and higher current under X-ray exposure compared to undoped PS. These findings open up new avenues for employing these nanocomposites in advanced applications, particularly in fields that require precise and efficient radiation detection, such as medical imaging and environmental monitoring. This work represents a significant contribution to the field, illustrating the potential of these custom-engineered materials for the advancement of modern healthcare and detection technologies.

Characterization of pure organic NTI crystals for direct x-ray detection

Accurate detection of x-ray radiation is essential for tissue equivalence detection and safety control during medical radiotherapy. Here, a promising radiation detector based on organic 1,8-naphthalimide (C12H7NO2, NTI) single crystals is proposed. NTI single crystals with dimensions of 8 × 2 × 1 mm3 were synthesized by an optimized solvent-cooling method, and the crystal structure was characterized to elucidate the anisotropy mechanism. The coplanar detector made by NTI has a leakage current of less than 0.1 pA at an electric field strength of 1 kV cm−1 and provides excellent detection of 5.49 MeV α-particles (241Am) with a full-energy peak resolution of up to 32.3%. The calculated electron mobility (μe) and electron mobility-lifetime product (μτ)e were 7.9 cm2 V−1s−1 and 1.56 × 10−6 cm2 V−1, respectively. Additionally, the detection limit of the NTI detector was 0.35 µGy s−1 in the electric field strength range of 0.2–1.0 kV cm−1 under a 20 kV x-ray beam with a high sensitivity of 56.2 μC Gy−1cm−2. Consequently, the NTI detector achieves an excellent spatial resolution of 0.8–0.9 lp mm−1 in terms of x-ray imaging capability.

Halogen-Regulated Tc and X-ray Radiation Detection in 2D Hybrid Perovskite Ferroelastic Semiconductor.

Organic-inorganic hybrid perovskites (OIHPs) have received particular attention due to their characteristic structural tunability and flexibility. These features make OIHPs behave with excellent modifications on macroscopic properties, such as ferroicity or semiconductor performances, etc. Herein, we report two 2D hybrid stibium-based halide perovskite (C3H7N)3Sb2X9 (X = Br, 1; Cl, 2) ferroelastic semiconductor possessing dual switching properties of dielectric and second harmonic generation (SHG). Notably, these two hybrids exhibit halogen-regulated ferroelasticity and semiconductor properties. There is a significant difference in Curie temperature (Tc) and X-ray radiation detection sensitivity (S), i.e., the ΔTc and ΔS are 38 K and 87 μC Gyair-1 cm-2, respectively. Meanwhile, crystals 1 and 2 do not show dark current drift in cyclic measurements of different radiation doses with stable switching ratios of 30 and 10, separately. Meanwhile, these results were proven by scientific experimental results and density functional theory (DFT) calculations. Our work presents a facile and practical method to regulate macroproperties on the molecular level, providing a new vision to develop hybrid perovskite ferroic-photoelectric materials.

ОПТИЧНА СПЕКТРОСКОПІЯ ДЕТЕКТОРНИХ ВИСОКООМНИХ МОНОКРИСТАЛІВ CdTe (111) ТА ТВЕРДИХ РОЗЧИНІВ Cd 1-x Zn x Te (х= 0,1)

Cadmium telluride is used for the manufacture of uncooled gamma radiation detectors, and solid solutions of Cd 1-x Zn x Te (x=0.1) are used for the manufacture of X-ray and gamma radiation detectors. The study of the effect of doping on the physical properties of semiconductors is relevant both for experimenters and for the theoretical substantiation of physical processes. This paper presents the results of the study of optical reflection spectra in the spectral range (0,2-1,7) . 10 -6 m and transmittance in the region of the fundamental optical transition E 0 of high-resistivity CdTe single crystals of (111) orientation with resistivity ρ = (2÷5)·10 9 Ohm∙cm doped with chlorine, as well as solid solutions of Cd 1-x Zn x Te (x = 0.1) with resistivity ρ = (5 ÷30)∙10 9 Ohm∙cm. Since the optical reflection coefficient R = f (λ) is related to the optical transmittance T = f (λ) and absorption D = f (λ) by the ratio R+T+D=1 (with the light (electromagnetic) wave scattering in the studied samples not taken into account), the absorption spectra D=1-(R+T) versus the light (electromagnetic) wavelength λ were also constructed in this work. It is determined that the energy of the fundamental optical transition E 0 of the studied materials at T = 300 K is as follows: for CdTe - 1.44 eV; and for Cd 1-х Zn х Te (x = 0.1) - 1.5 eV. The energy relaxation time of free charge carriers τ for p-CdTe (111) single crystals and Cd 1-х Zn х Te (x = 0.1) solid solutions was estimated to be 1.343-10 -14 s and 0,878·10 -14 s, respectively. The effective "optical" mobility for single crystals of p-CdTe (111) and solid solutions of Cd 1-х Zn х Te (x = 0.1) is 274 . 10 -4 ; 179,5 . 10 -4 , respectively. It has been shown that the investigated crystals are of high (detector) quality, which is crucial for the manufacture of highly sensitive and high-resolution ionising radiation sensors. The practical value of the obtained results lies in the determination of electronic and physical parameters of technically important semiconductors CdTe and Cd 1-х Zn х Te (x=0.1).

