• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.516-522
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• 2023

The co-precipitation process plays a key role in the decontamination of radionuclides from low and intermediate levels of liquid waste. For that reason, the removal of Cs ions from waste solution by the co-precipitation method was carried out. A simulated liquid waste (¹³³Cs) was prepared from a 0.1 M CsCl solution, while wastewater generated by washing steel ash served as a representative of radioactive cesium solution (¹³⁷Cs). By co-precipitation, potassium ferrocyanide was applied for the adsorption of Cs ions, while nickel nitrate and iron sulfate were selected for supporting the precipitation. The amount of residual Cs ions in the CsCl solution after precipitation and filtration was determined by ICP-OES, while the radioactivity of ¹³⁷Cs was measured using a gamma-ray spectrometer. After cesium removal, the amount of cesium appearing in both XRD and SEM-EDS was analyzed. The removal efficiency of ¹³³Cs was 60.21% and 51.86% for nickel nitrate and iron sulfate, respectively. For the ash-washing solution, the removal efficiency of ¹³⁷Cs was revealed to be more than 99.91% by both chemical agents. This implied that the co-precipitation process is an excellent strategy for the effective removal of radioactive cesium in waste solution treatment.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2258-2265
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• 2024

The present investigation aims to study the role of Pr₂O₃ on the structural, physical, and radiation shielding properties of a dense cadmium lead borate glass. The XRD was used to affirm the glassy amorphous structure of fabricated sample materials. Moreover, the FTIR was used to record the change in the FT-IR spectra due to the addition of Pr₂O₃ in the wavenumber interval between 400 and 4000 cm^-1. The features of glass surfaces and the elemental analyses for the synthesized Pr₂O₃-reinforced cadmium lead borate glasses were performed using a SEM, supported by an energy-dispersive spectrometer. The γ-ray protection capacity was evaluated using the Monte Carlo method in a wide energy interval ranging between 0.015 and 15 MeV. The linear attenuation coefficient (LAC) at 1 MeV was reduced by a factor of 10 % from 0.372 cm^-1 to 0.340 cm^-1. The decrease in the LAC values negatively affected the other shielding properties such as half-value thickness and the transmission factor. Although the linear attenuation coefficient is decreased slightly with the partial substitution of CdO by Pr₂O₃ compound, the fabricated glass samples still have a high shielding capacity compared to the traditional commercial glasses as well as previous similar reported glasses.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.194-201
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• 2015

We have investigated the EPR signal properties in 12 components of two mobile phones (LCD, OLED) using electron paramagnetic resonance (EPR) spectrometer in this study.EPR measurements were performed at normal atmospheric conditions using Bruker EXEXSYS-II E500 spectrometer with X-band bridge, and samples were irradiated by $^{137}Cs$ gamma-ray source. To identify the presence of radiation-induced signal (RIS), the EPR spectra of each sample were measured unirradiated and irradiated at 50 Gy. Then, dose-response curve and signal intensity variating by time after irradiation were measured. As a result, the signal intensity increased after irradiation in all samples except the USIM plastic and IC chip. Among the samples, cover glass(CG), lens, light guide plate(LGP) and diffusion sheet have shown fine linearity ($R^2$ > 0.99). Especially, the LGP had ideal characteristics for dosimetry because there were no signal in 0 Gy and high rate of increase in RIS. However, this sample showed weakness in fading. Signal intensity of LGP and Diffusion Sheet decreased by 50% within 72 hours after irradiation, while signals of Cover Glass and Lens were stably preserved during the short period of time. In order to apply rapidly EPR dosimetry using mobile phone components in large-scale radiation accidents, further studies on signal differences for same components of the different mobile phone, fading, pretreatment of samples and processing of background signal are needed. However, it will be possible to do dosimetry by dose-additive method or comparative method using unirradiated same product in small-scale accident.

