• Journal of Radiation Industry
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• v.11 no.3
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• pp.173-179
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• 2017

The small-scale electroplating device was designed and fabricated for Ni-63 sealed source (foil type) with a high specific activity needed for production of betavoltaic battery. The condition of Ni electroplating was optimized by using fabricated electroplating device to establish a Ni-63 electroplating condition on the Ni foil. The results showed that the optimum surface morphology and thickness of Ni deposit was obtained for 1,758 seconds at a current density of $15mA{\cdot}cm^{-2}$ with 0.5% tween 20. Radioisotope Ni-63 electroplating was implemented under established condition. The radioactivity of Ni-63 sealed source was calculated to $28mCi{\cdot}cm^{-2}$, and the thickness of Ni-63 deposit was about $2.4{\mu}m$.

• Progress in Medical Physics
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• v.10 no.3
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• pp.151-157
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• 1999

The GafChromic film was used for the dosimetry of a balloon angio catheter filled with the radioisotope HO-166 for endovascular irradiation. The balloon angio catheter was 2 cm long and 3 mm in diameter when inflated. The isotope, Ho-166, was produced by the neutron bombardment using the research reactor in Korea Atomic Energy Research Insititute. Co-60 teletherapy beam was used for making H-D curve for the Gaf-Chromic film. The film dosimetry was measured with a videodensitometer. The radial dose distribution indicated that the absorbed dose dropped to about 20% of the surface dose at the 1 mm away from the balloon surface and at 5 mm position the dose decreased to below 1% of the surface dose. The result also shows that with the specific activity of Ho-l66, 250 mCi/ml it takes 230 seconds to deliver 1200 cGy to the region where is 1mm away from the balloon surface. The concentric isodose curves were also presented. The Ho-166 is an another alternative for endovascualr irradiation to prevent restenosis after PTCA (Percutaneous Trans Coronary Angioplasty)

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.889-894
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• 1995

본 연구에서는 ANSI N13.32(1995)에서 제시한 손가락, 손목/발목 기준 팬텀(1)을 설계 제작하여 Teledye사의 말단선량계(finger와 wrist dosimeter)에 대한 방향의존성 실험을 수행하였다. 방사선원으로는 PTB 2차 베타표준선원 $^{204}$Tl(0.24 MeV), $^{90}$ sr/Y(0.8 MeV) 그리고 $^{l37}$ Cs(0.66 MeV) 표준 감마선원을 사용하였으며, 말단선량계로는 LiF Teflon(D-LiF-7-0.13)을 사용하였다. 90$^{\circ}$ 에서 $10^{\circ}$ 까지 20$^{\circ}$ 씩 수직과 수평으로 팬텀을 회전하여 정상각과 비정상각에 대한 상대응답을 제시하였다. 실험결과 90$^{\circ}$에서 모든 선량계는 잘 일치하였다. $^{90}$ Sr/Y은 50$^{\circ}$ 정도에서 다소 방향의존성이 적은 결과를 보였으며, $^{204}$ TI는 20$^{\circ}$에서 최소 13% 정도의 심한 방향의존성이 나타났다. 또한 $^{137}$Cs은 $10^{\circ}$에서도 최대 10.6% 정도의 적은 방향의존성을 나타냈다. 본 실험의 결과로부터 말단선량계는 저에너지와 낮은 투과 방사선[2]에서 심하게 방향의존성이 나타남을 알 수 있었다.

• Journal of Radiation Protection and Research
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• v.22 no.2
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• pp.85-95
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• 1997

TLD and film badges have been traditionally used as formal dosimeters in personal monitoring and are still most widely used. Recently, electronic personal dosimeters based upon Si diode or miniature G-M tube were developed and are getting attractions due to their merits of active nature ; indication of dose rates and the commutative dose, and facilitation of record keeping and radiological control. Response characteristics of the electronic dosimeters including reproducibility, accuracy, linearity, energy and angular dependencies, detection threshold, and response time were examined for three commercial types ; EPD2, STEPHEN6000, and PD-3i. The results were compared with the relevant requirements of IEC standards and Ontario Hydro standards to conclude that their general performances were good. Some specific deficiencies, e.g. incapability of shallow dose measurement of STEPHEN6000, and PD-3i, however, should be corrected to be used as a formal dosimeter.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.12
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• pp.1567-1572
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• 2013

To supply electric power in certain extreme environments such as a spacecraft or in military applications, a radioisotope thermoelectric generator has been highlighted as a useful energy source owing to its high energy density, long lifetime, and high reliability. A radioisotope thermoelectric generator generates electric power by using the heat energy converted from the radioactive energy of a radioisotope. In this study, FE analyses such as radiation shield analysis, heat transfer analysis, and power recovery rate analysis have been carried out to achieve an optimal design for a radioisotope thermoelectric generator using $SrTiO_2$.

