NaI Detector Research Articles

Evaluation of Radon Concentration in Soil Sample from Boreholes in Kaltungo Local Government Area of Gombe State, Nigeria

The evaluation of radon concentration in soil sample from boreholes in Kaltungo local Government area of Gombe state, Nigeria have been carried out. A total of fifteen (15) soil samples were collected from different boreholes sites in five (5) different locations and were analyzed using Gamma spectrometry (Sodium Iodide with thallium NaI (TL) detector. The mean result of Radon activity concentration obtained varies from 0.86± 0.05 to 1.71± 0.03 Bqm-3 and the annual effective dose rate ranged from 0.0039 to 0.0077WLm/y respectively. The result shows variations in the radon concentration with various depths which indicates a relative dependence of radon concentration with depths. Comparing the results with the WHO recommended value of 100 Bqm-3 indicate that the mean values for all the boreholes soil samples were below the world recommended value. Also the mean values for all the boreholes soil samples were below the world average radon concentration of 40Bqm-3 (UNSCEAR). The values of AEDE obtained in various borehole soil samples were less than the ICRP world average. Therefore, the soil samples in each of the borehole may not pose any health threat to the residents.

Efficiency of light collection in the combined detector NaI(Tl)//CsI(Na)

Efficiency of light collection in the combined detector NaI(Tl)//CsI(Na)

Characterization of the neutron flux of a 4.3 Ci Am-Be irradiation site using the cadmium ratio k0 method

In order to utilize the capabilities of the neutron activation analysis (NAA) method, a specialized irradiation unit was installed and operated at Damghan University with a 4.3 Ci Am-Be source. In this study, for the mentioned unit, using the cadmium ratio technique from k0 standardization methods, the neutron flux parameters were determined. Gold (197Au) and Indium (115In) were used as monitors for the irradiations, and their activities were measured with a NaI detector. The obtained values for shape factor of the epithermal neutron spectrum α in paraffin and water moderators are α = 0.0181 ± 0.0050 and α = 0.0182 ± 0.0050, respectively. The thermal to epithermal flux ratio values show that the heating rate for fast neutrons in paraffin and water moderators reached 99.1 % and 98.7 %, respectively. The measured values and their precision indicate that both moderators are suitable for use in the current configuration.

Assessment Of Radionuclides Concentration And Radiological Impact Of Abandoned Tin Mines Soils In Some Communities Of Barkin Ladi, Plateau State, Nigeria

The concentration of natural radionuclides in the soil around the world has become an environmental concern for international and national authorities because of the harmful effect of radiation exposure on human health. The samples of soil used for this study were collected from Foron and Heipang districts of Barkin Ladi Local Government Area of Plateau State. The samples were analyzed using Canberra Model 727/727R Lead Shield Gamma-ray Spectrometer with NaI(Ti) detector. The result shows that 40K ranges from 301.91 ± 0.24 Bq/kg to 124.97 ± 0.31 Bq/kg from the mining spot to 400 m away from the mining spots. 226Ra ranges from 105.43 ± 1.76 Bq/Kg to 43.10 ± 0.62 Bq/Kg from mining spots to 400 m away from the mining spots, and 232Th also ranges from 92.79 ± 0.26 Bq/kg to 26.97 ± 0.39 Bq/kg respectively. The absorbed dose rate in the air (Dr) has a mean value of 82.88 nGh-1. The annual effective dose rate (AEDR) mean value was 0.1mSvy-1, and the radium equivalent (Ra eq) mean value was 180.23 Bq/kg, Hex and Hin have mean values of 0.49 and 0.69 respectively. The calculated excess lifetime cancer risk (ELCR) ranges from 0.0003 to 0.00039 with a mean value of 0.00035 in the soil samples. Therefore, this result suggested that the area under study could be termed radiologically unsafe for people living around or close to the area.
 

