Gamma-ray Spectrometry System Research Articles

Use of a drone-based gamma-ray spectrometry system to assess point or extended radioactive sources

In recent times, the utilization of unmanned aerial vehicles (UAVs) has emerged as a novel tool for a wide range of tasks associated with radiological protection in hazardous situations. This article presents the development of a rotary-wing drone-based system equipped with a LaBr3(Ce) detector, enabling highly accurate quantification of both point and extended radiation sources. The drone’s capability to precisely measure H*(10) and the activity levels of the involved radionuclides has been assessed through real-world testing in two scenarios. The results demonstrate uncertainties of less than 20%.

Determination of radon concentration in bottled drinking water of Dhaka City

ABSTRACT Among all natural radiation sources, exposure to radon (222Rn) is considered as the most hazardous to human health. Recognizing the significance of water in preserving a healthy life style, assessing the 222Rn activity in drinking water is crucial. The 222Rn activity concentration was measured in 20 different branded bottled drinking waters purchased from Dhaka city using both alpha and gamma-ray spectrometry systems. Activity concentrations of 222Rn in bottled water obtained via RAD7 detector varied from 0.1 ± 0.02 Bq/L to 0.42 ± 0.01 Bq/L with an average value of 0.26 ± 0.02, while the value varied from 0.12 ± 0.01 Bq/L to 0.52 ± 0.31 Bq/L with an average value of 0.29 ± 0.09 by HPGe detector. The obtained results show lower concentrations when compared with other studies around the world as well as the US-EPA reference level of 11.1 Bq l−1 or 300 pCi l−1. The total annual effective dose calculated for different age groups and internal organ doses were found below the action level recommended by WHO (0.1 mSv y−1) and ICRP (3–10 mSv y−1), due to 222Rn, 3H and 40K in drinking water. Based on the obtained radon concentration and concomitant dose values, this study suggested negligible health hazards due to the consumption of bottled drinking water in Bangladesh. The results of this study could serve as a reference data for future studies in the area and beyond.

Estimation of Radiation Dose in Building Materials Used In Federal University Gusau Using Gamma-Ray Spectroscopy Analysis

This study estimated the radiation dose in building materials (sand, cement, and granite) in Federal University Gusau, Zamfara State, Nigeria, through gamma-ray spectrometry system using a Sodium Iodide Thallium activated "NaITl" detector in a low background configuration. The range of the average activity concentration of 226Ra was found to be 56.65±0.75Bqkg-1 to 159.45±2.68Bqkg-1, which was higher than that of the world mean value for soil 35Bqkg-1,for 232Th the range was 46.65±0.45Bqkg-1 to 79.32±1.68Bqkg-1, all the samples, were found to be higher than that of the world mean for soil 30Bqkg-1. While the activity concentrations of 232Th levels of blocks, granite, and sand samples are all above the world range, except the cement which was within the worldwide range 194.84±1.31Bqkg-1 to 656.84±0.76Bqkg-1. The average activity concentration of 40K for cement, sand, and blocks was within the worldwide range, with granite samples slightly higher than the world mean value for soil 400Bqkg-1. The results have been compared with the world mean values of 35, 30, and 400Bqkg-1 specified by the UNSCEAR (2016). Concerning radiological risk to human health, the absorbed gamma dose rate (D) was estimated to be above the world average range of 55nGyh-1; the outdoor annual effective dose equivalent (AEDE) were, estimated to be below the permissible limit of 0.07mSvy-1. The values of Raeq, Hex, and Hin for all the samples in the present work are lower than the accepted safety limit value of 370Bqkg-1 and below the limit of unity, respectively.