• Journal of Radiation Protection and Research
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• v.40 no.3
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• pp.181-186
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• 2015

Measurement of xenon radioisotopes from nuclear fission is a key element for monitoring underground nuclear weapon tests. $^{131m}Xe$, $^{133}Xe$, $^{133}mXe$ and $^{135}Xe$ in the air can be detected via low background systems such as a beta-gamma coincidence counting system. Radioxenon monitoring is performed through air sampling, xenon extraction, measurement and spectrum analysis. The minimum detectable concentration of $^{135}Xe$ can be significantly variable depending on the sampling time, extraction time and data acquisition time due to its short half-life. In order to optimize the acquisition time with respect to certain experimental parameters such as sampling and xenon extraction, theoretical approach and experiment using SAUNA system were performed to determine the time to minimize the minimum detectable concentration, which the results were discussed.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.186-191
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• 2007

The objective of this research was to assess the reliability of data and to improve nuclear analytical techniques concerning the Domestic Radioactivity Intercomparison program for environmental radioactivity monitoring of Jeju from 1998 to 2006. Gross beta for filter papers and water samples was determined, and gamma nuclides for natural and artificial nuclides in soil and water samples were analyzed. The gross beta activity of all samples except for the water samples of 1998 and 1999 showed a good agreement within the confidence intervals. In gamma nuclides, $^{40}K$ and $^{137}Cs$ of soil samples and most nuclides in the water samples, with the exception of several nuclides, were evaluated to be reliable. Based on these results, it is considered that a reliable method for the analysis and monitoring of environmental radioactivity were established, which may play an important role in case of emergency radiation accident.

• Science of Emotion and Sensibility
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• v.27 no.2
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• pp.105-112
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• 2024

Forward head posture (FHP) is a representative postural deformation problem in people today, causing various physical and mental problems, but the effect of FHP on discomfort or distraction during rest is not well known. Accordingly, this study aims to demonstrate the effect of FHP on these brain functions by analyzing brain wave signals at rest. Thirty-three heavy users of computers participated in this study, and all of them exhibited functional FHP when using computers. All participants performed using both normal posture and FHP, and their brain waves were measured at rest while maintaining each posture for five minutes without stimulation. Brain wave signals were acquired using EEG with 32 channels, and through frequency analysis, changes in delta and beta waves, known to be closely related to discomfort and attention, were compared and analyzed depending on the posture. As a result, FHP showed a significant decrease in delta waves in nine channels compared to the normal posture, and a significant increase in beta waves in 14 channels, showing that FHP does affect brain function at rest. These changes are consistent with those that occur under conditions of psychological discomfort and distraction, and they appear to be because the increased discomfort caused by musculoskeletal changes in the FHP also affects brain activity. These can provide important results showing that posture correction can help improve brain function and psychological state at rest.

• Journal of the Korean Society of Radiology
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• v.13 no.6
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• pp.847-856
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• 2019

The various environmental issues arose with the development of today's economy. naturally, people were increased interest in environment and the importance of research on drinking water and contamination are emerging especially. A number of country areas, uranium and ²²²Rn in ground water have been detected to people using as drinking water. So this study evaluated the way for more accurate measurements than when measuring ²²²Rn concentrations in the ground water containing. the experiment was performed using the low-level liquid scintillation counter with an alpha, beta analysis easy PSA function of pulse. the scintillator as the preparation of the ground water samples are mixed, the measure value detection is lowered over prepare period and expiration date. Energy spectrum was also moved to a lower side channel. As a long time to buy the scintillator and over time after opening, it was confirmed that detection is lowered. if the purpose is to use a different scintillator can see the energy through the channel change.

• Journal of Radiation Industry
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• v.8 no.3
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• pp.141-146
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• 2014

Nickel (Ni) electroplating was implemented by using a metal Ni powder in order to establish a $^{63}Ni$ plating condition on the PN junction semiconductor needed for production of beta-voltaic battery. PN junction semiconductors with a Ni seed layer of 500 and $1000{\AA}$ were coated with Ni at current density from 10 to $50mA\;cm^{-2}$. The surface roughness and average grain size of Ni deposits were investigated by XRD and SEM techniques. The roughness of Ni deposit was increased as the current density was increased, and decreased as the thickness of Ni seed layer was increased. The results showed that the optimum surface shape was obtained at a current density of $10mA\;cm^{-2}$ in seed layer with thickness of $500{\AA}$, $20mA\;cm^{-2}$ of $1000{\AA}$. Also, pure Ni deposit was well coated on a PN junction semiconductor without any oxide forms. Using the line width of (111) in XRD peak, the average grain size of the Ni thick firm was measured. The results showed that the average grain size was increased as the thickness of seed layer was increased.