Ray Spectrometer Research Articles

A flexible bioelectrode based on IrO2–coated metallized polypropylene micromembrane

We demonstrate the fabrication of a flexible and conductive bioelectrode via the electrodeposition of IrO2 nanoparticles on a metalized polypropylene micromembrane (PPMM). The metalized PPMM is prepared by carrying out conformal electroless deposition of Au on individual polypropylene (PP) fibers of PPMM using both polydopamine and polyvinyl alcohol as the surface–modifying agents to improve the hydrophilicity of PPMM. Images from scanning and transmission electron microscopes, as well as analysis from energy dispersive X–ray spectrometer and X–ray photoelectron spectroscopy confirm the successful formation of IrO2 nanoparticles on individual PP fibers of metalized PPMM. For bio–stimulating purpose, the IrO2–coated PPMM reveals an impressive charge–storage–capacity of 54.6 mC/cm2 in cyclic voltammetry, In addition, under a symmetric bi–phasic current pulse, its charge–injection–capacity reaches 466 μC/cm2. Since the entire constituents for the IrO2–coated PPMM are bio−compatible, we envision its potential use as a bioelectrode in implantable biomedical devices.

Decay spectroscopy of Sc50 and Sc50m to Ti50

The $\beta$ decay of the isomeric and ground state of $^{50}$Sc to the semi-magic nucleus $^{50}_{22}$Ti$_{28}$ has been studied using a $^{50}$Ca beam delivered to the GRIFFIN $\gamma$-ray spectrometer at the TRIUMF-ISAC facility. $\beta$-decay branching ratios are reported to 16 excited states with a total of 38 $\gamma$-ray transitions linking them. These new data significantly expands the information available over previous studies. Relative intensities are measured to less than 0.001$\%$ that of the strongest transition with the majority of $\gamma$-ray transitions observed here in $\beta$ decay for the first time. The data are compared to shell-model calculations utilizing both phenomenologically-derived interactions employed in the ${\it pf}$ shell as well as a state-of-the-art, ${\it ab~initio}$ based interaction built in the valence-space in-medium similarity renormalization group framework.

The Scientific Value of a Sustained Exploration Program at the Aristarchus Plateau

Abstract The Aristarchus plateau hosts a diversity of volcanic features, including the largest pyroclastic deposit on the Moon, the largest sinuous rille on the Moon, and intrusive and extrusive examples of evolved, Th-rich silicic lithologies. We provide an overview of previous remote-sensing measurements of the Aristarchus plateau and provide new analyses of Diviner Lunar Radiometer thermal IR data, Lunar Prospector Gamma Ray Spectrometer Th data, Chang’e-5 Microwave Radiometer data, and hyperspectral and multispectral visible/near-infrared images and spectra from the Chandrayaan-1 Moon Mineralogy Mapper and the Kaguya Multispectral Imager. The rich diversity of volcanic features on the Aristarchus plateau presents an opportunity for a sustained science and exploration program. We suggest a series of missions to the Aristarchus crater floor or ejecta, the Cobra Head, and Herodotus Mons to investigate the link between pyroclastic, effusive basaltic, and silicic volcanism in the region. Such missions would enable analyses of silicic rocks that are rare in the Apollo sample collection and demonstrate in situ resource utilization of FeO- and H2O-bearing pyroclastic materials.

Neutron activation analysis of archeological artifacts using the ISIS pulsed neutron source

Archeological artifacts can be analyzed after neutron irradiation at the pulsed ISIS neutron and muon source, UK, using a newly installed high purity germanium gamma ray spectrometer to perform neutron activation analysis. In this work, the details of the measurement methods and data analysis are presented. In particular, it is explained how Monte Carlo calculations are necessary to evaluate the detection efficiency, taking into account self-shielding effects. The results for two certified bronze standards are presented. The good agreement between expected and measured compositions is promising for the use of this technique for archeological artifacts where the elemental concentration is often unknown. As an example, the analysis of a Chinese sword from the first or second century BC is presented.

