• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.860-866
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• 2019

The lead element or its salts are good radiation shielding materials. However, their toxic effects are high. Due to less toxicity of bismuth salts, the radiation shielding properties of the bismuth salts have been investigated and compared to that of lead salts to establish them as a better alternative to radiation shielding material to the lead element or its salts. The transmission geometry was utilized to measure the mass attenuation coefficient (${\mu}/{\rho}$) of different salts containing lead and bismuth using a high-resolution HPGe detector and different energies (between 81 and 1333 keV) emitted from point sources of $^{133}Ba$, $^{57}Co$, $^{22}Na$, $^{54}Mn$, $^{137}Cs$, and $^{60}Co$. The experimental ${\mu}/{\rho}$ results are compared with the theoretical values obtained through WinXCOM program. The theoretical calculations are in good agreement with their experimental ones. The radiation protection efficiencies, mean free paths, effective atomic numbers and electron densities for the present compounds were determined. The bismuth fluoride ($BiF_3$) is found to have maximum radiation protection efficiency among the selected salts. The results showed that present salts are more effective for reducing the intensity of gamma photons at low energy region.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3824-3832
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• 2022

Prompt capture gammas are an important part of the fission reactor gamma field. Because some of the structural materials after neutron capture can emit photons with high energies forming the dominant component of the gamma spectrum in the high energy region, the following study of the high energy capture gamma was carried out. High energy gamma radiation may play a major role in areas of the radiation sciences as reactor dosimetry. The HPGe measurements and calculations of the high-energy aluminum capture gamma were performed at two moderator levels in the VR-1 pool-type reactor. The result comparison for nominal levels was within two sigma uncertainties for the major 7.724 MeV peak. A larger discrepancy of 60% was found for the 7.693 MeV peak. The spectra were also measured using a stilbene detector, and a good agreement between HPGe and stilbene was observed. This confirms the validity of stilbene measurements of gamma flux. Additionally, agreement of the wide peak measurement in 7-9.2 MeV by stilbene detector shows the possibility of using the organic scintillators as an independent power monitor. This fact is valid in these reactor types because power is proportional to the thermal neutron flux, which is also proportional to the production of capture gammas forming the wide peak.

• Journal of radiological science and technology
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• v.46 no.1
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• pp.37-42
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• 2023

Most of research on environmental radioactivity is conducted in areas near nuclear power plants, so basic data about the distribution of environmental radioactivity in soil in other areas are insufficient. Therefore, in this study, divide into four categories by the land development characteristics of Incheon and the purpose of development, and confirm the stability of the Incheon through soil sample collection and gamma-ray analysis based on ⁴⁰K, ¹³⁷Cs and ²²⁶Ra (²¹⁴Pb, ²¹⁴Bi). The spectrum obtained by measuring for 80,000 seconds by using the HPGe detector was analyzed by Genie 2000 program. Soil radioactivity concentrations in urban parks of Incheon area are generally within a safe range compared to the results of the Nuclear safety and security commission. However, as ¹³⁷Cs was detected in one park, which will require continuous monitoring.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.477-484
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• 2024

Experimental investigations on gamma - rays attenuation parameters and dielectric spectroscopic properties were done on a polymeric mixture with chemical composition (100-x) polyethylene + x basalt, where x = 0, 1, 3, 5, 10, and 20 wt%. Using the melting blending technique,six nanocomposite polymeric samples were prepared. The linear attenuation coefficient µ of each prepared set of samples was measured using a gamma-ray spectrometer including High Purity Germanium detector (HPGe) at energies 662.5, 1173.24, and 1332.51 keV. Based on the measured values of (µ) and sample density, the other effective shielding parameters were calculated. The values of µ showed an increase with increasing the dopant ratios from 0.0 up to 20.0 wt%. In addition, the µ values decreased with the photon's energy. The µ values were found 0.0847 up to 0.1175 cm^-1, 0.0571 up to 0.0855 cm^-1, and 0.0543 up to 0.075 cm^-1 at 662.5, 1173.24, and 1332.51 keV. for B0 up to B20, respectively. The ATR spectroscopy was done on the prepared samples, and a good evidence of adding the filler to the pure polyethylene (HDPE) was obtained. Besides, an enhancement in dielectric constant by insertion of basalt NPs also recorded and can be attributed to the large dielectric constant of basalt compared to pure HDPE.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.557-563
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• 2018