Determine the hazards of radioactive elements and radon gas manufacturing processes in an Egyptian fertilizer factory

This study investigated the levels of radioactivity in soil surrounding a phosphate fertilizer factory in Egypt, aiming to assess potential risks to the population exposed to radiation. Concentrations of 238U, 226Ra, 232Th, and 40K were measured in soil samples collected from two subsites: one near the factory (subsite 1) and another further away (subsite 2). Two different systems were used for measuring radioactivity, a high-purity gamma ray spectroscopy system with an HPGe detector for gamma-emitting isotopes and a CR-39 solid nuclear track detector for alpha-emitting radon gas. Subsite 1, located close to the factory, displayed significantly elevated levels of 226Ra compared to global background levels (514 and 456 Bq/kg vs. 35 Bq/kg). Additionally, the concentrations of 238U (241.06 Bq/kg vs. global average 35 Bq/kg), 232Th (16.15 Bq/kg vs. global average 30 Bq/kg), and 40K (146.36 Bq/kg vs. global average 400 Bq/kg) were all above global averages. Furthermore, a high concentration of radon gas (337.06 μSv/y) was measured at subsite 1. The strong positive correlation observed between 226Ra and 238U (0.96256) provides further evidence of potentially elevated radioactivity levels near the factory. In contrast, subsite 2, situated farther from the factory, exhibited natural radioactive background levels within international limits. Quantitative analysis revealed that gamma ray absorbed doses for 226Ra and 232Th exceeded global averages in some samples. Specifically, 226Ra doses ranged from 7.8 to 46.26 ppm (exceeding the 20 ppm global average in some cases), and 232Th doses ranged from 1.98 to 9.14 ppm (exceeding the 10 ppm global average in some cases). The concentration of 40K, however, remained within the global range (0.07%–0.69 %). The observed imbalances in the ratios of Th/U (0.17–0.24 Bq/kg and 0.73–0.24 ppm) and U/Ra (0.81–0.73 Bq/kg and 0.73–0.17 ppm), both of which are significantly lower than their respective global averages of 4 and 2.4, point towards the presence of fertilizer-derived contamination. This conclusion is further supported by the high phosphate concentrations detected in the samples. Overall, this study suggests that radioactive contamination near the phosphate fertilizer factory significantly exceeds global background levels and international limits in some cases. This raises concerns about potential risks posed to surrounding agricultural land and crops.

Radiological Impact Assessment of Natural Radionuclides and Heavy Metal Contamination in Industrial Tin-Tailing Processing Effluent

This study investigates the radiological hazard and heavy metal contamination of water effluents from Malaysian tin-tailing processing plants. Samples were collected from retention ponds in seven separate tin tailing processing plants scattered throughout the state of Perak, Malaysia. Samples were analysed for radioactivity and heavy metal concentration using Gamma-ray Spectrometry System and Inductively Coupled Plasma-Mass Spectrometry, respectively. The analysis indicates that the concentration of Radium-226 (226Ra), Radium-228 (228Ra), and Potassium-40 (40K) in samples ranged from 2.4 - 34.9 Bq/l, 0.8 - 14.7 Bq/l, and 19.5 - 299.4 Bq/l, respectively. These levels surpassed the control limits (5 Bq/l and 10 Bq/l for 226Ra and 228Ra) set by the regulatory authority. The analysis of the heavy metal contamination showed that the concentration of Arsenic (As) and Lead (Pb) werehigher than the Maximum Concentration Level (MCL) of 0.01 and 0.015 mg/L, respectively. Further evaluation of radiological impact showed that the average Annual Effective Doses (AED) by water ingestion and AED for external exposure are 1.43±0.67 mSv/y and 1.71±0.79 mSv/y, respectively. While for non-carcinogenic and carcinogenic risk assessments, the value of hazard index and lifetime cancer risk is 2.1×10-10 and 1.2×10-7, respectively. These research findings suggest that effective treatment of the effluent should be implemented before discharge into the drainage system to prevent the accumulation of radionuclides and heavy metals in the environment, which may pose a risk to public health.