Development and characterization of a mobile γ spectrometer and its field deployment for in situ radioactivity measurements

A mobile γ–ray spectrometer (AMESOS) has been developed using a 3”×3” NaI(Tl) detector, a custom–made mounting holder, and portable electronics to perform in situ measurements of radioactivity. The spectrometer was calibrated using standard point sources and its absolute efficiency was determined. As a field test operation, AMESOS was deployed on the premises of the University of Athens Zografou campus focusing on estimating the NORM levels. Data were analyzed and used to create radiological maps for the metropolitan UoA campus for the first time. Besides natural radioactivity levels, trace concentrations of 137Cs were also detected, attributed to the Chernobyl fallout in Greece. An overall steady performance of the spectrometer was observed throughout the field operation. AMESOS is ready to be deployed for in situ studies of environmental radioactivity and radwaste management.

Origin of S-, A- and I-Type Granites: Petrogenetic Evidence from Whole Rock Th/U Ratio Variations

The origin and evolution of granites remain a matter of debate and several approaches have been made to distinguish between different granite types. Overall, granite classification schemes based on element concentrations and ratios, tectonic settings or the source rocks (I-, A-, S-type) are widely used, but so far, no systematic large-scale study on Th/U ratio variations in granites based on their source or tectonic setting has been carried out, even though these elements show very similar behavior during melting and subsequent processes. We therefore present a compiled study, demonstrating an easy approach to differentiate between S-, A- and I-type granites using Th and U concentrations and ratios measured with a portable gamma ray spectrometer. Th and U concentrations from 472 measurements in S- and I-type granites from the Variscan West-Bohemian Massif, Germany, and 78 measurements from Neoproterozoic A-type Malani granites, India, are evaluated. Our compendium shows significant differences in the average Th/U ratios of A-, I- and S-type granites and thus gives information about the source rock and can be used as an easy classification scheme. Considering all data from the studied A-, I- and S-type granites, Th/U ratios increase with rising Th concentrations. A-type granites have the highest Th/U ratios and high Th concentrations, followed by I-type granites. Th/U ratios in S- to I-type granites are lower than in A-type and I-type granites, but higher than in S-type granites. The variation of Th/U ratios in all three types of granite cannot be explained by fractional crystallization of monazite, zircon and other Th and U bearing minerals alone, but are mainly due to source heterogeneities and uranium mobilization processes.

Development of the Multi-Cubic [formula omitted]-ray spectrometer and its performance under intense 137Cs and 60Co radiation fields

The number of nuclear facilities being decommissioned has been increasing worldwide, in particular following the accident of the Tokyo Electric Power Company Holdings’ Fukushima Daiichi Nuclear Power Station in 2011. Large amounts of radioactive wastes and spent nuclear fuels are stored in these facilities. Furthermore, advanced radiation therapies such as proton therapy, ion therapy, and boron neutron capture therapy using charged-particle accelerators have become popular, but charged-particle accelerators generate radiators during operation. In these nuclear and radiation facilities, proper management of radioactive materials is required until the end of the deactivation, cleanup, or disposal. Then, γ-ray spectroscopy techniques have been useful tools because they can obtain significant information on radioisotopes. Besides, space information of radioisotopes is also important, and γ-ray imaging is also required. However, intense radiation fields are located at these facilities, causing γ-ray spectroscopy and imaging difficultly. A γ-ray spectrometer with four segmentations using small-volume CeBr3 scintillators with a dimension of 5×5×5 mm3 was developed. The four scintillators were coupled to a multi-anode photomultiplier tube specific to intense radiation fields by individual supplied voltages to the last three stages. We performed the γ-ray exposure to the spectrometer under 137Cs and60Co radiation fields at the National Institute of Advanced Industrial Science and Technology in Japan. Under the 137Cs radiation field, the relative energy resolution at 1375 mSv/h was 9.2 ± 0.05%, 8.0 ± 0.08%, 8.0 ± 0.03%, and 9.0 ± 0.04% for the four channels, respectively. As the dose rate increased, significant spectral downward shifts were observed for the four channels under the 137Cs and60Co radiation fields because of the space charge effects in the photomultiplier tube. However, the Multi-Cubic sensor could provide the total throughput rate for the four channels of greater than 6 Mcps (Mcps: 106 counts per second), which increases the detection efficiency under intense radiation fields.

