Detection Of Gamma Radiation Research Articles

Enhancing aerial mapping with gamma radiation detection: a study in UAE

This work presents a comprehensive study on the development of a sophisticated gamma radiation detection system based on a drone-mounted gamma scintillation detector tailored for aerial mapping and radiation surveillance, aimed at generating an environmental radioactivity map within the United Arab Emirates (UAE). The project incorporates careful assembly and calibration techniques that utilize four high-resolution crystals (two CeBr3 and two Lanthanum Bromochloride crystals) to optimize detection sensitivity. Additionally, the study examines the effectiveness of a VETO system in improving the signal-to-noise ratio and reducing background. The detector system employs modern front-end and back-end electronics to digitize the signal at the outset of signal processing. The detector will be installed on a drone to facilitate thorough and effective surveys.

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.

Contrastive Machine Learning with Gamma Spectroscopy Data Augmentations for Detecting Shielded Radiological Material Transfers

Data analysis techniques can be powerful tools for rapidly analyzing data and extracting information that can be used in a latent space for categorizing observations between classes of data. Machine learning models that exploit learned data relationships can address a variety of nuclear nonproliferation challenges like the detection and tracking of shielded radiological material transfers. The high resource cost of manually labeling radiation spectra is a hindrance to the rapid analysis of data collected from persistent monitoring and to the adoption of supervised machine learning methods that require large volumes of curated training data. Instead, contrastive self-supervised learning on unlabeled spectra can enhance models that are built on limited labeled radiation datasets. This work demonstrates that contrastive machine learning is an effective technique for leveraging unlabeled data in detecting and characterizing nuclear material transfers demonstrated on radiation measurements collected at an Oak Ridge National Laboratory testbed, where sodium iodide detectors measure gamma radiation emitted by material transfers between the High Flux Isotope Reactor and the Radiochemical Engineering Development Center. Label-invariant data augmentations tailored for gamma radiation detection physics are used on unlabeled spectra to contrastively train an encoder, learning a complex, embedded state space with self-supervision. A linear classifier is then trained on a limited set of labeled data to distinguish transfer spectra between byproducts and tracked nuclear material using representations from the contrastively trained encoder. The optimized hyperparameter model achieves a balanced accuracy score of 80.30%. Any given model—that is, a trained encoder and classifier—shows preferential treatment for specific subclasses of transfer types. Regardless of the classifier complexity, a supervised classifier using contrastively trained representations achieves higher accuracy than using spectra when trained and tested on limited labeled data.

Radiological assessment of radon in groundwater of the northernmost Kashmir Basin, northwestern Himalaya.

This study investigates the radon concentration in groundwater in Kupwara, the northernmost district of the Kashmir valley. It further assesses the annual effective dose experienced by the district's diverse population-infants, children, and adults-attributable to both inhalation of airborne radon released from drinking water and direct ingestion. In addition to this, the calculation of gamma dose rate is also carried out at each of the sampling site of radon. A portable radon-thoron monitor and a portable gamma radiation detector were respectively employed to estimate the activity concentration of radon in water samples and to measure the gamma dose rate. The radon concentration was found to exhibit variability from a minimum of 2.9BqL-1 to a maximum of 197.2BqL-1, with a mean of 26.3 BqL-1 and a standard deviation of 23.3BqL-1. From a total of 85 samples, 10.6% of the samples had radon activity concentrations exceeding the permissible limits of 40BqL-1 set by the United Nations Scientific Committee on Effects of Atomic Radiations as reported by UNSCEAR (Sources and effects of ionizing radiation, 2008) and only 1.2% of the samples have radon activity concentration exceeding the permissible limits of 100BqL-1 set by the World Health Organization as reported by WHO (WHO guidelines for drinking-water quality, World Health Organization, Geneva, 2008). The mean of the annual effective dose due to inhalation for all age groups as well as the annual ingestion dose for infants and children, surpasses the World Health Organization's limit of 100μSvy-1 as reported by WHO (WHO guidelines for drinking-water quality, World Health Organization, Geneva, 2008). The observed gamma radiation dose rate in the vicinity of groundwater radon sites ranged from a minimum of 138nSvh-1 to a maximum of 250nSvh-1. The data indicated no significant correlation between the dose rate of gamma radiation and the radon levels in the groundwater. Radon concentration of potable water in the study area presents a non-negligible exposure pathway for residents. Therefore, the judicious application of established radon mitigation techniques is pivotal to minimize public health vulnerabilities.

