• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3804-3811
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• 2024

The study focuses on creating new boro-silicate glasses doped with SnO₂ for radiation shielding. It examines how substituting Na₂O with SnO₂ affects their structural, optical, and shielding properties. Density increases from 2.406 to 2.488 g/cm³ with rising SnO₂, measured via the Archimedes Method. The examination for the glassy phase was performed using the XRD diffractometer. UV/Vis spectrophotometer analysis reveals reduced refractive index (2.412-1.976) and increased optical absorption-band gap (direct: 3.648-5.662 eV; indirect: 2.994-5.163 eV) with SnO₂ concentrations of 0-9 mol.%). The effectiveness of the radiation shielding was assessed over the 0.059-1.408 MeV gamma-ray energy interval. The analysis demonstrates that when the concentration of SnO₂ increases, the synthesized glasses' linear attenuation coefficient improves. As the SnO₂ content was raised between 0 and 9 mol%, the linear attenuation coefficient rose between 0.489 and 2.892 cm^-1 (at energy of 0.059 MeV) and between 0.126 and 0.128 cm^-1 (at energy of 1.408 MeV), respectively. As the SnO₂ content was raised between 0 and 9 mol%.

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3558-3565
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• 2024

The linear attenuation coefficients (LAC) of four soils (Black cotton (S1), Sandy (S2), Clay (S3), and Sandy (S4)) samples were measured at photon energies released from radioisotopes Co⁵⁷ (122 keV), Ba¹³³ (356 keV), ²²Na (511 and 1275 keV), Cs¹³⁷ (662 keV), Mn⁵⁴ (840 keV), and Co⁶⁰ (1330 keV) using a gamma spectrometer includes a NaI (Tl) scintillation detector. The experimental measurements were confirmed utilizing the Monte Carlo N-particle transport code. The linear attenuation coefficient values enhanced from 0.256 cm^-1 to 0.296 cm^-1 (at E_γ of 122 keV), from 0.126 cm^-1 to 0.142 cm^-1 (at E_γ of 662 keV), and from 0.0938 cm^-1 to 0.105 cm^-1 (at E_γ of 1275 keV), raising the (Fe + Mn) concentration from 0.912 wt% to 11.214 wt%, as well as raising the soil samples density from 1.62 g/cm³ to 1.79 g/cm³. The study also shows an enhancement in the half value thickness, transmission factor, radiation protection efficiency and lead's equivalent thickness due to the enrichment of Fe + Mn concentrations within the studied soils. The results show that the Black cotton soil exhibits better shielding properties for γ-ray than the other soils.

• Journal of Radiation Protection and Research
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• v.11 no.1
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• pp.70-76
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• 1986

In order to establish the national standards of neutron measurements, a manganese sulphate ($MnSO_4$) bath system was developed under the IAEA technical support. This bath system was made up of a spherical s.s. 316 L bath, of 3.5 mm thick and of 125 cm internal diagmeter, filled with a manganese sulphate solution, a solution circulating system, and a $^5Mn\;{\gamma}-ray$ monitoring system. The solution pumped from the bath was introduced into a Marinelli beaker-type monitor vessel which was equipped with two seperate detectors, $3.8cm{\phi}{\times}3.8cm$ NaI(T1) crystals. The performance of the system were tested using the neutron sources, $^{241}Am-Be\;and\;^{252}Cf$, mounted at the center of the bath. From the decay curve analysis of $^{56}Mn$ activity, neutron emission rate of $^{252}Cf$ by the comparative method was obtained to be $3.71{\times}10^7\;n/s\;per\;50{mu}g$ as of November 15, 1985.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.498-501
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• 1998

It was determined whether photostimulated luminescence (PSL) is applicable to the detection of post-irradiation of foods by measuring PSL photon counts for unirradiated and irradiated pepper powder, dried herbs, fresh shrimp, potato, soybean, dried fig, chestnut, dried squid, and dried cod. The samples were irradiated with $^{60}Co\;{\gamma}-ray$ source and PSL photon counts were measured for them. The photon counts of unirradiated samples were lower than 2,000 for potatoes and less than 1,000 for the others. The photon counts of the irradiated samples except dried figs (0.5 kGy), chestnuts (0.2 kGy), and dried squid (0.5 kGy) were higher than 1,000, and the photon counts increased with dose. Thus, PSL might be applied to the primary detection of irradiated foods.