Assessment of Radioactivity Contents and Radiological Effects of Marble, Granite, and Ceramic Used in Alexandria City, Egypt

The main aims of the present study are to analyze and internationally comparing the radioactivity contents of (226Ra, 232Th, and 40K) in marbles, granites, and product and raw materials of ceramics utilized in different construction purposes in Alexandria city, additionally, the associated radiological hazard indices have been assessed. Measurements have been performed by using high-resolution gamma rays spectrometer equipped with (HPGe) detector. The mean levels of the radioactivity of (226Ra, 232Th, and 40K) in marbles were 26.87, 4.30 and 19.13 Bqkg-1; respectively, and in granites were 42.90, 58.40, and 933.36 Bqkg-1; respectively, while in ceramic were 47.73, 66.09, and 385.59 BqKg-1; respectively. Results of ceramic raw materials showed the highest levels for 226Ra and 232Th as 16307.46, and 1738.69 Bqkg-1 both are recorded in zirconium, while the highest of 40K as 1760.62 Bqkg-1 in feldspar. Radiological hazards were assessed by radium equivalent activity, external and internal radiation hazard indices as well as the annual effective dose. The maximum values of indices were observed in Baltic Brown granite samples to be 425.92 Bqkg-1, 1.15, and 1, 48 for radium equivalent, external and internal hazard indices; respectively. The observed highest external effective doses in marble, granite, and ceramic were 396.53, 2109.81, and 1495.06 µSvy-1; respectively. From the obtained results is clear that granite may pose health risks as well, additional regulating the amount of zircon adding to ceramic industries is highly required.

Possible Non‐Mare Lithologies in the Regolith at the Chang’E‐5 Landing Site: Evidence From Remote Sensing Data

AbstractThe Chang’E‐5 (CE‐5) mission returned a total of 1,731 g of lunar regolith from the northern Oceanus Procellarum (NOP). Despite that the CE‐5 landing site is covered by Eratosthenian‐aged mare basalts, non‐mare lithologies might also have been collected owing to the lateral mixing introduced by nearby craters. Here we employed FeO and thorium abundance data obtained by the Lunar Prospector Gamma Ray Spectrometer to investigate the chemical composition of the NOP region. Four major compositional groups (feldspathic highland materials, Imbrium basin ejecta, Aristarchus ejecta, and mare basalts) and several subgroups have been identified. Their corresponding geographical locations were constrained using an interactive scatter‐plot tool in ENVI® software. We also determined the first‐order mixing trends occurring within the NOP region as well as the CE‐5 landing site. Aristarchus crater may have contributed highly evolved materials to the CE‐5 site. Rock fragments derived from Aristarchus ejecta are important for the interpretation of magmatic differentiation and non‐mare volcanism on the Moon. We proposed that thorium enrichments of CE‐5 landing site are due to the geochemical nature of local mare basalts rather than impact mixing. Highland ejecta, along with mare basalts, would expand Apollo and Luna sample collection diversity.

DNA Damage Detection after Chronic Exposure and Radio-adaptive Response of Naturally Occurring Radioactive Materials (NORM)

The objective of this study was to understand the effect of chronic low-dose radiation that induces in vivo radio-adaptive response. The animals were exposed chronically to natural radioactive materials (NORM) for one and two months which correspond to 10 &20 mSv which are comparable to the reality of areas with high background natural radiation (HBNR). Radioactivity assessment of samples was done using a high purity germanium -ray spectrometer. We conduct the study to understand the radio-adaptive response by exposure the experimental animals to challenge dose 2 Gy after continuous exposure to 10 & 20 mSv. Comet assay was performed in addition to some of antioxidant enzymes concentrations (superoxide dismutase (SOD), catalyze enzyme (CAT), reduced and oxidized glutathione (GSH). Chronic exposure to 10 and 20 mSv showed DNA damage as a high elevation in comet assay, parameters. Also the results of the present work showed a low production of antioxidant enzymes CAT, SOD & GSH in both chronic exposure (10 & 20 mSv and challange dose 2 Gy). The exposure to 20 mSv before 2Gy gamma rays resulted in an enhancement of antioxidant enzymes accompanied with decreasing in free radical which is represents as an adaptive response. . It can be said that for low radiation doses, which are less than 100 mSv, their effects differ from high doses, so that it can be said that the body has an adaptive response and the application of the linear non-threshold model must be reviewed for these doses.