Unveiling highly sensitive Dy3+ doped BaMgAl10O17 phosphor’s thermoluminescence trap features and temperature dependent luminescence for solid state lighting applications

This article explores the structural, morphological, thermoluminescence, and temperature-dependent emission properties of novel Dy3+ doped BaMgAl10O17(BAM-Dy) phosphors. Structural studies reveal that the phosphor has a similar structure to β-alumina. Rod-shaped interlinked surface morphology is a notable characteristic of the BAM-Dy samples. Incorporation of Dy3+ ions lead to the formation of distinct emission peaks (485 nm, 577 nm, and 635 nm) in the PL emission spectra. The effect of dopant concentration on the light output is crucial, and the highest PL intensity is observed for 1.5 mol% of Dy3+ concentration. The potential use of BAM-Dy phosphors for Gamma radiation detection and measurement is tested through thermoluminescence studies, which reveal high sensitivity, low threshold dose values, and exceptional response to low gamma doses, making them suitable for dosimetry applications. The investigation of trap parameters provides useful information about the number of traps, trapping mechanism, and trap energies, which is essential for in-depth study of synthesized phosphors for γ dosimetry application. The study of the effect of temperature on the luminescence behaviour is crucial for the application of phosphors in the light-emitting field. The BAM-Dy samples exhibit excellent thermal stability even at 210 °C, making them suitable for use in the field of White LEDs.

Calculation of efficiency and resolution of a hexagonal NaI(Tl) detector as a function of source position

Most gamma-ray scintillation detectors currently in use are made from inorganic materials that have a relatively high electron density. Quite often they are used to build multidetector systems that provide high scintillation light output. The performance of a gamma radiation detector (its detection efficiency) depends on the shape and size of the crystal, as well as on the source-to-detector geometry used. The NaI(Tl) gamma detector exhibits moderate energy resolution but relatively high gamma-ray detection efficiency and fast time response. In this work, the efficiency and resolution of a scintillation hexagonal detector are studied to optimize its response function. This type and size of scintillator were selected to construct a budget-friendly, reconfigurable, easy-to-maintain multidetector system for registering gamma-rays following fission, capture, and inelastic neutron scattering reactions, with reasonably good energy and time resolutions The research results made it possible to establish a geometric solid angle that increases the efficiency of recording gamma-ray radiation of the hexagonal NaI(Tl) scintillation probe under study.

Determination of the type of radioactive nuclei and gamma spectrometry analysis for radioactive sources

Determining the type of radioactive nuclei is the second activity after the inventory of radioactive waste in Kosovo, their location and the number of radioactive sources. Before starting any type of radioactive waste action, it is necessary to determine the content of their activity, the type of radioisotope, physical and chemical form and the risks associated with their management. The realization of this is achieved as a combination of quality assurance processes, the inventory of the radioisotope and its activity that is present in the waste, the composition of the waste material and direct measurements. This serious activity was carried out entirely in the field and was undertaken due to the lack of source certification or any other indication of their classification and activity. The process of determining the type of radioactive nuclei helps to realize a more effective characterization of them as well as to determine the path of waste management. The probability that a gamma radiation detector interacts with it to produce a pulse represents the effectiveness of the detector.

Fabrication of the optical lens on single-crystal germanium surfaces using the laser-assisted diamond turning

Single-crystal germanium, as an excellent infrared optical material, has been widely applied in X-ray monochromators, night vision systems, and gamma radiation detectors. However, how to obtain high-quality optical lenses on their surfaces still faces challenges due to their hard and brittle properties. To this end, this paper proposes the in situ laser-assisted diamond turning (ILADT) process, which is the combination of a laser heating technique and a single-point diamond turning process. The in situ laser heating technique is employed to enhance the surface quality of the workpiece material, while the single-point diamond turning process is utilized to fabricate optical lenses. Experimental results showed that optical lenses with high surface quality were successfully machined. The profile error is 0.135 μm, indicating the high machining accuracy. The surface roughness Sa of the aspheric lens is 0.909 nm, indicating the high machining quality achieved by the proposed ILADT process. Therefore, this study provides an effective approach for producing high-quality optical lenses on single-crystal germanium surfaces, which holds great promise for future applications in the manufacturing of optical lenses with exceptional quality.