Coincidence summing correction effects are known to be greater as the efficiency of the detector increases and as the distance between the source and the detector increases. A point source($^{60}Co$) was used to vary the distance in the direction of the detector's center axis and in the radial direction to obtain the P/T ratio for Coincidence summing correction calibration. In this study, values for coincidence summing corrected calibration of the values in the central and radial directions were applied to the mixed volume source(450 ml CRM source) to compare the overall peak efficiency change according to P/T with Geant4. In addition, the efficiency obtained from the mapping method is applied to the seaweed, a marine sample, and the compatibility of the P/T ratio with the detector and sample very dose together. The efficiency corrected to 1,836 keV was applied to the energy zone affected by the efficiency of 500 keV and the relative error of the measured and corrected values was well matcched by the 3.2 % peak efficiency correction. As with 450 mL CRM source, the larger the volume, the lower the P/T ratio was by ${\pm}5%$. This is due to the increased scattering of gamma-rays emitted as the source becomes farther away from the detector, and this change in P/T has been confirmed to affect the Coincidence summing corrected peak efficiency.

• Analytical Science and Technology
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• v.18 no.1
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• pp.59-65
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• 2005

When the low level radioactivity sample is measured, it is required to have many samples. For increase of the sample volume, a scattering and absorbing probability of the emitted gamma-ray in the sample are to be increased. In order to correct the self-absorption effect, the counting efficiency must be calibrated according to a geometrical condition and sample density. But, it is impossible to determine efficiency for counting sample using standard source with the same geometrical condition and density. In this study, the measuring efficiencies were determined with various counting containers and densities. In order to compare the self-absorption effect with the sample density in the various sample container, the variation of the counting efficiency with the densities was investigated by adding NaI, which has high solubility and density. Also, they were compared with Monte Carlo simulation. The self-absorption effect was found to be significant in the low energy region below 0.5 MeV.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.175-184
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• 2023

Based on the actual shape of the detector and the data provided by the manufacturer, the shape of the detector was implemented through Penelope simulation and applied to the appropriate four-layer thickness based on the efficiency obtained from the measurements. Efficiency calculations to determine the effect of the simulated number of Full Energy Peak Efficiency(FEPE) channels in the detector and the outside contact layer in the crystal on the Full Energy Peak Efficiency were performed for various four-layer thicknesses of 0.3, 0.5, 0.7, 1.0, 1.2, and 1.4 mm using the Penelope Code. When the thickness of the external contact layer was increased by 5 times, the Full Energy Peak Efficiency decreased by about 36% for 59.50 keV, and the Full Energy Peak Efficiency decreased by 10% for 1836. In addition, as it increased by 10 times, the Full Energy Peak Efficiency decreased by about 20% for 59.54 keV, and 7% for 1836.01 keV. The Penelope simulated Full Energy Peak Efficiency channel decreases exponentially with the increase in the four layers. In addition, it was confirmed that the total effect curve was well matched with a relative difference of less than 3.5% in the 0.3-1.4 mm dead layer thickness region. However, it was found that the inhomogeneous dead layer is still a parameter in the Monte Carlo model.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.250-251
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• 2004

하나로(HANARO) 수조고온층 정화 계통은 수조고온층에 유입되는 원자로 수조수의 방사성 이온을 거르는 장치이다. 주기적인 수조고온층 계통의 이온교환수지 교체 및 폐기물 처리 작업은 원자로실에서 행하는 작업 중 방사선 피폭이 큰 작업 중의 하나이다. 지금까지 교환되어 일정기간 붕괴된 수조고온층 이온교환수지의 시료를 채취하고 HPGe MCA를 이용하여 수지에 흡착된 방사성 핵종의 종류 및 농도를 측정하고 이를 토대로 붕괴 추세선을 작성하였다.(중략)

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.198-199
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• 2009

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2006.11a
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• pp.363-364
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• 2006