Measurements of Radioactivity Concentrations in Granites and Sedimentary- Rocks and their Leaching Components in Egyptian Deserts


 
 
 Concentrations of radionuclides in sediments and granite samples were determined by γ- ray spectrometer using High Pure Germanium Detector; HPGe, with a specially designed shield. Six different rock samples were collected from different sites: four samples of sediments from Um Bogma southwest Sinai, and two granite samples from Gabal Gattar, the northern part of the East- ern Desert of Egypt, where all samples were subject to investigation. Their samples were selected because the activity before being dissociated in sulfuric acid was less than after dissociation. The samples were dissolved in sulfuric acid with the same parameters of solid to liquid ratio; S/L, acid concentration, and leaching time. After the leaching process, the pregnant solution was separated from the residual, and the latter was dried. The two units, named the pregnant solutions and residu- als, were also measured radiometrically using the HPGe detector to determine the activity concen- trations (Bq/kg) of the different radionuclides of the six samples. The results showed that the rela- tion between the sum of activities of both pregnant solutions and residuals with the originals have different categories. In the sediment samples; the activity of solution+ residual was 72.37% from the original of siltstone, the activity of solution + residual was 90.02% from the original claystone sample, the activity of solution + residual was 92.6% from the original of shale, the activity of solu- tion + residual was 74.07% from the original claystone. In the granite samples, the activity of solu- tion + residual was 130.39% from the original of the first granite sample and 142.3% from the orig- inal of the second granite sample. This phenomenon varied in magnitude due to the different radio- nuclides in each sample. These variations depend mainly on the nature of the grain surfaces in the different rock types and their Pb content. As for leachability analysis, leaching experiments have been performed using sulfuric acid. The leaching efficiency (%) of uranium is estimated by the measurements of the HPGe detector. The result showed almost constant values for leachability. The non-frequent appearance of attenuation of gamma activities during leaching processes indicates that the acid solutions may have led to clean the grain surfaces and thus permit gamma activities of the inner grains to be measured. The treatment of the samples before measurements may have been needed.
 
 

Estimation of 222Rn, 220Rn exhalation rate and 226Ra, 232Th, 40K radionuclides in the soil samples of different regions of Gurdaspur district, Punjab

Soil is the main source of concentration of radon and thoron gases in the indoor environment. The level of radon and thoron concentration mainly depends upon the radium, thorium contents and radon exhalation, thoron exhalation from the soil. The exhalation rate is the primary index to estimate the natural radioactivity potential of soil. The radium, thorium and potassium activity concentration were analyzed by NaI (Tl) gamma ray spectrometer. Radon and thoron surface exhalation rates were determined by scintillation-based detector SMART RnDuo Portable Radon Monitor. The geometric mean value of radon mass exhalation rate is 1.3 mBqkg-1h−1 and thoron surface exhalation rate is and 951.5 mBqm-2s−1. The geometric mean values of activity concentration of 226Ra, 232Th and 40K were 30.3 Bqkg−1, 45.8 Bqkg−1 and 339.9 Bqkg−1 respectively. The Radium equivalent activity concentration for all the soil samples was below the level of 370 Bqkg−1, recommended for building materials, by OECD 1979 (Organization for Economic Cooperation and Development).

In situ characterization using natural radio-tracers in a submarine freshwater spring, Kiveri, Greece

A medium resolution underwater gamma ray spectrometer was deployed in the submarine groundwater spring of Anavalos and was combined with conductivity and temperature sensors for continuous measurements of natural radioactivity, salinity and water temperature, respectively. The activity concentrations of radon progenies varied from (5–40) kBq m−3, exhibited reverse dependence with salinity and were found above the guideline proposed by Environmental Protection Agency (11 kBq m−3). Their ratio was above unity indicating radon gas escape to the atmosphere. Time-series of the activity concentration together with their ratios were provided enabling the system configuration for long term monitoring applications. The in-situ method proved to be an effective tool to study the radioactivity levels of the spring and the groundwater – seawater interaction process. Furthermore, the proposed tool provides cost-effective measurements in terms of real-time and long-term requirements and, it is characterized by flexibility in terms of sensor integration in different platforms to perform submarine groundwater studies in a temporal and spatial manner.