Novel epoxy-bPBD-BisMSB composite plastic scintillator for alpha, beta and gamma radiation detection

A composite plastic scintillator is prepared by uniform dispersion of organic fluorophores 2-(4-Biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (b-PBD) and 1,4-bis(2-methylstyryl) benzene (Bis-MSB) in epoxy resin followed by curing at room temperature. The developed scintillator is strong blue emitter (425 nm), confirmed by 365 nm UV excited Photo luminescence and beta particle (90Sr-90Y) excited Radio-luminescence characterizations. The developed scintillator is highly transparent (~ 70%) to emitted light wavelength. Moreover, the scintillator’s blue emission is appropriate for photomultiplier tube (PMT) based scintillation measurement due to its maximum peak spectral response in blue region. Alpha, beta and gamma radiation detection were performed on PMT coupled scintillators of sizes Ø50 mm × 1 mm, Ø50 mm × 5 mm and Ø50 mm × 25 mm respectively. Pulse height spectra were recorded using 1 k Multichannel analyser (MCA) using various reference radiation sources. All scintillators demonstrated promising response to the respective radiations. Absolute detection efficiency of alpha scintillator is obtained as 32% (241Am), 86% of that of standard plastic scintillator EJ-212. Beta endpoint energy and gamma Compton edges showed linear variation w.r.t. corresponding channel numbers. Detection efficiency of beta and gamma scintillator is found to be 35.7% (90Sr-90Y) and 6.7% (136Cs) respectively. The developed scintillator has potential to be used for radioactivity contamination & gamma dose rate measurement applications.

Multi-pixel photon counter-based gamma camera with pinhole collimator to locate Cs-137 sources at high dose rates for the Fukushima nuclear power plant

The Fukushima Daiichi Nuclear Power Plant was severely damaged during the 2011 Great East Japan Earthquake. However, the ongoing decommissioning work has been limited by the complexity of the reactor's internal structure and very high radiation levels; locating radioactive sources is essential for efficient decommissioning. Conventional gamma cameras are mainly designed for low radiation dose (∼mSv/h) and using them under high radiation conditions is difficult (>Sv/h). Therefore, we developed a pinhole gamma camera with a gamma radiation detector consisting of a high-speed YGAG scintillator array and multi-pixel photon counters to locate radioactive sources at high dose rates. The gamma-ray photon signals captured by the developed two-dimensional detector array can be processed at a speed as high as >1 MHz/pixel using the developed large scale integrated circuit. Herein, we report the measurement results of an extremely high radioactivity of 137Cs (∼34 TBq) using the developed gamma camera. The gamma-ray source position was determined using an angular size of ∼4.6°, with images obtained at 2 m from the radioactive source and at a dose rate of 0.3 Sv/h. The direct gamma rays with a photoelectric peak at 662 keV and scattered component of gamma rays can be distinguished from the measured spectrum. We also characterize the imaging capability of the 137Cs depending on the detected gamma-ray energies and discuss related details.

Gamma radiation detector using Cantor quasi-periodic photonic crystal based on porous silicon doped with polymer

The measurement of patients’ dosages of radiation caused by medical diagnostics continues to be challenging. A Cantor sequence photonic crystal structure using porous silicon doped with a polymer of polyvinyl alcohol, carbol fuchsin and crystal violet (DPV) is proposed. The influence rules of geometrical and optical parameters such as the radiation doses, number of periods, porosity of porous layers, incident angle and thickness of layers are investigated using MATLAB based on the transfer matrix method. The transmittance of the Cantor sequence of a defective photonic crystal sensor under different conditions is investigated to select the optimum conditions. The proposed system recorded the accepted sensitivity of 0.265[Formula: see text]nm/Gy, FoM of 6.5[Formula: see text]Gy[Formula: see text], Q of 12,701, RS of [Formula: see text] and LoD of [Formula: see text] for gamma radiation. The suggested detector has simple design, accurate monitoring efficiency and immense potential for gamma radiation sensing.