STUDY OF POISSON NOISE REDUCTION ON GAMMA CAMERA IMAGE USING SPATIAL DOMAIN FILTER

A gamma camera image is produced by a gamma camera that detects the gamma radiation emitted by the radioactive substance or radiopharmaceutical injected into the body. The gamma camera image sometimes has noise that can interfere with the diagnosis. This image is commonly affected by a Poisson-type random noise. This research proposes using a spatial domain filter to study Poisson noise reduction in gamma camera images. The image sample used is the image of a mouse injected with Lu-177-DOTA Trastuzumab with 100 µCi activity detected using a dual-head gamma camera with NaI(Tl) detectors. The grayscale image is treated with Poisson noise, then improved using a spatial domain filter. The spatial domain filters used include Mean, Median, Wiener, and Spatial Lowpass Filters. The mean filter is the best one that can reduce Poisson noise among the four applied filters. The best filter size for noise reduction is 3 with MSE 5.07, PSNR 41.08 dB, and SSIM 0.99.

Physical, structural and nuclear radiation shielding behavior of Ni–Cu–Zn Fe2O4 ferrite nanoparticles

In this study, Ni–Cu–Zn Fe2O4 ferrite nanoparticles have successfully been synthesized utilizing the Co-precipitation technique. The primary objectives encompassed elucidating phase purity, discerning functional groups, scrutinizing surface morphology, and conducting structural analyses. To accomplish these objectives, a battery of advanced characterization techniques was employed, including power X-ray diffraction, Transmission infrared spectroscopy, UV–Visible spectrophotometer, and Scanning electron microscopy. Furthermore, the investigation was extended to the assessment of the gamma ray shielding properties exhibited by the synthesized Ni–Cu–Zn Fe2O4 nanoparticles, spanning an energy range from 122 keV to 1330 keV. This evaluation was carried out through the utilization of a NaI(Tl) detector coupled with a PC-based multichannel analyzer. The acquired data were meticulously compared with established theoretical value. The results of this study point to a viable route for using this simple, cost-effective, and low-temperature synthesis approach to create nanomaterials suited for gamma ray shielding applications, as well as broader radiation protection. This novel technique has the potential to significantly improve radiation shielding technology. Along with this fast neutron attenuation capability of this prepared ferrite samples have been studied in terms of fast neutron removal cross section.

Comprehensive Study of Natural Radioactivity in Building Materials: A Case Study in Ica, Peru

This study evaluates radon exhalation rates and assesses the potential radiological risks of external exposure to primordial radionuclides in building materials employed in the Ica region of Peru, particularly those with high uranium content. The radon exhalation rates are currently measured using a combination of a closed chamber and an active monitor. We proposed a novel method that effectively ensured a hermetic seal for the closed chamber and guaranteed that the efficient maintenance of secular equilibrium. The obtained results ranged from below the detection limit (BDL) to a maximum of 52.3 mBq · kg−1h−1. Gamma spectrometry was employed to measure the concentrations of radionuclides by utilizing a 3′ × 3′ NaI detector. The analysis of cement samples revealed a strong positive correlation between the activity concentration of radium and the radon exhalation rate. The activity concentrations for radionuclides varied, with values ranging from BDL to 60.6 mBq · kg−1h−1 for 226Ra, BDL to 22.3 mBq · kg−1h−1 for 232Th, and BDL to 1074 mBq · kg−1h−1 for 40K. These findings contribute valuable insight to decision-making processes in the Peruvian construction industry, particularly regarding material safety and radiological risk management.

Radiometric survey of sediments and health risk assessments from the southern coastal area of Delta State, Nigeria