• Journal of the Korean earth science society
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• v.35 no.7
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• pp.554-561
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• 2014

The rock materials from the two stone heritages in the Seonbonsa temple, Gwanbong Seokjoyeoraejwasang (stone Buddha) and three-storied Stone Pagoda, show almost identical petrographic characteristics. They are greyish white porphyritic granites which mainly consist of plagioclase, alkali feldspar, quartz, biotite, hornblende, and chlorite. The rocks from the both heritages are petrographically similar to those from the outcrops of the Palgongsan granite near the temple. Modal compositions exhibit that the rocks from the stone Buddha belong to monzogranite, whereas those from the pagoda and the outcrop near the temple correspond to syeno- to monzo granite. Whole rock magnetic susceptibility data indicate that the rocks from the stone Buddha, the pagoda, and the outcrop have nearly the same susceptibility values ranging 9-16(${\times}10^{-3}\;SI$). Gamma spectrometer data obtained from these rocks also demonstrate the same value range. In conclusion the two stone heritages in the Seonbonsa temple were made of the Palgongsan granite surrounding the temple.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.28-34
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• 2018

Purpose With regard to the use of radioiodine in domestic medical institution, the case of exceeding the allowance of nuclear safety Act about radioactive concentration in drainage was found. Through understanding the cause of exceeding case and analyzing radioactive concentration in drainage, evaluating the relationship of the public waters in surroundings and usefulness. Materials and Methods From November 1, 2014 to April 30th, 2015, the research is aiming at domestic twenty hospitals for six months. By using a HPGe gamma-ray spectrometer(Canberra DSA-1000) and GENIE-2000 Analysis software for comparative analysis, measuring a radioactive concentration of radioiodine in drainage. Consequently, we confirm the excess of radioactive concentration of radioiodine in seven medical institutions. Results Conducting a survey of twenty hospitals and average radioactive concentration of radioiodine in drainage appears $42,100Bq/m^3$. The features of domestic hospitals where show a high radioactive concentration are a number of medical treatment patient when using radioactive iodine and the absence of private rest room. During I-131 whole body scan, the pretreatment procedure of urinating is considered emission of residual Iodine. In public waters, the cause of exceeding detect on radioactive concentration in drainage suppose a diagnostic radioactive iodine. Conclusion We confirm the importance of enhanced education, providing a safety control instructions and installing a private rest rooms for patients who injected a low capacity radioiodine. Also, constructing institutional and legal management system is considered about the Emission management standard in drainage.

• The Journal of the Petrological Society of Korea
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• v.28 no.4
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• pp.227-236
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• 2019

Medium to coarse-grained biotite granodiorite was used to build the Standing Buddha Statue in the Gwanchoksa temple. An ancient document revealed the period and place of constructing the statue: it was made in the northwest of Mt. Banyasan and then moved eastward. Also, the comparison of standing Buddha statue and basement rock in terms of texture, magnetic susceptibility, and gamma spectrometer shows that they have similar characteristics, which is considered to be the same provenance rock. The damage caused by surface contaminants observed in the statue seems to be a combined effect of environmental factors and aging of the epoxy resin. After removal of the contaminants in 2007, the contamination has resumed, and continuous monitoring is necessary. Algal engraftment becomes faster when biological contamination occurs on the surface of stone cultural heritage. Since the secondary lichen growth forms a symbiosis with mold, it is necessary to observe the spatial and distributional changes. Also, the aging epoxy resin may cause secondary damage due to contaminants generated due to the determination of salts, and deterioration of bonding strength due to breaking out. Thus it is desirable to secure stability through proper conservation management.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.167-171
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• 2016

Background: TlBr is of considerable technological importance for radiation detection applications where detecting high-energy photons such as X-rays and ${\gamma}$-rays are of prime importance. However, there were few reports on investigating optical properties of TlBr itself for deeper understandings of this material and for making better radiation detection devices. Thus, in this paper, we report on the optical characterizations of TlBr single crystals. Spectroscopic ellipsometry (SE) and photoluminescence (PL) measurements at RT were performed for this work. Materials and Methods: A 2-inch TlBr single crystalline ingot was grown by using the vertical Bridgman furnace. SE measurements were performed at RT within the photon energy range from 1.1 to 6.5 eV. PL measurements were performed at RT by using a home-made PL system equipped with a 266 nm-laser and a spectrometer. Results and Discussion: Dielectric responses from SE analysis were shown to be slightly different among the different samples possibly due to the different structural/optical properties. Also from the PL measurements, it was observed that the peak intensities of the middle samples were significantly higher than those of the other two samples. With the given values for permittivity of free space (${\varepsilon}_0=8.854{\times}10^{-12}F{\cdot}m^{-1}$), thickness (d = 1 mm), and area ($A=10{\times}10mm^2$) of the TlBr sample, capacitances of TlBr were 6.9 pF (at $h{\nu}=3eV$) and 4.4 pF (at $h{\nu}=6eV$), respectively. Conclusion: SE and PL measurement and analysis were performed to characterize TlBr samples from the optical perspective. It was observed that dielectric responses of different TlBr samples were slightly different due to the different material properties. PL measurements showed that the middle sample exhibited much stronger PL emission peaks due to the better material quality. From the SE analysis, optical, dielectric constants were extracted, and calculated capacitances were in the few pF range.

