Detection Of Ionizing Radiation Research Articles

Bright Innovations: Review of Next-Generation Advances in Scintillator Engineering.

This review focuses on modern scintillators, the heart of ionizing radiation detection with applications in medical diagnostics, homeland security, research, and other areas. The conventional method to improve their characteristics, such as light output and timing properties, consists of improving in material composition and doping, etc., which are intrinsic to the material. On the contrary, we review recent advancements in cutting-edge approaches to shape scintillator characteristics via photonic and metamaterial engineering, which are extrinsic and introduce controlled inhomogeneity in the scintillator's surface or volume. The methods to be discussed include improved light out-coupling using photonic crystal (PhC) coating, dielectric architecture modification producing the Purcell effect, and meta-materials engineering based on energy sharing. These approaches help to break traditional bulk scintillators' limitations, e.g., to deal with poor light extraction efficiency from the material due to a typically large refractive index mismatch or improve timing performance compared to bulk materials. In the Outlook section, modern physical phenomena are discussed and suggested as the basis for the next generations of scintillation-based detectors and technology, followed by a brief discussion on cost-effective fabrication techniques that could be scalable.

Bright and durable scintillation from colloidal quantum shells

Efficient, fast, and robust scintillators for ionizing radiation detection are crucial in various fields, including medical diagnostics, defense, and particle physics. However, traditional scintillator technologies face challenges in simultaneously achieving optimal performance and high-speed operation. Herein we introduce colloidal quantum shell heterostructures as X-ray and electron scintillators, combining efficiency, speed, and durability. Quantum shells exhibit light yields up to 70,000 photons MeV−1 at room temperature, enabled by their high multiexciton radiative efficiency thanks to long Auger-Meitner lifetimes (>10 ns). Radioluminescence is fast, with lifetimes of 2.5 ns and sub-100 ps rise times. Additionally, quantum shells do not exhibit afterglow and maintain stable scintillation even under high X-ray doses (>109 Gy). Furthermore, we showcase quantum shells for X-ray imaging achieving a spatial resolution as high as 28 line pairs per millimeter. Overall, efficient, fast, and durable scintillation make quantum shells appealing in applications ranging from ultrafast radiation detection to high-resolution imaging.

Sensitive detection of low doses beta particles using quartz crystal oscillators

The demand for developing a cheap and novel ionizing radiation detection technique has recently increased. This work aims to establish a new detection method for β particles based on a quartz tuning fork (QTF). QTF coated and uncoated with 40 nm of aluminum (Al) were used to evaluate the system under different conditions. All samples were exposed to different doses of beta using a 90Sr β source. The results confirmed that a clear frequency shift was observed during Beta irradiation. Once the radiation source was removed, the frequency returned to normal behavior. This effect is more pronounced with the Al-coated sample due to more tensile stress caused by thermal heating induced by Beta radiation. Before and after beta irradiation, the optical properties of SiO2 wafers (quartz) were also studied using spectroscopic ellipsometry (SE) measurements. The SE results were largely consistent with the QTF resonance frequency shift results. In conclusion, experiment results proved the probability of using QTF as sensitive, accurate, and easy-to-use sensing for low-dose Beta radiation.

Flexible Biopolymer Photodetectors Based Er, Tb doped BaW[formula omitted]@CS for Enhanced Light-Sensitive Coatings

Today, the electro-optics industry is one of the world's largest manufacturing sectors today, and its growth has led to an increasing reliance on electronic equipment. Simultaneously, the significance of optical wearable detection across diverse fields, from high-energy physics to nuclear medicine and optoelectronics, cannot be overstated. Barium tungstate (BWO), a remarkable and advanced compound, has consistently piqued the interest of researchers across various domains due to its unique photoenergy properties. This study presents a novel, cost-effective approach to creating flexible ionizing radiation detectors. These detectors are constructed using pure barium tungstate fillers infused with erbium and terbium within a chitosan matrix (Er: BWO-CS, Tb: BWO-CS). Initially, we synthesized pure barium tungstate nanoparticles, incorporating erbium and terbium through a co-precipitation method, and subsequently embedded them into a chitosan biopolymer substrate. Characterization through XRD, XPS, EDX-MAP, and FTIR analyses confirmed the formation of the tetragonal barium tungstate structure, bonding, compounds, and chemical elements in the prepared composites. Through SRIM calculations, we determined the optimal thickness for these flexible nanocomposites to detect alpha particles, approximating 60–80 micrometers. The optical properties of the detectors were assessed under ultraviolet light excitation, 980nm laser irradiation, proton beam exposure, and alpha source activation. Notably, the Er: BaWO4-CS nanocomposite exhibited the best scintillation properties, highest UV sensitivity, and superior alpha particle detection efficiency (at a low activity of 643Bq). The results underscored the stability, reproducibility, and linear response of these sensors under continuous irradiation. Photo/ionoluminescence studies revealed that the doped nanocomposite showed, in comparison to the pure BWO-CS sample, the greatest visible blue-green emission at room temperature, featuring a luminescence delay time of 243 µs. Antimicrobial and cytotoxicity tests confirmed the safety of these flexible sensors, making them suitable for applications related to human health applications. Consequently, these sensors represent a promising avenue for the development of next-generation wearable and environmentally friendly sensing technologies.