Over the years, the release of potential radiological components around the oil exploration environment has increased with potential health implications.Yet; the mechanism and health associated assessment have remained fuzzy to most experimental scientists. The current study determines the activity concentration of radionuclides in sediments and the corresponding health risk assessments from the hydrocarbon exploration environment of the southern coastal area of Delta State, Nigeria. A Sodium-iodide NaI(Tl) detector, with a well-calibrated multichannel analyzer (MCA) to ensure efficiency and energy was utilized. A total of seventy-five sediment samples (Five sediment samples each per community) were collected from the southern coastal area of Delta State, Nigeria. The mean activity concentrations of 40K, 238U, and 232Th of the sediment samples were 3361.48 ± 194.26 Bqkg−1, 40.11 ± 16.17 Bqkg−1, and 45.73 ± 19.27 Bqkg−1 respectively. The obtained mean values exceeded the world standard limit of 400 Bqkg−1, 35 Bqkg−1, and 30 Bqkg−1 respectively. Also, the computed mean radiological health hazard risk of radium equivalent activity (Raeq), representative level index (Iyr), external hazard index (Hex), internal hazard index (Hin), absorbed gamma dose rate (D), annual effective dose equivalent outdoor and indoor (AEDE) and lifetime cancer risk (ELCR) values are 363.94 ± 32.37 Bkgl−1, 2.9657 Bkgl−1, 0.9839, 1.0919, 175.82 nGyh−1, 2.1556 mSvyr−1, 0.8625 mSvyr−1, and 7.5447 mSvyr−1 respectively. The values were found to be slightly higher than the world standard limit. Therefore, the residents that are using the sediments of the southern coastal area for the construction of buildings as well as dwelling in houses built with such sediments are exposed to these radiological materials. This may pose a radiological health risk concern. The obtained results will serve as radiation and radiological baseline data for sediments of the southern coastal area of Delta State, Nigeria.

Assessment of occupational external radiation exposure of workers in the Southwest of Libya using portable NaI detector

In this study, gamma dose rates generated from the naturally occurring radioactive materials (NORM) were measured in the waste streams of a large scale and sludge onshore petroleum operations. Measurements conducted in this work involved: sludge recovery from separation tanks, sludge forming, NORM storage, scaling in oil tubulars, scaling in gas production and sedimentation in produced water evaporation ponds. Field work was carried out in many places of different terrain of an operation oil exploration and production in Murzuq basin in the Southwest of Libya. The radiation dose rates were measured using portable InSpector-1000. A total of 400 dose rates were acquired. The highest dose rate was 70 μSv/h acquired in sludge stored in barrels. The estimated mean annual equivalent doses in this field were in the range of 0.2–2.8 mSv/y in the first scenario, while in the second scenario the calculated mean annual equivalent doses were in the range of 0.04–0.68 mSv/y. It is assumed that workers may face various exposures in the field where measurements took place, considering the total annual effective dose to be 1.53 mSv/y. The main radioisotopes detected in these samples indicated by the display of the measuring device were 226Ra and 228Ra but detecting both radioisotopes in the same run is not achievable by using the display of the screen.

A deconvolution method for estimating proton range from measured intensity distribution of prompt gamma rays

This study developed a technique for proton range verification based on measuring the intensity distribution of prompt gamma rays (PGs) along the beam path in a target and applying a deconvolution method for retrieving the corresponding distribution of PG emissions. The end-of-range Rret=dγp + Rres can be estimated according to the peak position dγp of the retrieved PG emission and the residual range Rres determined from the cross section of the relevant nuclear reaction. A 30-MeV, 1.5-nA proton beam irradiated polyethylene (PE) and polymethyl methacrylate (PMMA) targets, and spatial intensity distributions were obtained by measuring 4.4- and 6.13-MeV PGs from a depth of 0 mm to 10 mm; to this end, a collimator–detector arrangement comprising a 2-inch NaI(Tl) detector and a 2-mm-wide slit collimator was used. Simulations were conducted to identify the profile of PG emissions in a target and to determine the detector response; subsequently, the performance of the developed deconvolution algorithm was validated, and the limits of this approach were investigated. The data from the 30-MeV proton beam experiment were used, and the ranges Rret were estimated to be 7.85 mm for the PE target and 7.07 mm for the PMMA target; these were considerably close to the range at 80% dose fall-off level R80 achieved using Monte Carlo simulations. Our results demonstrated that a NaI(Tl)-based system with a millimeter-wide collimator can effectively resolve the spatial variation of PG emissions along a proton beam’s path. The proposed deconvolution method exhibited strong potential for verifying proton ranges with a sub-millimeter-level accuracy in a relatively simple and reliable manner.