• Journal of the Korean Society of Radiology
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• v.6 no.5
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• pp.403-408
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• 2012

Prompt gamma ray from the natural Indium sample was measured by using an assembly of BGO($Bi_4Ge_3O_{12}$) scintillation detectors in the neutron energy region from 1 to 300 eV. The assembly was composed of pieces of BGO. The spectrometer was composed geometrically as total energy absorption detector. 46-MeV electron linear accelerator which is located at Research Reactor Institute, Kyoto University used for neutron sources from photonuclear reaction. The measurement of the neutron capture resonances was performed to below neutron energy 1 keV, because of strong X-ray effect from photonuclear reaction in Ta target and short distance from the target to an assembly of detector. The distance of neutron flight path is $12.7{\pm}0.02m$. The large neutron capture resonances were measured from 1 to 400 eV. The energy in the capture resonance was compared with the evaluated values. The large resonances were seen in the present measurement. General agreement can be seen between the present measurement and the previous evaluated data in relevant energy region. In the present study, we measured the continues resonance structure above 1 keV neutron energy region. 91.49 eV new neutron capture resonance was found in present measurement.

• The Journal of the Petrological Society of Korea
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• v.19 no.4
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• pp.283-292
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• 2010

The Suljeongri east three-story stone pagoda in Changnyeong (National Treasure No. 34) has been damaged mainly by lots of cracks. The stones used for this pagoda are medium-granied equigranular pinkish biotite granite. Measured magnetic susceptibility values are of from 2 to 9 (${\times}10^{-3}$ SI unit). From the ${\gamma}$-ray spectrometer mesurement K, eU, and eTh contents of the stones are 3 to 7%, 8 to 19 ppm, and 11 to 35 ppm, respectively. Comparing the petrographical and chemical characteristics between the stones of the pagoda and the country rocks near Suljeongri, it is suggested that the most similar rock could be equigranular biotite granite in the western slope of the Mt. Hwawangsan. Vertical, horizontal and diagonal cracks are intensely developed at the lower part of the stone pagoda. Biotite granite has intrinsic microcracks defined as rift and grain rock cleavages. Both rock cleavages are assumed to have led to the crack growth and consequent mechanical damage of the pagoda. It seems that vertical cracks have been grown parallel to the principal compressional stress, and that horizontal cracks to the reacting tensional stress. Diagonal cracks seems likely to have been resulted from conjugate rift and grain rock cleavages.

• Journal of the Korean Society of Radiology
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• v.12 no.2
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• pp.123-131
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• 2018

This study compared PENELOPE with measured values from low energy peak to high energy peak to reduce peak to compton ratio and continuum background spectrum using $^{60}Co$, $^{137}Cs$ and mixed volume source. In addition, the change in backscattering and compton edge efficiency was compared with that of PENELOPE through changes in the vicinity of low energy. The results from the mixed volume source are applied to the soil samples to determine how much the minimum detection limits of the soil samples are reduced in the suppression and unsuppressed mode. The compton suppression of the low energy region of $^{60}CO$ (1,173 keV) was considerable, and the Compton edge RF for the $^{137}Cs$ (661 keV) peak was 2.8. In particular, the $^{60}Co$ source emits coincidence gamma rays of 1,173.2 keV and 1,332.5 keV, so compton inhibition was reduced by approximately 21%. RF of compton edges of 1,173 keV and 1,332 keV emitted from a $^{60}Co$ source was 3.2 and 3.4, and the peak to compton edge ratio was improved to 8: 1. And Compared with Penelope, the uncertainty was well within 2%. In compton unsuppressed mode, MDA values of 661 keV, 1,173 keV and 1,332 keV were 0.535, 0.173 and 0.136 Bq/kg, respectively, but decreased in compton suppressed mode to 0.121, 0.00826 and 0.00728 Bq/kg. Thus, Compton suppressed could reduce the background radioactivity and the radioactivity contained in the detector itself.