Natural radionuclide and radiological impact assessment of teak plantation, University of Ilorin, Kwara State

The amount of naturally occurring radionuclide in Teak plantation was measured using gamma ray spectrometer RS-125. This device gave an in-situ measurement of radioactivity concentration of 40K, 232Th, 238U and dose rate. The data was taken in 20 locations, the overall mean dose rate (DR) is 47.8150 Gyh−1. The overall mean activity concentrations for 40K, 232Th, 238U are 456.1975 BqKg−1, 29.0245 BqKg−1 and 26.2080 BqKg−1 respectively. It was also observed that only the estimated outdoor dose rate D of 40K at study location L1 exceeded the world limit of 57nGyh−1. This could be due to its closeness to the university main gate with lots of possible interfering human activities around the gate area. However, further study on detailed geochemical investigation is required to reach at some conclusion. By comparing the mean values of the activity concentrations and their radiological risks with the several world standards, it can be concluded that the Teak plantation is highly rich in Potassium.

Gamma Ray Spectrometric Analysis of Sand Samples from Selected Beaches along Kenyan Coastline.

In this study, the activity concentration levels of 238U, 232Th, and 40K in sand samples collected from Shanzu, Nyali, Kenyatta, Tiwi, Shelly, and Diani beaches selected along the Kenyan coastline were determined using a gamma ray spectrometer with a NaI(Tl) detector. The average activity concentrations of 238U, 232Th, and 40K in sand samples were analyzed as 87 ± 4, 98 ± 4, and 1254 ± 62 Bq/kg, respectively. Also, radium equivalent (Raeq) activity and internal (Hin) and external (Hex) hazard index were calculated to assess the radiological hazards associated with the use of sand samples as building materials. The average values of Raeq, Hin, and Hex were found as 327 ± 16 Bq/kg, 0.98, and 0.72, respectively. The average values of outdoor and indoor annual effective dose rates were estimated as of 0.23 and 0.63 mSv/y, respectively, which are below maximum recommended limit of 1 mSv/y. Generally, these results indicate no significant radiological health hazards for the studied beaches.

Assessment of Natural Radioactivity and Radiological Risks in River Sediments from Calabria (Southern Italy)

This study was developed to carry out a comprehensive radiological assessment of natural radioactivity for river sediment samples from Calabria, southern Italy, and to define a baseline background for the area on a radiation map. In the studied area, elevated levels of natural radionuclides are expected, due to the outcropping acidic intrusive and metamorphic rocks from which the radioactive elements derive. To identify and quantify the natural radioisotopes, ninety river sediment samples from nine selected coastal sampling points (ten samples for each point) were collected as representative of the Ionian and the Tyrrhenian coastline of Calabria. The samples were analyzed using a gamma ray spectrometer equipped with a high-purity germanium (HPGe) detector. The values of mean activity concentrations of 226Ra, 232Th and 40K measured for the studied samples are (21.3 ± 6.3) Bq kg−1, (30.3 ± 4.5) Bq kg−1 and (849 ± 79) Bq kg−1, respectively. The calculated radiological hazard indices showed average values of 63 nGy h−1 (absorbed dose rate), 0.078 mSv y−1 (effective dose outdoors), 0.111 mSv y−1 (effective dose indoors), 63 Bq kg−1 (radium equivalent), 0.35 (Hex), 0.41 (Hin), 0.50 (activity concentration index) and 458 µSv y−1 (Annual Gonadal Equivalent Dose, AGED). In order to delineate the spatial distribution of natural radionuclides on the radiological map and to identify the areas with low, medium and high radioactivity values, the Surfer 10 software was employed. Finally, the multivariate statistical analysis was performed to deduce the interdependency and any existing relationships between the radiological indices and the concentrations of the radionuclides. The results of this study, also compared with values of other locations of the Italian Peninsula characterized by similar local geological conditions, can be used as a baseline for future investigations about radioactivity background in the investigated area.