Enhanced luminescence and high stability in Gd3+-doped CsPbBr3 perovskite quantum dots glasses for X-ray detection

The highly luminescent CsPbBr3 perovskite quantum dots (PQDs) glass has shown great potential for applications in X-ray radiation. In this study, the synthesis, crystallization behavior, structural photoluminescence (PL), and X-ray excited luminescence (XEL) of new scintillation luminescent ion Gd3+-service behavior studies were conducted to evaluate the effectiveness of the Gd3+-doped PQDs glasses as X-ray scintillators. The direct band gap semiconductor property makes it suitable for successful detection of X-ray radiation and allows for efficient absorption and emission of X-ray photons, leading to enhanced scintillation performance. These findings highlight the potential of Gd3+-doped CsPbBr3 PQDs glasses as promising materials for X-ray scintillation applications.

Ellipsometry Characterisation for the Cd1-xZnxTe1-ySey Semiconductor Used in X-ray and Gamma Radiation Detectors

The study of the optical properties of the Cd1-xZnxTe1-ySey (CZTS) crystal provides a clear idea about its response to incident X-ray or gamma radiation. This is important for selecting a proper composition of CZTS to achieve superior quality and high-resolution X-ray and gamma radiation detectors at room temperature and reduce their production cost. This article’s novelty is in lowering the cost of the optical and compositional characterisation of CZTS using the ellipsometry technique. The most significant successes achieved are the composition ellipsometry model determination of CZTS based on the Effective Medium Approximation (EMA) substrate of the binary compound CdTe and ZnSe with an oxide layer of CdTe and the experimental verification that the bandgap moves to lower energies with the addition of Se.

Optimization algorithm for sandwich detectors of x-ray radiation

Optimization algorithm for sandwich detectors of x-ray radiation

Selective Photochromic Response to Low-Dose X-ray Radiation Detection in One-Dimensional Cadmium-Viologen Complexes

Photochromic viologen-based materials have emerged as one of the most promising candidates for the development of X-ray light detection applications, including medical diagnosis and treatment, environmental radiation inspection, and industrial crack detection. However, the design and construction of low-dose X-ray-sensitive complexes remains an immense challenge, especially for the in-depth dissection of their response mechanisms. Herein, by using N,N'-4,4'-bipyridiniodipropionate (CV) as functional sensitive structural units and cadmium as heavy atoms, two cadmium-viologen complexes with one-dimensional chained structures, namely, [Cd2Cl4(CV)(H2O)2]n (1) and [CdBr2(CV)]n (2), have been constructed, which exhibit a remarkable and selective photochromic response to low-dose X-ray radiation detection. Compound 1 is visually sensitive to both X-ray and UV light due to the more accessible photoinduced electron transfer (ET) pathways, while compound 2 only shows a slight color-changing process in response to UV light, in conformity with UV-vis absorbance analyses and kinetic studies. Surprisingly, compound 2 has longer ET pathways than 1, but not in response to high-energy X-ray light, seeming to contradict the previous phenomena. On further analysis, the key point in achieving X-ray-sensitive behavior should be a good balance among the electron donor-acceptor distance, intermolecular interaction, and X-ray absorbing capacity, as verified by density functional theory (DFT) and X-ray absorption strength calculations, X-ray photoelectron spectra, electron paramagnetic resonance measurements, and independent gradient model analysis. In particular, compound 1 is unprecedentedly sensitive to soft X-ray radiation, accompanied by an X-ray detection limit of as low as 2.91 Gy. These findings push forward the further development of low-dose X-ray sensing materials.