Soil Measurements Using High Purity Germanium Gamma Spectroscopy for Areas Surrounding Al-Tuwaitha Nuclear Site

This study introduces the calculations of the radiation background, by characterizing the radionuclides and calculating their specific effectiveness in the environment of the city of Baghdad (soil and plants) using the gamma-ray spectroscopy technique. 20 soil samples at a depth of 20 cm were collected for 5 locations on the Rusafa side, where the site coordinates were fixed using the G.P.S device. A modern global gamma-ray spectroscopy system (DSA 2000) was used, with high-purity germanium (HPGe) detector with an efficiency of 50% and an analysis capacity of 2.2 keV with respect to the energy of 1332 keV for the 60Co source. The results of the specific activity rates of the radionuclides (214Bi or 214Pb), (228Ac or 208Tl), (40K), and (137Cs) in soil were: (50.735 Bq/kg or 0.525 Bq/kg) which is close to the value of the previously published results, as the highest value was recorded in Bangladesh (88.1 Bq/kg or 4.8 Bq/kg). The results of the qualitative effectiveness of the soil of the sites showed normal levels within the radiation background of Baghdad's soil. There was a significant convergence of the study's findings with other studies.

Natural radioactivity in select metamorphic and sedimentary rocks of the Opava Mountains (Poland): A comparison between laboratory and in situ measurements of 232Th, 238U, and 40K activities

rocks from the Opava Mountains region (Eastern Sudetes, Poland) as measured in the laboratory and under in situ field conditions. Activity concentrations for 232Th, 238U, and 40K were obtained using an HPGe gamma-ray spectrometry system. Activities for 232Th ranged from 2 to 39 Bq kg−1 as measured in the laboratory and from 5 to 38 Bq kg−1 measured under in situ field conditions. For 238U, the activity concentrations ranged from 4 to 37 Bq kg−1 in the laboratory and from 7 to 42 Bq kg−1 under in situ field conditions. For 40K, activity concentrations ranged from 12 to 820 Bq kg−1 in the laboratory and from 60 to 826 Bq kg−1 under in situ field conditions. Measured activity concentrations were compared with average activity concentrations of radionuclides in similar types of rocks from different global localities. The in situ field measurement and laboratory measurements did not show significant differences indicating that both methods provide reliable 232Th, 238U, and 40K results for different lithologies.

High-Resolution Gamma-Ray Spectrometry of Pebble Bed Reactor Fuel Using Adaptive Digital Pulse Processing

In this work, an investigation was performed to assess the feasibility of passive gamma-ray spectrometry using adaptive digital pulse processing for online interrogation of pebble bed reactor (PBR) fuel. This work incorporates the physics of the radiation emission phenomenon with advanced pulse processing techniques to develop a high-resolution gamma-spectrometry system capable of handling ultrahigh count rates in various applications of nuclear science and technology. Computational modeling was used to simulate the irradiation of PBR fuel and to design the adaptive digital pulse processing–based gamma-ray spectrometry system. Monte Carlo simulations were performed to study the gamma-ray spectra of the PBR fuel and to perform coupled photon-electron transport analysis to calculate the pulse-height spectrum of PBR fuel. A Monte Carlo computer routine was used to predict the effect of pulse pileup at high-count-rate conditions. This code utilizes the random interval distribution function based on Poisson statistics to simulate the pileup behavior. Combined with pileup logic, a recursive trapezoid filter with adaptive shaping parameters was implemented to simulate the pileup behavior of a digital gamma-ray spectrometry system. The adaptive shaping algorithm selects the rise time of the trapezoid shaping filter based on the separation between the input pulses for each incoming signal. The simulation results using the proposed adaptive digital pulse processing demonstrated that with the improved energy resolution, the burnup information can be more accurately determined on a pebble-by-pebble basis as compared to fixed shaping, and tasks related to in-core fuel management, safeguards, and waste management become feasible to perform efficiently and accurately.