RAD01: Development of a NUMTEK RAD01 Low-Cost, Portable Digital Gamma Radiation Detector

Additive manufacturing and open-source affordable instruction provide equal opportunities. Therefore, it is possible to quickly, compactly, and cheaply make expensive, scarce, and large devices in the previous century. The Geiger-Muller tube is used for the primary sensing component proposed and incorporates digital signal processing to ensure accurate and reliable measurement of gamma radiation. The performance of the developed detector is evaluated through experimental testing and comparisons with commercially available radiation detection devices. The results demonstrate the detector's ability to provide precise and consistent measurements while remaining cost-effective. Moreover, its portability and user-friendly interface make it suitable for various applications, including environmental monitoring, nuclear safety, personal radiation exposure assessment, and, most importantly, educational purposes. This low-cost portable digital gamma radiation detector contributes to the field of radiation detection by presenting an accessible solution that addresses the financial limitations associated with conventional gamma radiation detectors.

Измерение распределения дозы гамма-излучения с помощью дрона дискретным методом измерения

Several dose distribution maps have been created using a drone-mounted gamma radiation detector. Based on the results and the experiences gained in the experiments, the shortcomings of the system as well as the possibility for further development have also emerged. The primary objective of the development was to create a more compact, easily portable, and deployable system, but one which, in contrast with the previous ones, is more sensitive. Despite background radiation (typically 0.01 Sv/h in the testing areas), a difference of +0.009 Sv/h has reliably been detected in the experiments made so far. In this present development, this value was successfully reduced to +0.005 - +0.007 S/h. The improvement in sensitivity was achieved primarily by increasing the measurement time per point, which was realized using special flight control software. This sensitivity increases either allows higher scanning altitude (approximately +1-2m) or, in case of an identical flight device at an identical altitude, a larger survey area with one take-off. Naturally, scanning height or scanning speed can increase significantly if the activity of the searched source is high. In our experiments, we used a natural uranium mineral (Autunit) with activity far below that of artificially produced isotopes. In this series of experiments, we also covered the identification of several sources, which models the possibility of mapping active sources scattered around the site of a possible accident. The main advantage of the system developed and introduced by us over the survey procedures used in practice is that it is easy to mobilize, a large area can be surveyed at low cost without putting an operator at risk in the field. The purpose of the system is to detect the presence of the source and to localize it to such an extent that the localization can subsequently be easily specified by manual or other ground procedures. Since we do not strive for centimeter positioning accuracy, standard GPS localization is sufficient for measurements. During the measurements, the geographical coordinates are interpreted in accordance with the WGS’84 system. Additionally, the system displays the circles of latitude and longitude coordinates in the figures presented.

Decay rate changes in radioactive gamma emission as affected by 18 MeV proton cyclotron

Previous efforts to investigate changes in the decay constants of radioactive nuclides discovered that solar flares can temporarily alter radioactive decay rates. Thus, discerning whether external factors affect radioactive decay rates is vital for understanding nuclear processes. This study sought to explore the effect of neutrinos on radioactive nuclei by constructing a gamma radiation detection system that employs a radioactive source in front of a neutrino emission system. Responding to cyclotron operations, each of the four detection systems registered gamma count rate decreases. The results of this study confirm that rises in neutrino flux affected the decay rates of the examined radioactive nuclides. Here we provide significant evidence that neutrinos affect the radioactive decay process. Neutrino detection is challenging due to the minuscule absorption in a stable nucleus. However, the study found a greater probability of radionuclides interaction with the neutrino.

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).

Novel environmental monitoring detector for discriminating fallout and airborne radioactivity

Early warning networks are used for detecting abnormal radioactivity levels in the environment. State-of-the-art networks are equipped with both dose rate detectors and spectrometric stations. Current networks don’t automatically discriminate between radioactivity on the ground and in the air. A novel directional sensing gamma radiation detector utilizing a collimated phoswich scintillator was developed. The signals from the two scintillator materials are separated using a pulse shape discrimination. The separated signals are employed to determine the radioactivity concentrations on the ground and in the air assuming specific concentration distributions. Limitations related to imperfect directional sensing and dead time are discussed.

A new detector concept based on the prompt gamma radiation analysis for In vivo boron monitoring in BNCT.