Chemical durability and shielding study of borosilicate glass systems from solid municipal waste ash for radiation shielding applications

Based on municipal solid waste (MSW) ash as a main raw material, three novel borosilicate glasses with the composition of 70 waste + 20 borax + 10 Na2O + x ZrO2, where x = 0, 0.1 or 0.3 (wt. %),were prepared by the traditional melting-annealing technique. The prepared glasses were analyzed by EDX analysis, revealing the rich compositions of the prepared glasses correlated to the MSW ash used by 70 wt.% in preparing glasses. Some optical, chemical and radiation shielding properties of the prepared glasses were investigated. Either Zr addition or 80 kGy of gamma radiation revealed improvement of the glasses optical transmittance and chemical durability in neutral dis H2O, alkaline 0.1 N NaOH and acidic 0.1 N HCl leaching media for 70 days. Electron spin resonance (ESR) revealed the same spectra before and after irradiation, referring to the prevention of free radical formation by irradiation.The shielding parameters were measured by the experimental gamma spectroscopy (NaI detector) and the theoretical Phy-X/PSD software e.g., linear attenuation coefficients (LAC) and the findings revealed high unanimity among them at photon energies 0.662, 1.173 and 1.333 MeV. Another shielding parameters were also studied e.g., mass attenuation coefficients (MAC), effective atomic number (Zeff), effective electron density (Neff) and effective conductivity (Ceff). Presence of various metal oxides and the host trigonal BO3 and tetrahedral BO4 and SiO4 units, and ZrO2 provide the glasses compactness and effectual stability against ionizing irradiation. The prepared borosilicate glasses have highly strong and compacted structures that can inhibit the passage of radiation photons, because of the variety of many glass network formers, intermediates and modifiers present in the used waste ash. The results indicate the highly economic benefit of the prepared glasses, where the useless MSW ash are used mainly by 70 wt.% to produce effective borosilicate glass systems for promising radiation shielding purposes, especially 0.3 Zr borosilicate glass that has the best radiation shielding properties.

High count rate gamma ray pile-up correction method of NaI(Tl) detector based on deconvolution method

The output pulses of NaI(Tl) detectors have long tails due to the long decay constant of their output circuits, and these pulses easily pile up in high-count-rate environments. In this study, we used digital deconvolution combined with a digital filtering algorithm to restore piled-up pulses as separate, narrow, Gaussian-like pulses. Radioactive isotopes were used to calibrate the amplitudes of the signals processed by the proposed method. The gamma spectra with different methods were obtained to verify the proposed methods. Count rates were tested at various source-detector distances, and Monte Carlo simulation data verified that the error was within 14.60 % for count rates up to 1661 kHz. Compared to a commercial digitizer, for event rates up to 851 kHz, the proposed method increased the count rate by a factor of 53 and increased the energy resolution from 21.44 % to 15.50 %, while the energy resolution without pile-up was the same as that of the digitizer.

Synthesis and characterizations of Ce-doped ZnO thin films for radiation shielding

In this research, different amounts of Ce-doped ZnO thin films were synthesized using the spray pyrolysis method. Structural, morphological and optical properties of these synthesized films were investigated. In XRD analyses, wurtzite (hexagonal) structures were observed in the films. In SEM analysis, there were changes in the surface morphology of the films with doping, and in cross-section measurement, the thickness of the films was measured to be approximately 1.2 μm. In UV–vis spectrometry analysis, it is seen that the effect of Cerium contribution on optical transmittance and band gap positively affects shielding. NaI(Tl) detector and gamma energies of 384, 1173, and 1333 keV have been used to investigate the radiation protection properties of these synthesized films. As a result of these measurements, linear attenuation coefficient (LAC) values have been obtained. Radiation shielding parameters have been calculated with these (LAC) values. The Mass Attenuation Coefficient (MAC), Half Value Layer (HVL), Tenth Value Layer TVL (and) Mean Free Path (MFP) values have been also calculated using this LAC result. According to these results, Ce-doped ZnO films were found to be effective in radiation shielding.

A Novel Method for Real-Time Quantification of Radioligand Binding to Living Tumor Cells In Vitro.