Measuring radioactive content and the effective radiation doses of natural origin in most consumed foodstuffs in the city of Kut – Iraq

Natural radioactive materials known by the term (NORM) are among the most important sources of radiation that can be transmitted to humans through eating foodstuffs. Therefore, researchers took care to study the levels of this type of radiation. In the current study, the levels of radioactivity were determined for the three most important natural radioactive elements, uranium (U-238), thorium (Th-232), and potassium (K-40) in (29) of the most consumed food samples collected from Wasit Governorate Markets. A gamma-ray spectroscopy system consisting of a sodium iodide activated thallium detector (NaI)Tl with dimensions of “3×3” and electronic units attached to it was used in this study. The results obtained from the studied samples showed the concentrations of (U-238, Th-232, and K-40), the value of the annual effective dose, the equivalent concentration of radium Raeq-226, and external and internal risk factors indicated that all concentrations of the radioactive elements targeted in the study were within the permissible limits despite the discrepancy in the values of the concentrations of these elements according to the samples.

Activity Measurement of 44Sc and Calibration of Activity Measurement Instruments on Production Sites and Clinics.

44Sc is a promising radionuclide for positron emission tomography (PET) in nuclear medicine. As a part of the implementation of a production site for 44Sc, precise knowledge of the activity of the product is necessary. At the Paul Scherrer Institute (PSI) and the University of Bern (UniBE), 44Sc is produced by enriched 44CaO-target irradiation with a cyclotron. The two sites use different techniques for activity measurement, namely a dose calibrator at the PSI and a gamma-ray spectrometry system at UniBE and PSI. In this work, the 44Sc was produced at the PSI, and samples of the product were prepared in dedicated containers for onsite measurements at PSI, UniBE, and the Institute of Radiation Physics (IRA) in Lausanne for precise activity measurement using primary techniques and for the calibration of the reference ionization chambers. An accuracy of 1% was obtained for the activity measurement, allowing for a precise calibration of the dose calibrator and gamma-ray spectrometry of the two production sites. Each production site now has the capability of measuring 44Sc activity with an accuracy of 2%.

Physico-chemical Properties, Heavy-metal Contents and Radioactivity Levels in Soils around a Cement-production Facility in Ogun State, Nigeria

Abstract: The physico-chemical properties, heavy metal content and the primordial radionuclide activities in soil samples from four locations around a cement production facility were studied. The physico- chemical properties of the soil samples were determined after aqua regia (HNO3:HCl) digestion and analysis with atomic absorption spectrophotometer (AAS) Perkin Elmer Analyst 200, while the activity concentration of the radionuclides was determined by a non-destructive analysis using a computerized gamma-ray spectrometry system with high-purity germanium (HPGe). The pH and electrical conductivity in the soil were in the range of 6.57 to 7.39 and 25.5 to 462 µs cm-1, respectively. The cation-exchange capacity (meq/100 g) for Na+, K+, Ca2+ and Mg2+ were within the ranges 0.142 to 0.622, 0.145 to 1.725, 2.112 to 4.279 and 0.092 to 0.271, respectively. Lead and cadmium were each detected in only one sample. The average activity for Uranium -238, Thorium - 232 and Potassium - 40 in soil was between 3.177 ± 0.330 Bq kg-1 - 7.934±1.190 Bq kg-1, 4.201±0.429 Bq kg-1 – 10.702 ± 1.504 Bq kg-1 and 97.733 ± 2.268 Bq kg-1 – 144.926 ± 21.738 Bq kg-1, respectively. The physico-chemical properties obtained were within the range of values observed by an earlier study conducted in the area; the concentrations of the heavy metals in the soils as well as the radiological hazard indices due to the presence of naturally -occuring radionuclide materials (NORMs) in the soils were very low and are not expected to constitute any environmental hazard. Keywords: Physico-chemical properties, Radioactivity, Cement, Ewekoro, Effective dose.