• Journal of Radiation Protection and Research
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• v.4 no.1
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• pp.21-28
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• 1979

A calculation is presented of air-scattered gamma rays using the modified single-scattering approximation. The air-scattered tissue dose rates are calculated for a general purpose taking into account (a) the buildup and exponential attenuation, (b) the energy spectrum at the position of question and (c) the geometrical scattering volume in three dimensions. These calculations have been further modified to render them applicable to a typical field irradiation facility which is surrounded by a shield wall and in which the source is fitted with a beam collimating device. The results of the calculation include the energy spectra, angular distribution and tissue does rates at source-receiver separation distances of from 35m to 300m. The comparison shows that the present method developed may be generally adequate for the gamma-ray air-scattering problems in field irradiation facilities if energy and angular distribution at the shield are unimportant.

• Journal of Radiation Protection and Research
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• v.47 no.3
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• pp.143-151
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• 2022

Background: After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, biological alterations in the natural biota, including morphological changes of fir trees in forests surrounding the power plant, have been reported. Focusing on the terminal buds involved in the morphological formation of fir trees, this study developed a method for estimating the absorbed radiation dose rate using radionuclide distribution measurements from tree organs. Materials and Methods: A phantom composed of three-dimensional (3D) tree organs was constructed for the three upper whorls of the fir tree. A terminal bud was evaluated using Monte Carlo simulations for the absorbed dose rate of radionuclides in the tree organs of the whorls. Evaluation of the absorbed dose targeted ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs, the main radionuclides subsequent to the FDNPP accident. The dose contribution from each tree organ was calculated separately using dose coefficients (DC), which express the ratio between the average activity concentration of a radionuclide in each tree organ and the dose rate at the terminal bud. Results and Discussion: The dose estimation indicated that the radionuclides in the terminal bud and bud scale contributed to the absorbed dose rate mainly by beta rays, whereas those in 1-year-old trunk/branches and leaves were contributed by gamma rays. However, the dose contribution from radionuclides in the lower trunk/branches and leaves was negligible. Conclusion: The fir tree model provides organ-specific DC values, which are satisfactory for the practical calculation of the absorbed dose rate of radiation from inside the tree. These calculations are based on the measurement of radionuclide concentrations in tree organs on the 1-year-old leader shoots of fir trees. With the addition of direct gamma ray measurements of the absorbed dose rate from the tree environment, the total absorbed dose rate was estimated in the terminal bud of fir trees in contaminated forests.

• Journal of Radiation Protection and Research
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• v.35 no.4
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• pp.167-171
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• 2010

Fixed radiation portal monitors (RPMs) deployed at border, seaport, airport and key traffic checkpoints have played an important role in preventing the illicit trafficking and transport of nuclear and radioactive materials. However, the RPM is usually large and heavy and can't easily be moved to different locations. These reasons motivate us to develop a mobile radiation detection system. The objective of this paper is to report our experience on developing the mobile radiation detection system for search and detection of nuclear and radioactive materials during road transport. Field tests to characterize the developed detection system were performed at various speeds and distances between the radioactive isotope (RI) transporting car and the measurement car. Results of measurements and detection limits of our system are described in this paper. The mobile radiation detection system developed should contribute to defending public's health and safety and the environment against nuclear and radiological terrorism by detecting nuclear or radioactive material hidden illegally in a vehicle.

• Nuclear Engineering and Technology
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• v.45 no.6
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• pp.803-810
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• 2013

The U.S. Department of Energy's Fuel Cycle Technologies R&D program under the Office of Nuclear Energy is working to advance technologies to enhance both the existing and future fuel cycles. One thrust area is in developing enabling technologies for next generation nuclear materials management under the Materials Protection, Accounting and Control Technologies (MPACT) Campaign where advanced instrumentation, analysis and assessment methods, and security approaches are being developed under a framework of Safeguards and Security by Design. An overview of the MPACT campaign's activities and recent accomplishments is presented along with future plans.

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.114-115
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• 2009

See Full Text

• YAKHAK HOEJI
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• v.29 no.5
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• pp.246-252
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• 1985

Ginseng proteins were isolated and partially purified to obtain two fractions, namely GI and GII. Radioprotective effects of these fractions were examined on $\gamma$-ray irradiated ICR mice by observing 30-day survival rates after irradiation. Also investigated were the effects of GI fraction on the recovery of radiation damage. As the results, the GI fraction showed strong protection against radiation indicated by the increment of 30-day survival rates, while the GII fraction did not. The GI fraction enhanced the recovery of body and splenic weights and increased the amount of DNA in liver significantly. It also helped to recover the damage done on erythrocytes by increasing the number to normal in short period, however, it had no effect on the recovery of leukocyte counts.