Arising 2D Perovskites for Ionizing Radiation Detection.

2D perovskites have greatly improved moisture stability owing to the large organic cations embedded in the inorganic octahedral structure, which also suppresses the ions migration and reduces the dark current. The suppression of ions migration by 2D perovskites effectively suppresses excessive device noise and baseline drift and shows excellent potential in the direct X-ray detection field. In addition, 2D perovskites have gradually emerged with many unique properties, such as anisotropy, tunable bandgap, high photoluminescence quantum yield, and wide range exciton binding energy, which continuously promote the development of 2D perovskites in ionizing radiation detection. This review aims to systematically summarize the advances and progress of 2D halide perovskite semiconductor and scintillator ionizing radiation detectors, including reported alpha (α) particle, beta (β) particle, neutron, X-ray, and gamma (γ) ray detection. The unique structural features of 2D perovskites and their advantages in X-ray detection are discussed. Development directions are also proposed to overcome the limitations of 2D halide perovskite radiation detectors.

Enhanced scintillation performance of Cu-doped β-Ga2O3 single crystals grown by floating-zone method

As a booming semiconductor material, β-Ga2O3 with an ultra-wide bandgap of 4.8 eV exhibits several advantages in scintillators including high stability and low self-absorption. To further improve the scintillator performance, we grew unintentionally doped, Cu-, Fe-, Mg-, and Si-doped β-Ga2O3 substrates using the floating zone method. The 0.1 mol% Cu-doped β-Ga2O3 exhibits the highest light yield of 6957 ph MeV−1 with a good linear response, which represents better predictability and stability for the input x-ray energy. Photoluminescence shows peak emission around 425 nm under the excitation of 254 nm. All the results show that Cu-doped β-Ga2O3 makes an effective scintillator with excellent light yield, and is an alternative for the high-performance ionizing radiation detectors.

A statistical method for the assessment of metrological characteristics of reference materials

Standard reference materials of the composition and properties of substances and materials are used in both industrial and non-industrial sectors of society to ensure measurement uniformity and traceability in those types of measurements that cannot be provided using standards.
 During times of war and increased nuclear threat due to a full-scale invasion by an aggressor state, there is a need for heightened attention to the verification of ionizing radiation detection blocks, measurement channels of radiation monitoring systems, radiometers, and radiometric installations, as well as alpha, beta, and gamma radiation spectrometers.
 The aim of the paper is to demonstrate the method to evaluate the measurement uncertainty of reference materials (Europium-152 (Eu-152), Сaesium-137 (Cs-137), and Thorium-232 (Th-232)) when they are generated and calibrated according to the international regulations. The evaluation of the measurement uncertainty of a radioactive reference material with a natural half-life period is relevant and valid, considering its homogeneity properties and stability. To assess the properties, as well as the measurement uncertainty, one-variant variance analysis was performed.

Flexibility potential of Cs2BX6 (B = Hf, Sn, Pt, Zr, Ti; X = I, Br, Cl) with application in photovoltaic devices and radiation detectors

As interest in double perovskites is growing, especially in applications like photovoltaic devices, understanding their mechanical properties is vital for device durability. Despite extensive exploration of structure and optical properties, research on mechanical aspects is limited. This article builds a vacancy-ordered double perovskite model, employing first-principles calculations to analyze mechanical, bonding, electronic, and optical properties. Results show Cs2HfI6, Cs2SnBr6, Cs2SnI6, and Cs2PtBr6 have Young's moduli below 13 GPa, indicating flexibility. Geometric parameters explain flexibility variations with the changes of B and X site composition. Bonding characteristic exploration reveals the influence of B and X site electronegativity on mechanical strength. Cs2SnBr6 and Cs2PtBr6 are suitable for solar cells, while Cs2HfI6 and Cs2TiCl6 show potential for semi-transparent solar cells. Optical property calculations highlight the high light absorption coefficients of up to 3.5×105 cm−1 for Cs2HfI6 and Cs2TiCl6. Solar cell simulation shows Cs2PtBr6 achieves 22.4% of conversion efficiency. Cs2ZrCl6 holds promise for ionizing radiation detection with its 3.68 eV bandgap and high absorption coefficient. Vacancy-ordered double perovskites offer superior flexibility, providing valuable insights for designing stable and flexible devices. This understanding enhances the development of functional devices based on these perovskites, especially for applications requiring high stability and flexibility.