Radioactive Concentrations in Chemical Fertilizers

Background: The aim of the present study was to determine radioactive concentrations in fertilizers known to contain essential nutrients. Results of this study could be used as basic data to monitor the impact of chemical fertilizers on the environment and public health. Nitrogen fertilizers, calcium fertilizers, sulfur fertilizers, phosphate acid fertilizers, and potassium chloride fertilizers were used in this study.Materials and Methods: Five chemical fertilizers were pulverized, placed in polyethylene containers, and weighed. The time to measure each specimen was set to be 3,600 seconds for a scintillator-based gamma-ray spectroscopy system. Concentration of gamma radionuclide was analyzed based on obtained spectra. At the end of the measurement, the spectrum file was stored and used to calculate radioactive concentrations using a gamma-ray spectrometer software.Results and Discussion: In the nitrogen fertilizer, 3.49 ± 5.71 Bq/kg of <sup>137</sup>Cs, 34.43 ± 7.61 Bq/kg of <sup>134</sup>Cs, and 569.16 ± 91.15 of <sup>40</sup>K were detected whereas <sup>131</sup>I was not detected. In the calcium fertilizer, 5.74 ± 4.40 Bq/kg of <sup>137</sup>Cs (the highest concentration among all fertilizers), 22.37 ± 5.39 Bq/kg of <sup>134</sup>Cs, and 433.67 ± 64.24 Bq/kg of <sup>40</sup>K were detected whereas <sup>131</sup>I was not detected. In the sulfur fertilizer, 347.31 ± 55.73 Bq/kg of <sup>40</sup>K, 19.42 ± 4.53 Bq/kg of <sup>134</sup>Cs, 2.21 ± 3.49 of <sup>137</sup>Cs, and 0.04 ± 0.22 Bq/Kg of <sup>131</sup>I were detected. In the phosphoric acid fertilizer, 70,007.34 ± 844.18 Bq/kg of <sup>40</sup>K (the highest concentration among all fertilizers) and 46.07 ± 70.40 Bq/kg of <sup>134</sup>Cs were detected whereas neither <sup>137</sup>Cs nor <sup>131</sup>I was detected. In the potassium chloride fertilizer, 12,827.92 ± 1542.19 Bq/kg of <sup>40</sup>K was and 94.76 ± 128.79 Bq/kg of <sup>134</sup>Cs were detected whereas neither <sup>137</sup>Cs nor <sup>131</sup>I was detected. The present study examined inorganic fertilizers produced by a single manufacturer. There might be different results according to the country and area from which fertilizers are imported. Further studies about inorganic fertilizers in more detail are needed to create measures to reduce <sup>40</sup>K.Conclusion: Measures are needed to reduce radiation exposure to <sup>40</sup>K contained in fertilizers including phosphoric acid and potassium chloride fertilizers.

Assessment of radiometric hazards in the Southern Industrial Zone, Jeddah City, using car-borne gamma-ray spectrometry system

Assessment of radiometric hazards in the Southern Industrial Zone, Jeddah City, using car-borne gamma-ray spectrometry system

Characterization of a Fiber Optic Radiation Sensor Prototype for Nuclear Dismantling

The use of an active measurement system to localize contamination in concrete structures of nuclear facilities offers advantages such as an easy on-site analysis within a short measurement time. A measuring system based on a scintillation crystal connected to a long optical fiber with a large diameter could satisfy the demands of a measuring system for gamma-ray spectroscopy in boreholes. This work describes the development of a gamma-ray spectroscopy system using a fiber optic radiation sensor. A prototype was built with a GAGG scintillation crystal, which could reach an energy resolution of 33% at the 662-keV gamma-ray emission energy of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">137</sup> Cs. A minimal time for the detection of a contamination of a <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">137</sup> Cs source with an activity of 21 kBq and a layer of 6-cm concrete between sensor and radiation source was determined to be under 1 min with three different evaluation methods. They were based on the decision threshold and the Kolmogorov–Smirnov test corresponding to the energy distribution and the distribution of time differences between detector events. In addition, it was possible to estimate the distance of a point-like source from the sensor by establishing a further analysis parameter comparing different energy regions of a spectrum.