The problem of boron concentration monitoring during the boron neutron capture therapy (BNCT) therapy is one of the main challenges of this type of radiotherapy and is directly related to the nature of the interaction of neutrons with mater. Among the available in vivo methods of boron monitoring positron emission tomography seems to be very promising but it requires a new boron carrier with a β+ emitter, which is not yet clinically available. An alternative solution may be the prompt gamma radiation analysis (PGRA) based on the secondary radiation emitted in the interaction of neutrons with the patient's tissues. This method requires, however, compact gamma radiation detection systems sustaining high counting rates and characterized by very good energy resolution. In this contribution, we present state-of-the-art solutions for monitoring in BNCT based on PGRA. Moreover, we describe a new concept of such a system based on position-sensitive scintillator detectors equipped with an anti-Compton shield and data analysis supported with modern artificial intelligence algorithms.

Gamma radiation detector selection for CT scanner

Three types of gamma radiation detectors associated with distributed electronics namely, NaI (Tl), HPGe and LaBr3(Ce) are compared primarily focusing on electronic noise and scattering noise. Additionally, detectors of same make, material, size and electronics are also compared. A methodology is proposed to select the most suitable detector for computed tomography (CT) among the available options. Standard deviation parameter is employed to estimate electronic noise without performing CT experiment. Kanpur theorem-1(KT-1) is used to estimate the scattering noise quantitatively after verifying its sensitivity to scattering noise. The impact of scattering noise on CT profiles is evaluated using dice similarity dice coefficient. A good resemblance between KT-1 and dice coefficient is observed. A maximum difference of 56% in scattering noise is observed when five detectors used simultaneously instead of single detector whereas a discrepancy of 85% is observed between different types of radiation detectors. As far as ease of handling, operational and capital cost is concern one has to compromise minimum 12% of accuracy in CT reconstruction if NaI (Tl) detector is used with respect to best alternative available.The proposed methodology can be applied to measurement that require minimal scattering interference data other than CT experiments. The manufacturer can add noise level of detector as a characteristic parameter in the data sheet.

A portable geometry-independent tomographic system for gamma-ray, a next generation of nuclear waste characterization

One of the main activities of the nuclear industry is the characterisation of radioactive waste based on the detection of gamma radiation. Large volumes of radioactive waste are classified according to their average activity, but often the radioactivity exceeds the maximum allowed by regulators in specific parts of the bulk. In addition, the detection of the radiation is currently based on static detection systems where the geometry of the bulk is fixed and well known. Furthermore, these systems are not portable and depend on the transport of waste to the places where the detection systems are located. However, there are situations where the geometry varies and where moving waste is complex. This is especially true in compromised situations.We present a new model for nuclear waste management based on a portable and geometry-independent tomographic system for three-dimensional image reconstruction for gamma radiation detection. The system relies on a combination of a gamma radiation camera and a visible camera that allows to visualise radioactivity using augmented reality and artificial computer vision techniques. This novel tomographic system has the potential to be a disruptive innovation in the nuclear industry for nuclear waste management.

Radiolabeling with Technetium 99m for the Diagnosis of Coronary Heart Disease in Senegal

Coronary heart disease is the leading cause of death in industrialized countries. In Africa, its prevalence is increasing in line with the westernization of lifestyles, the improvement of socio-economic conditions and the increase in life expectancy. Therefore, myocardial perfusion scintigraphy presents itself as an effective imaging technique allowing improved prevention, diagnosis and therapeutic management and monitoring of patients at risk. Our present work has exclusively focused on the early diagnosis of patients at risk in the nuclear medicine department of the Grand Yoff General Hospital (HOGIP). Our work consisted of administering a radiopharmaceutical to a patient and monitoring its fate in the body by external detection of gamma radiation using a Mediso Nucline TM gamma camera. We used vectors like sestamibi and tetrofosmin. These vectors have the particularity of having an affinity and a tropism for the myocardial tissue. These two vectors were labeled with technetium 99m (radiotracer). Indeed, these radioactive tracers attach themselves to the organ to be studied from where they emit gamma radiation captured by a gamma camera which detects the signal from this organ and reconstructs a computerized static or dynamic image. This made it possible to make a diagnosis of ischemia or myocardial necrosis in 57% of cases in women and 82.5% of cases in men in a sample of 45 patients. Thanks to the qualitative visual interpretation of the distribution of the tracer, a diagnostic aid was provided by the semi-quantitative analysis provided by the study of the polar maps (bull's eyes). This myocardial perfusion scintigraphy can be a valuable diagnostic aid, especially in our countries where income is limited.