Toward Low-Voltage and High-Sensitivity Direct X-ray Detectors Based on Thick Bulk Heterojunction Organic Device.

Organic semiconducting materials are promising for the fabrication of flexible ionizing radiation detectors for imaging because of their tissue equivalence, simple large-scale processing, and mass production. However, it is challenging to achieve high-sensitivity detection for organic direct detectors prepared by low-cost solution processing because of the compromise between thickness and carrier transport. In this study, high-performance organic direct X-ray detectors were fabricated by building a micrometer-thick bulk heterojunction (BHJ) using poly(3-hexylthiophene-2,5-diyl) (P3HT):(6,6)-phenyl c71 butyric acid methyl ester. A 5 μm BHJ film was fabricated by drop-casting and enhanced crystallization of P3HT using binary solvents and high-boiling-point additives to improve the charge carrier mobility. Furthermore, this organic direct X-ray detector has a sensitivity of >654.26 μC Gyair s-1 and a self-powered response. Because of the architecture of the thick active layer and the energy cascade in this diode detector, it has a very low dark current of 46.26 pA at -2 V. A fast and efficient approach was developed for fabricating thick, highly mobile organic BHJ films for high-performance direct X-ray detectors. It has great potential for application in a new generation of flexible and portable large-area flat-panel detectors.

Micro/Nano Perovskite Materials for Advanced X-ray Detection and Imaging.

Halide perovskites have emerged as highly promising materials for ionizing radiation detection due to their exceptional characteristics, including a large mobility-lifetime product, strong stopping power, tunable band gap, and cost-effective crystal growth via solution processes. Semiconductor-type X-ray detectors employing various micro/nano perovskite materials have shown impressive progress in achieving heightened sensitivity and lower detection limits. Here, we present a comprehensive review of the applications of micro/nano perovskite materials for direct type X-ray detection, with a focus on the requirements for micro/nano crystal assembly and device properties in advanced X-ray detectors. We explore diverse processing techniques and optoelectronic considerations applied to perovskite X-ray detectors. Additionally, this review highlights the challenges and promising opportunities for perovskite X-ray detector arrays in real-world applications, potentially necessitating further research efforts.

Structural and Photoelectronic Properties of κ-Ga2O3 Thin Films Grown on Polycrystalline Diamond Substrates.

Orthorhombic κ-Ga2O3 thin films were grown for the first time on polycrystalline diamond free-standing substrates by metal-organic vapor phase epitaxy at a temperature of 650 °C. Structural, morphological, electrical, and photoelectronic properties of the obtained heterostructures were evaluated by optical microscopy, X-ray diffraction, current-voltage measurements, and spectral photoconductivity, respectively. Results show that a very slow cooling, performed at low pressure (100 mbar) under a controlled He flow soon after the growth process, is mandatory to improve the quality of the κ-Ga2O3 epitaxial thin film, ensuring a good adhesion to the diamond substrate, an optimal morphology, and a lower density of electrically active defects. This paves the way for the future development of novel hybrid architectures for UV and ionizing radiation detection, exploiting the unique features of gallium oxide and diamond as wide-bandgap semiconductors.

Constructing Lanthanide-Organic Complexes for X-ray Scintillation and Imaging.