Ion beam activation of natCu, natTi, natNi and measurement of product formation cross sections at low energy (&lt;10 MeV)

Abstract In this study we investigated the production cross sections of natCu(p, x)63,65Zn, natTi(p, x)48V, natNi(p, x)55Co,61Cu and natCu(α, x)66,67,68Ga, natTi(α, x)49,51Cr, natNi(α, x)63,65Zn reactions in the low energy range using the foil activation technique. The samples were activated in vacuum at 5 MV tandem (Pelletron) accelerator installed at National Centre for Physics (NCP), Islamabad, Pakistan. The reaction products were identified with the help of off-line gamma ray spectroscopy system connected with Genie 2000 software. The data analysis revealed the production of different radioisotopes that have valuable importance in monitoring charged-particle beams and medical applications. The measured results were verified by comparing them with earlier evaluated data as well as with the theoretical values given in the TENDL-library based on TALYS-1.9 code calculations.

A High-Performance Gamma Spectrometer for Unmanned Systems Based on Off-the-Shelf Components

Since the Fukushima Daiichi Nuclear Power Plant accident in March 2011, the technology available for unmanned aerial vehicles (UAVs) for radiation monitoring has improved greatly. Remote access to radiation-contaminated areas not only eliminates unnecessary exposure of civilians or military personnel, but also allows workers to explore inaccessible places. Hazardous levels of radioactive contamination can be expected as a result of accidents in the nuclear power industry or as a result of the intentional release of radioactive materials for terrorist purposes (dirty bombs, building contamination, etc.). The possibility to detect, identify, and characterize radiation and nuclear material using mobile and remote sensing platforms is a common requirement in the radiation sensing community. The technology has applications in homeland security and law enforcement, customs and border protection, nuclear power plant safety and security, nuclear waste monitoring, environmental recovery, and the military. In this work, the authors have developed, implemented, and characterized a gamma-ray detection and spectroscopy system capable of operating on a UAV. The system was mainly developed using open-source software and affordable hardware components to reduce development and maintenance costs and provide satisfactory performance as a detection instrument. The designed platform can be used to perform mapping or localization tasks to improve the risk assessment process for first responders during the management of radiological and nuclear incidents. First, the design process of the system is described; the result of the characterization of the platform is then presented together with the use of the prototype installed on a UAV in an exercise simulating a radiological and nuclear contamination scenario.

Evaluation of natural radionuclides distribution in beach sands of Cox’s bazar sea beach, Bangladesh, using multivariate statistical technique

ABSTRACT The distribution of natural series radionuclides 226Ra, 232Th and non-series 40K in the heavy mineral-rich beach sands of highly touristic areas of Cox’s Bazar sea beach has been studied. The study is made to evaluate the gamma radiation exposure to individuals with an aim to establish reference data for the presence of naturally occurring radionuclides. The present study reports the probable first attempt of detail and systematic work in the study areas for estimation of activity concentration in the recent beach sand samples. Radiometric analysis was performed using gamma ray spectroscopy system based on HPGe detector. The mean activity levels of 226Ra, 232Th and 40K in Laboni beach sands were ranged from 255.69±64.57, 336.83±93.96 and 1785.91±89.60 Bq kg-1, respectively. While in Kolatoli beach sands, the respective values were 166.42±35.99, 157.35±35.90 and 1894.42±74.07Bq kg-1, respectively. The mean values of 226Ra and 232Th concentrations in the investigated beach sands were estimated to be very much higher than the corresponding world average values and comparable to those found in high background radiation areas in the world. The heavy minerals seem to control the activity concentrations of 226Ra and 232Th in sand samples, showing some variances based on uranium and thorium bearing minerals. Various radiation health hazard indicators were found to be extremely higher when compared to the recommended values. Hence, heavy mineral-rich sands may pose a significant radiological health risk to the people. The descriptive statistics indicating the radionuclides of 226Ra, 232Th and 40K are uniformly and symmetrically distributed in the Cox’s bazar beach sand. Multivariate statistical analysis showing the radioactivity and estimated radiological parameters are strongly positively correlated with 226Ra and 232Th, while weakly correlated with 40K, signifying that radiological risk is mainly associated and controlled by the radioactivity levels of uranium and thorium series radionuclides.