An active dose-measuring device for X-rays generated by ultra-short, ultra-intense laser pulses

Ultra-short, ultra-intense laser pulses can create extreme physical conditions for a wide range of applications in atomic and molecular physics, materials chemistry, and inertial-confinement fusion. However, laser-matter interactions can be accompanied by significant X-ray emission that introduces radiation risks to the nearby environment and personnel. It is usually to monitor the radiation dose during in high-intensity laser-target interactions with optically stimulated luminescence and thermo-luminescence devices. However, these passive methods cannot measure the radiation dose in real time, while most active dosimeters cannot accurately measure pulsed radiation doses. Here, transient pulse X-ray radiation doses are converted by CdWO4 crystals into slow signals. Because the crystals have a 14-μs luminescence decay time, they can absorb sub-nanosecond X-ray pulses and release the energy at a 100-μs rate, thus reducing the linear-response pressure of subsequent devices. A pulse detector based on a CdWO4 crystal, a phototube, and a custom signal-processing circuit was developed. Experiments were performed at the 45-TW femtosecond laser facility of the Laser Fusion Research Center. The detector deviation was less than ±20% relative to that of an ionization-chamber detector. This initially verified its feasibility for real-time pulsed X-ray radiation detection.

Towards Extended Gate Field Effect Transistor-Based Radiation Sensors: Impact of Thicknesses and Radiation Doses on Al-Doped Zinc Oxide Sensitivity

Radiation measurements are critical in radioanalytical, nuclear chemistry, and biomedical physics. Continuous advancement in developing economical, sensitive, and compact devices designed to detect and measure radiation has increased its capability in many applications. In this work, we presented and investigated the performance of a cost-effective X-ray radiation detector based on the extended gate field effect transistors (EGFET). We examined the sensitivity of Al-doped Zinc oxide (AZO) of varying thicknesses, fabricated by chemical bath deposition (CBD), following X-ray irradiation with low and high doses. EGFETs were used to connect samples for their detection capabilities. As a function of the absorbed dose, the response was analyzed based on the threshold voltage shift, and the sensitivity of each device was also evaluated. We demonstrated that thin films are less sensitive to radiation than their disk-type EG devices. However, performance aspects of the devices, such as radiation exposure sensitivity and active dosage region, were found to be significantly reliant on the composition and thickness of the materials used. These structures may be a cost-effective alternative for real-time, room-temperature radiation detectors.

Silica optical fibers for a detection of X-ray radiation

The special attention has been paid to visualization and monitoring of harmful radiation to quantify the radiation intensity and prevent the undesired exposition. For these purposes, so called radioluminescent materials are widely exploited. Special attention has been paid to the research of luminescence optical fibers, which can be used for a construction of distributed optical sensors. We present a versatile nanoparticle doping approach to Zn2+-doped silica optical fibers. Zinc oxide nanoparticles were applied into porous silica frit by a nanoparticle-doping method providing a preform which was drawn into an optical fiber. The maximum concentration of Zn2+ ions in the fiber was 0.78 at. % causing the refractive index reached the value of 1.459. The fiber outer diameter was 124.8 μm and the fiber core diameter was 14.9 μm matching the standard telecommunication dimension. The fibers exhibited a blue radioluminescence showing the emission maximum at 395 nm. The fiber properties make them worthy of investigation as sensing elements of distributed sensors of high energy radiation.

PMT Signal Transmission for Hard X-Ray Diagnostics of Future Tokamaks

A pair of a scintillator and a Photomultiplier Tube (PMT) is often used as a Hard X-Ray (HXR) radiation detector in existing tokamaks such as JET, EAST, COMPASS or ASDEX-U. Future nuclear fusion reactors such as ITER or DEMO will use more powerful magnets and confine a larger volume of hot plasma. Placement of the detectors used for plasma diagnostic will be constrained by high temperatures, magnetic fields and ionizing radiation present near the tokamak vessel. It might be necessary to move detectors away from tokamak to a safer location. This might generate problems with pulse discrimination and transmission of the signal. In the case of the ITER tokamak, sensitive electronics such as digitizers cannot be installed close to the reactor due to harsh environmental conditions. A new approach to component placement is needed to protect those devices. The PMT signal will be transmitted via an over 100 m long coaxial cable to the digitizer located in the adjacent diagnostic building. The long cables will introduce additional signal attenuation. Also, the RF noise from the tokamak environment can couple into the signal. To improve the signal-to-noise ratio a dedicated PMT amplifier with a high output range (from + 1.5 to − 11 V) was proposed.The paper presents issues with signal transmission in HXR diagnostic systems and includes a discussion on the methodology of PMT signal transmission in the conditions of the future tokamaks. A proposal of guidelines for selection of the signal chain components and design of a dedicated PMT amplifier is part of this paper.

Physical Properties of Candidate X-Ray Detector Material Rb4Ag2BiBr9.