The photoluminescent properties of lanthanide complexes have been thoroughly investigated; however, there have been much fewer studies showcasing their potential use in ionizing radiation detection. In this work, we delve into the photo- and radio-induced luminescence of a series of lanthanide-bearing organic-inorganic hybrids and their potential as a platform for X-ray scintillation and imaging. The judicious synergy between lanthanide cations and 2,6-di(1H-pyrazol-1-yl)isonicotinate (bppCOO-) ligands affords six new materials with three distinct structures. Notably, Eu-bppCOO-1 and Tb-bppCOO-2 display sharp fingerprint X-ray-excited luminescence (XEL), the intensities of which can be linearly correlated with the X-ray dose rates over a broad dynamic range (0.007-4.55 mGy s-1). Moreover, the X-ray sensing efficacies of Eu-bppCOO-1 and Tb-bppCOO-2 were evaluated, showing that Tb-bppCOO-2 features a lower detection limit of 4.06 μGy s-1 compared to 14.55 μGy s-1 of Eu-bppCOO-1. Given the higher X-ray sensitivity and excellent radiation stability of Tb-bppCOO-2, we fabricated a flexible scintillator film for X-ray imaging by embedding finely ground Tb-bppCOO-2 in the polydimethylsiloxane (PDMS) polymer. The resulting scintillator film can be utilized for high-resolution X-ray imaging with a spatial resolution of approximately 7 lp mm-1.

Ionizing Radiation Detection Using the Field Effect Transistor Based on Reduced Graphene Oxide

Ionizing Radiation Detection Using the Field Effect Transistor Based on Reduced Graphene Oxide

METODOLOGÍA COMBINADA DE SIMULACIÓN PARA UNA CARACTERIZACIÓN COMPLETA DE LOS EFECTOS DE LA RADIACIÓN IONIZANTE EN DISPOSITIVOS DE DETECCIÓN

Ionizing radiation detection devices have been widely used in recent years in various applications and experimental fields, such as high-energy physics, nuclear physics, and medical imaging. Detailed description of their operational properties and their characterization by means of numerical modelling, as simulations, are key issue to understand the characteristics of radiation detectors in terms of efficiency, resolution and signal-to-noise ratio, since they allow optimising parameters that will be further used. The modelling processes, as the simulations, are routinely carried out using various tools, like Monte Carlo approaches, for instance: PENELOPE, FLUKA or GEANT4 are used to study the interaction of the radiation with the detector accounting for the whole physical processes. However, transporting electron/hole pairs, as generated through the device sensor to conform the corresponding electronic signals uses tools based on the finite element method, such as TCAD (Technology Computer Aided Design), which are developed mainly to help the microelectronics industry to design products. Usually, modelling approaches for radiation transport and electronic signal production are not integrated, thus performing the simulation process by splitting the problem into successive independent phases. Within this framework, the present study proposes, implements, and reports on a novel methodology that allows combining the two approaches aimed at integrating the complete simulation, thus achieving astep-by-step integrated modelling flow to describe the interaction of ionizing radiation with the sensor along with thetransport of the generated charge to the photodiodes and, finally, to the generation of electronic signals.

Pulse area compensation approach for ballistic deficits correction in perovskite CsPbBr3 semiconductor detector

Halide perovskite CsPbBr3 semiconductor has exhibited extraordinary performance on ionizing radiation detection at room temperature in the light of excellent photoelectric properties. However, signals from the CsPbBr3 planar detector usually comprises the long rising edge due to its low hole carrier mobility, subsequently leading to severe ballistic deficits in pulse amplitudes (over 10 %) when the shaping time is inferior to rise time. To overcome this issue, the integrated pulse area approach is proposed and implemented herein to compensate the amplitudes underestimation of pulses particularly with varied rise times. It was verified that the pulse area extracted by this approach was insensitive to the rise time (when varying from 1 to 130 μs) while manifesting the relative variance below 1.49 × 10−5. Accordingly, the bivariate distribution between the integrated pulse area and rise time regarded as unaffected by ballistic deficits was finally accomplished which reflected the actual depth of individual event interactions. The approach is computationally feasible in eliminating the ballistic deficit, and is anticipated to foster the deployment of perovskite detector in radiation detection.