Glass production using tailing of upgraded rare metal mineralization, Abu Rusheid area – Egypt for nuclear waste immobilization

Most research activities in the nuclear mining industries are directed to separation of heavy and radioactive minerals from rocks and sediments. This process is completed without utilizing tailing and mineral waste materials. Tailing materials containing radioactive wastes are considered as a major environmental problem; especially with increasing the exploration of metals and lower grade mineral deposits. In the present work, borosilicate glass could be prepared for immobilizing these nuclear wastes in the designing compositions by melting at 1200–1250 °C. NaI (TI) gamma-ray spectroscopy system was used to detect 238U, 232Th, 226Ra, and 40K concentrations in tailing materials and prepared glass to emphasize their safe dose. The produced glass was characterized by XRD, SEM, FTIR, and UV spectrophotometer. Vickers hardness and leaching properties were also studied. The results showed that compact - structured glass with high durability towards groundwater was obtained. All studied environmental parameters indicated that the glass radiation dose was lower compared to international averages, thus the glass can be safely used in nuclear waste immobilization.

Determination of natural radioactivity, hazard parameters and physico-chemical properties of soils from Palakkad-Thrissur district, Kerala, India

Assessment of natural radioactivity (226Ra, 232Th, and 40K) and related radiation hazards play an important role in human health research and have received much attention from worldwide researchers. Soil is one of the key sources of human exposure to ionizing radiations. There has recently been a growing demand for soil data and information. This study aims to assess the radioactivity concentration and related parameters in the environment of Kuthiran hills due to radionuclides in soil samples collected from various locations around the Thrissur-Palakkad Highway (NH-544) regions in Kerala state (India). The activity concentrations of soil samples were determined by a gamma ray spectrometry system consisting of a p-type HPGe detector, with relative efficiency of 40%. The mean activity concentrations of 226Ra, 232Th and 40K were found to be 47.24 Bqkg−1, 67.49 Bqkg−1, and 810.87 Bqkg−1, respectively. These values are well within the permissible range, as recommended by the UNSCEAR 2008. The soil samples with the highest activity concentrations were primarily found in the valley region. The calculated hazard indices were used to estimate the potential radiological health risk from the soil, and the dose rates associated with it are significantly lower than their permissible limit. The overall findings indicate no radiological threat to the population's health in the study area.

Gamma-ray Spectroscopy Using Inorganic Scintillator Coated with Reduced Graphene Oxide in Fiber-Optic Radiation Sensor

In this study, we developed a remote gamma-ray spectroscopy system based on a fiber-optic radiation sensor (FORS) that is composed of an inorganic scintillator coated with reduced graphene oxide (RGO) and a plastic optical fiber (POF). As a preliminary experiment, we measured the transmitted light intensities using RGO membranes of different thicknesses with different wavelengths of emitted light. To evaluate the FORS performance, we determined the optimal thickness of the RGO membrane and measured the amounts of scintillating light and gamma energy spectra using radioactive isotopes such as 60Co and 137Cs. The amounts of scintillating light from the RGO-coated inorganic scintillators increased, and the energy resolutions of the gamma-ray spectra were enhanced. In addition, the gamma-ray energy spectra were measured using different types of RGO-coated inorganic scintillators depending on the lengths of the POFs for remote gamma-ray spectroscopy. It was expected that inorganic scintillators coated with RGO in FORS can deliver improved performance, such as increments of scintillating light and energy resolution in gamma-ray spectroscopy, and they can be used to identify nuclides remotely in various nuclear facilities.