Recently, metal halide perovskites have emerged as promising semiconductor candidates for sensitive X-ray photon detection due to their suitable bandgap energies, excellent charge transport properties, and low material cost afforded by their low-temperature solution-processing preparation. Here, we report an improved methodology for single crystal (SC) growth, thermal and electrical properties of a two-dimensional (2D) layered halide material Rb4Ag2BiBr9, which has been identified as a potential candidate for X-ray radiation detection applications. The measured heat capacity for Rb4Ag2BiBr9 implies that there are no structural phase transitions upon cooling. Temperature dependence of thermal transport measurements further suggest remarkably low thermal conductivities of Rb4Ag2BiBr9 that are comparable to the lowest reported in literature. The bulk crystal resistivity is determined to be 2.59×109 Ω·cm from the current-voltage (I-V) curve. Density of trap states are estimated to be ~1010 cm-3 using the space-charge-limited-current (SCLC) measurements. The fabricated Rb4Ag2BiBr9-based X-ray detector shows good operational stability with no apparent current drift, which may be ascribed to the 2D crystal structure of Rb4Ag2BiBr9. Finally, by varying the X-ray tube current to change the corresponding dose rate, the Rb4Ag2BiBr9 X-ray detector sensitivity is determined to be 222.03 uCGy-1cm-2 (at an electric field of E = 24 V/mm).

Growth and Characterisation of Layered (BA)2CsAgBiBr7 Double Perovskite Single Crystals for Application in Radiation Sensing

A recent publication on single crystals of two-dimensional, layered organic–inorganic (BA)2CsAgBiBr7 double perovskite (BA+ = CH3CH23NH3+) suggested the great potential of this semiconductor material in the detection of X-ray radiation. Our powder XRD measurement confirms the crystallinity and purity of all samples that crystallise in the monoclinic space group P21/m, while the single crystal XRD measurements reveal the dominant {001} lattice planes. The structure–property relationship is reflected in the lower resistivity values determined from the van der Pauw measurements (1.65–9.16 × 1010 Ωcm) compared to those determined from the IV measurements (4.19 × 1011–2.67 × 1012 Ωcm). The density of trap states and charge-carrier mobilities, which are determined from the IV measurements, are 1.12–1.76 × 1011 cm–3 and 10−5–10−4 cm2V–1s–1, respectively. The X-ray photoresponse measurements indicate that the (BA)2CsAgBiBr7 samples synthesised in this study satisfy the requirements for radiation sensors. Further advances in crystal growth are required to reduce the density of defects and improve the performance of single crystals.

The influence of Gd2O3 on shielding, thermal and luminescence properties of WO3–Gd2O3–B2O3 glass for radiation shielding and detection material

The physical, structural, optical, shielding, thermal and luminescence properties of WO3-Gd2O3–B2O3 glasses were studied in this work. The effect of WO3 replacement by Gd2O3 on radiation shielding and radiation detection potential was evaluated. The glass density increases with increasing Gd2O3 concentration and the maximum value is 5.97 g/cm3. The FTIR and XRD result confirm that the trigonal BO3, tetrahedral BO4 and tungsten complex are the main chemical groups and coorperate into the amorphous structure of glass. The optical absorption spectra exhibit the absorbance of glasses in ultraviolet and visible light region. The shielding parameters of glasses, such as mass attenuation coefficient, effective atomic number, electron density and half value layer, were investigated theoretically and experimentally. They perform a small degradation of shielding property by increasing Gd2O3 content. There is no obvious dependence of Gd2O3 concentration on glass thermal conductivity and expansion. The strong photoluminescence of [WO6]6- group with 524 nm occurred under its charge transfer excitation and under the energy transfer from excited Gd3+ ion. In the radioluminescence, WGB glasses emitted the visible light with 562 nm based on the mixed emission from [WO6]6- group and oxygen vacancy. The glass possesses the X-ray detection efficiency around 18.65% of BGO crystal. The WO3–Gd2O3–B2O3 glass with 17.5 and 27.5 mol% of Gd2O3 is a promising γ-ray shielding material at room temperature and high temperature circumstance, respectively and one with 25 mol% of Gd2O3 owns the attractive potential for the X-ray radiation detection applications.

Characteristics of X-ray and gamma radiation detectors 
 based on polycrystalline CdTe and CdZnTe films

Based on CdTe and CdZnTe detectors a number of promising devices were created, which found their application in metallurgy, in solving the problems of customs control and control of nuclear materials, as well as matrix detectors created for the manufacture of medical devices and devices for space research. Detectors, created on the basis of polycrystalline semiconductor CdTe and CdZnTe films with a columnar structure on a molybdenum substrate with a thickness d = 30150 μm, had a specific resistance p > 10^5 10^8 W-cm. The energy resolution of the CdTe and CdZnTe detectors at room temperature reached ~ 5 keV on the 59.6 keV 241Am line.