Isomeric fluorescence sensors for wide range detection of ionizing radiations

In order to achieve a wider range of ionizing radiations detection, novel fluorescence sensing materials have been developed that utilize the fluorescence enhancement phenomenon caused by the intramolecular photoinduced electron transfer (PET) effect. Two perylene diimide isomers PDI-P and PDI-B were designed and synthesized, and their molecular structures were characterized by high-resolution Fourier transform mass spectrometry (HRMS), nuclear magnetic resonance hydrogen and carbon spectroscopy (1H and 13C NMR). The interaction between ionizing radiation and fluorescent molecules was simulated by HCl titration. The results show that combining PDIs and HCl can improve fluorescence through the retro-PET process. Despite the similarities in chemical structures, the fluorescent enhancement multiple of PDI-B with aromatic amine as electron donor is much higher than that of PDI-P with alkyl amine. In the direct irradiation experiments of ionizing radiation, the emission enhancement multiples of PDI-P and PDI-B are 2.01 and 45.4, respectively. Furthermore, density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations indicate that the HOMO and HOMO-1 energy ranges of PDI-P and PDI-B are 0.54 eV and 1.13 eV, respectively. A wider energy range has a stronger driving force on electrons, which is conducive to fluorescence quenching. Both femtosecond transient absorption spectroscopy (fs-TAS) and transient fluorescence spectroscopy (TFS) tests show that PDI-B has shorter charge separation lifetime and higher electron transfer rate constant. Although both isomers can significantly reduce LOD during PET process, PDI-B with aromatic amine has a wider detection range of 0.118–240 Gy due to its larger emission enhancement, which is a leap of three orders of magnitude. It breaks through the detection range of gamma radiation reported in existing studies, and provides theoretical support for the further study of sensitive and effective new materials for ionizing radiation detection.

Ultrasensitive and Robust CsPbBr3 Single-Crystal X-ray Detectors Based on Interface Engineering.

Halide lead perovskites have shown great development in recent years for ionizing radiation detection. However, the bias-induced interfacial electrochemical reaction between the perovskite and electrode severely deteriorates detector performance. We report that BCP strongly interacts with Al and constructs a stable Al-BCP chelating interface, resulting in the suppression of a detrimental electrochemical reaction. The fabricated Au/Al/BCP/C60/CsPbBr3/Au detector shows a low dark current of 3 nA with a stable baseline at an extremely high bias of 100 V (∼100 V mm-1). The superior high-bias stability enables a high sensitivity of 7.3 × 104 μC Gyair-1 cm-2 at 100 V. Meanwhile, a low detection limit of 15 nGyair s-1 at 40 V is achieved due to the reduced noise. The outstanding performance of our device exceeds that of most advanced detectors based on CsPbBr3 single crystals. Besides, X-ray imaging with 1 mm spatial resolution is well demonstrated at a low dose rate of 200 nGyair s-1. The interfacial chelating strategy overcomes the technical limitation of bias-induced instability of perovskite radiation detectors and can be anticipated to operate under an extremely high electrical field.

Testing of a new ionizing radiation detector based on multimode optical fibers

"This paper presents our results investigation to evaluation effects of the electron beams radiation generated in multimode optical fibers at high irradiation doses in order to develop an ionizing radiation dosimeter. The radiation induced attenuation has been shown to exhibit a linear dependence as a function on the applied dose on a certain doses range and after the irradiation the optical fibers go through a “recovery process” during which the optical properties improve again. The surface morphological changes due to electron beam irradiation were investigated by Scanning Electron Microscopy and Atomic Force Microscopy."

A Fast, Low-Jitter, and Low-Time-Walk Multi-Channel Front-End IC for Diamond and Silicon Radiation Detectors

This paper presents the design and implementation of a radiation-hardened analog front-end (AFE) integrated circuit (IC) developed for interfacing with solid state ionizing radiation detectors, providing accurate amplitude and time-of-arrival measurements. The AFE is designed for use in the Beam Conditions Monitor Prime (BCM’) of the ATLAS experiment at the Large Hadron Collider (LHC). The proposed AFE is comprised of four channels, allowing for re-configuration to operate as either a low-noise high-gain amplifier for beam luminosity measurements, or a high-linearity low-gain amplifier for beam abort functionality. Each of the AFE channels consists of a low noise trans-impedance amplifier (TIA) optimized for minimal jitter and amplitude noise, a second stage differential amplifier, followed by a fully differential Constant Fraction Discriminator (CFD) to provide an amplitude independent time pick-off with a wide dynamic range. The CFD utilizes a new all-pass filter delay topology and high-performance zero-crossing detector to minimize time-walk. The core of each AFE channel occupies an area of 0.06 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in a 65 nm CMOS technology and consumes 57 mW, including the drivers. The measured AFE chips achieve 1 ns pulse rise time, 130 electron baseline equivalent noise charge (ENC), and <25 ps RMS jitter at 1 fC input charge. To the authors’ best knowledge, this work demonstrates the lowest published time-walk of ±6 ps across 30 dB signal dynamic range. Furthermore, irradiated AFEs are shown to tolerate up to 225 Mrad total ionizing dose with no significant degradation in measured performance characteristics.

High-performance metal halide perovskite X-ray detectors fabricated with antisolvent-assisted spray-coating

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 Gyair−1 cm−2, demonstrating its great potential for X-ray detection applications.