Investigation and correlation of radioactive hazards with magnetic parameters and heavy metals of dwelling sand from two major rivers in south India – A comparative study

Cauvery and Palar, two major rivers in Tamilnadu, India, have importance for irrigation, drinking, electricity and river sand is used as a major material of building construction in India. The natural radionuclides such as uranium, thorium and potassium (238U, 232Th, 40K) isotopes are investigated through gamma ray spectrometer with NaI(Tl) detector. The average values of radionuclides and in-situ dose are measured. Related parameters like absorbed dose (ADin & ADout), Annual Effective Doe Equivalent (Ein & Eout), and also hazard indices to assess radiation exposure to human such as average radium equivalent (Raeq), external (Hex)and internal (Hin) hazard indices, Radioactive heat production (RHP), internal and external Excess Lifetime Cancer Risk (ELCRin and ELCRout), Alpha (Iα), Gamma Index (Ig) and Annual Gonadal dose (AGDE) are computed and correlated. This study exhibits that almost all the radioactive parameters are in control by comparing to the world average. Nevertheless, the Cauvery River except site no.20 does not produce a radiological hazard. But, the palar river does slightly produce a radiological risk especially site no.6 shows three times of the world average.

Radiological environmental studies of Al Aziziah area and vicinity, Al Madinah Al Monawarah, Saudi Arabia.

The Al Aziziah area is built on volcanic and granitic rocks. The igneous rocks always contain a high amount of naturally radioactive elements such as uranium, thorium and potassium, which produce gamma rays causing environmental hazards when exceeding the permissible limit. Radon gas is a result from the decomposition of uranium/thorium leaks into enclosed areas (e.g. homes or offices). This leakage is controlled by many conditions, and one of them is the underlining rock type. To work on such an environmental study, a gamma ray spectrometer survey was used. The uranium, thorium and potassium contents, as well as their ratios and the total radiation, were determined and mapped. The radiation dose rate was calculated and mapped in mSv/y and nGy/h units. The radiation contamination of groundwater is detected from the contour map of the dose rate over the artificial drainage lines of rains and floods which move this water to the groundwater wells. The main results are as follows: granitic rocks show an average dose rate of about 2.4mSv/y, while the deposits of these rocks have an average dose rate of 1.2mSv/y. A low average dose is recorded over the basalt. The average radiation dose recorded in the study area is 1.08mSv/y, while its range is from 0.001 to 4.41mSv/y. The estimated effective doses within the Al Aziziah area and vicinity area were higher than 1mSv/y, which is the public exposure limit, and lower than the occupational exposure limit of 20mSv/y. We recommend ventilating homes and offices in these places on an ongoing basis and constant radon measuring in closed places.

Circulation of Radon Progeny in the Terrestrial Atmosphere During Thunderstorms

AbstractWe describe a new phenomenon in atmospheric physics—222Rn progeny circulation during thunderstorms. The enhancement of the natural gamma radiation during thunderstorms was measured with precise gamma ray spectrometers. Results of measurements performed at Aragats mountain in Armenia during summer 2020 demonstrate the Rn progeny lifted to the atmosphere by a near‐surface electric field are returned backward to the ground by rain precipitation. Thus, thunderstorms not only return negative charge to the Earth by lightning flashes but also maintain Rn progeny circulation in the atmosphere; it this way, significantly enlarging natural gamma radiation above the Earth surface and Radon concentration in the atmosphere.

Radiological Hazard Assessment of Sharp-Sand from Ilorin-East, Kwara State, Nigeria

Measurement of activity concentration of primordial radionuclides 40K, 232Th, 238U and the corresponding gamma dose rate over a major sharp-sand field in Ilorin, Nigeria, was carried out using Super Spec RS125 gamma ray spectrometer. The RS125 gamma spectrometer gives in-situ measurement of radioactivity concentration. Measurements were taken in 50 locations. The peak values of the measured activity concentrations of 40K, 238U, 232Th, the dose rate (D) and the resulting annual effective dose (AED) are 688.60, 48.17, 30.86 Bqkg−1, 49.50 nGyh−1 and 0.06 mSvy−1 respectively, while their corresponding lowest values are 31.30, 1.24, 0.41 Bqkg−1, 4.70 nGyh−1, and 0.01 mSvy−1 respectively. The estimated mean values of 40K, 232Th, 238U, the gamma dose rate (D) and AED are 454.48, 13.52, 11.63 Bqkg−1, 32.96 nGyh−1 and 0.04 mSvy−1 respectively. Consequently, the mean values of the measured radionuclides and the hazard parameters i.e. dose rate and annual effective dose are within the permissible levels. This follows that the risk of radiation exposure for this location is comparatively less, but the general public may not be safe from exposure to indoor ionizing radiation since no amount of radiation is safe for stochastic effects.