Background: Real-time quantification of radioligand binding to cells under in vivo-like conditions improves evaluation of clinical potential. Materials and Methods: SKOV-3 tumor cells were grown in a monolayer on a thin glass plate placed in a sealable shallow chamber with a continuous flow of 125I-trastuzumab solution. The time-dependent cell binding was measured using a NaI detector, and the binding parameters were derived by computational analysis. Results: The detection efficiency of 125I was 65 cps/kBq for radioligand bound to the cells. Experiments were analyzed to find the values of kon and koff. The resulting kon was 3.2-7.9 × 104 M-1 s-1 and koff was 0.11-4.2 × 10-5 s-1. Conclusions: Radioligands can be rapidly evaluated by binding to living cells for selection and optimization of radioconjugates for diagnostic and therapeutic purposes.

Comparative study between micro- and nano-carbon with epoxy for gamma shielding applications

In the current study, the epoxy material was mixed with 10%, and 30% weight percent carbon material as filler in different thicknesses (1 cm, 1.5 cm, and 2 cm). Transmission electron microscope (TEM) measurements showed the average size of the nano-carbon was 20 nm with a standard deviation of 5 nm. The morphology of samples was examined using scanning electron microscopy (SEM), which showed the flatness of the epoxy surface, and when the content of carbon increases, the connection between the epoxy array and carbon increases. The compression test indicates the effect of nano-size on enhancing the mechanical properties of the studied samples. To survey the shielding properties of the epoxy/carbon composites using gamma-rays emitted from Am-241, Ba-133, Cs-137, Co-60, and Eu-152 sources, which covered a wide range of energies from 0.059 up to 1.408 MeV, the gamma intensity was measured using the NaI (Tl) detector. The linear and mass attenuation coefficients were calculated by obtaining the area under each peak of the energy spectrum observed from Genie 2000 software in the presence and absence of the sample. The experimental results obtained were compared theoretically with XCOM software. The comparison examined the validity of experimental results where the relative division rate ranged between 0.02 and 2%. Also, the measurement of the relative division rate between linear attenuation coefficients of micro- and nano-composites was found to range from 0.9 to 21% The other shielding parameters are calculated at the same range of energy, such as a half-value layer (HVL), mean free path (MFP), tenth-value layer (TVL), effective atomic number (Zeff), and the buildup factors (EBF and EABF). The data revealed a consistent reduction in the particle size of the shielding material across various weight percentages, resulting in enhanced radiation shielding capabilities. The sample that contains 30% nano-carbon has the lowest values of TVL (29.4 cm) and HVL (8.85 cm); moreover, it has the highest value of the linear attenuation coefficient (LAC), which makes it the best in its ability to attenuate radiation.

Novel composite based on silicone rubber and a nano mixture of SnO2, Bi2O3, and CdO for gamma radiation protection

Recently, there has been a surge of interest in the application of radiation-shielding materials. One promising research avenue involves using free-lead metal oxides/polymer composites, which have been studied for their radiation shielding and characterization properties. This study reinforced the dimethylpolysiloxane (silicone rubber) composites with micro- and nano-sized particles of tin oxide, cadmium oxide, and bismuth oxide as additive materials. The composites were tested with 20 and 50 weight fractions, and their attenuation coefficients were measured using a NaI(TI) detector at gamma-ray energies ranging from 59.54 to 1408.01 keV. Also, the thermal and mechanical properties of the composites were observed and compared with those of free silicone rubber. The results showed that the 50% nano metal oxide/SR composites exhibited better thermal stability and attenuation properties than the other composites, also possessing unique attributes such as lightweight composition and exceptional flexibility. Consequently, this composite material holds immense potential for safeguarding vital organs, including the eyes and gonads, during radiological diagnosis or treatment procedures. Its exceptional ability to absorb a significant portion of incident rays makes it an invaluable asset in the field of radiation protection.

Measurement of the neutron capture cross section of 185Re in the keV energy region

ABSTRACT Despite various applications of Rhenium in nuclear science and engineering, there have been limited measurements of the neutron capture cross section of 185Re in the keV energy region, with existing data showing discrepancies. To address this, the study employed the time-of-flight method to measure the neutron capture cross section of 185Re. The prompt γ-rays from the neutron capture reactions were detected using a NaI(Tl) detector. The pulse-height weighting technique was employed to determine the neutron capture yield. The measured cross-section values were determined relative to the neutron capture cross section of 197Au in the energy range from 15 to 90 keV. Additionally, the obtained results were corrected for neutron transport effects and impurities. The results of the measurement provided improved accuracy compared to previous studies, contributing to the nuclear data for the capture cross section of 185Re in the keV energy range.

Absolute emission intensities of the gamma rays from the decay of 224Ra and 212Pb progenies and the half-life of the 212 Pb decay

Absolute gamma-ray emission intensities for 36 characteristic gamma rays from the decay of 224Ra, 212Pb, and their progeny were determined by measuring sources calibrated for activity by means of primary methods based on well-defined high-purity germanium (HPGe) detectors at both NIST and NPL. Results from the two laboratories agree with recent data evaluations, except for gamma rays with low emission intensities. The decay schemes have been re-balanced based on the new results. In addition, the half-life for 212Pb was measured using several HPGe detectors, ionization chambers, and a well-type NaI(Tl) detector.

Development of a radiochemical test procedure for the separation of aerosol-borne allergens

An innovative radiochemical method has been developed to determine the filtration efficiency of HEPA filters for biological nanoparticles. The setup based on EN 1822, for flat sheet media, is up to 40 times more sensitive for a single particle than methods based on particle counting, even for low particle concentrations. To achieve such a high sensitivity the radioactive tracer technique is utilised using a solution of bovine serum albumin (BSA) labelled with radioactive iodine (131I). With the aid of an aerosol generator, this solution is nebulised into nanoparticles of a defined size, which are then passed to the test filter via a compressed air flow. On the raw and clean gas side of the test filter, the 131I is measured with two NaI(Tl) detectors. By balancing the measurement data with each other, the filter efficiency can be determined. Initially, the setup has been validated with current particle counting methods, according to EN 1822, to ensure its functionality. Subsequently, the first experiments with radiolabelled nanoparticles gave promising results, as will be shown below. Further experiments also yielded information about filter clogging and its influence on the filter efficiency.

Age-dependent annual effective dose and radiological health risk from salt and soil collected from Padag, Chaghi, Balochistan, Pakistan

ABSTRACT This study aimed to investigate the annual effective dose for different age groups and health hazards associated with natural radioactivity in salt and soil collected from Padag, Chaghi, Balochistan. All samples were analysed by using high-purity germanium (HPGe) and sodium iodide (NaI) detectors. The average values of concentration of 226Ra, 232Th and 40K in salt samples were found to be 10.49, 9.6 and 169.65 Bq.kg−1, respectively, using HPGe detector, while in case of NaI detector, these values were found to be 10.48, 9.89 and 161.73 Bq.kg−1, respectively. Similarly, the average values of concentration of 226Ra, 232Th and 40K in soil were found to be 24.59, 24.89 and 391.72 Bq.kg−1, respectively, using HPGe detector, while in case of NaI detector, these values were found to be 24.46, 24.71 and 358.31 Bq.kg−1, respectively. Significant correlations were found between the results obtained from HPGe and NaI detectors. The values of total annual effective dose due to ingestion of salt were found to be 2.46 × 10−5, 2.45 × 10−5, 3.55 × 10−5 and 1.13 × 10−5 μSv.y−1 using HPGe detector and 2.43 × 10−5, 2.44 × 10−5, 3.55 × 10−5 and 1.13 × 10−5 μSv.y−1 using NaI detector for the age groups (2–7 years), (7–12 years), (12–17 years) and (≥17 years), respectively. The highest value of annual effective dose was found in the age group 12–17 years and minimum was found in the age group ≥ 17 years. However, all values were found to be below the recommended value of 0.29 mSv. Total average radiological risk due to ingestion of salt for all age groups was found to be lower than the reported value.