• Nuclear Engineering and Technology
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• v.56 no.8
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• pp.3268-3275
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• 2024

Isotopes are an important aspect of modern medical and scientific research and cyclotron-based isotope production is of particular interest. Cooling devices are required to manage the heat generated by high-energy particle beams to ensure that they can be delivered securely. However, there is considerable scope for further advancements in the design of cooling systems. Therefore, this study uses simulations to investigate the design of innovative cooling systems. Various designs and materials are considered using a variable four-sector collimator and various particle-beam conditions. Thus, new design principles and material and structural optimization strategies are proposed, which can be used to improve the stability and efficiency of isotope production. The results provide insight into technical challenges and may contribute toward advances in medical diagnostics, radiotherapy, and fundamental scientific research. In particular, they can guide the development of isotopebased technologies in nuclear medicine.

• 전기의세계
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• v.14 no.3
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• pp.18-27
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• 1965

It is well known that the starting characteristics of the cold cathode type discharge tubes are irregular. We have two kinds of stabilization for starting characteristics of discharge tubes. Which are the aging test immediately after producing the tubes and the using characteristics. This paper was devoted primaliry to the empric study of relation between the aging and the manufacturing process. And then to stabilize the starting characteristics of discharge tubes by the irradiations of radio-isotope.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.144.2-144.2
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• 2008

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.3
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• pp.24-31
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• 2006

The energy degrader is the most fragile part of the security of a target, has been newly designed to improve the performance of the gas target. Also, the numerical analysis of the heat movement and mechanical movement during the operation of the target has been accomplished. The heat analysis and structure analysis which are using the cooling water flow and pressure in the energy degrader and the finite element analysis program, has been considered with the heat movement and mechanical movement according to the current capacity of proton beam which determines the production yield of the radioactive isotope. Also the possible use range has been determined and at the same time the most suitable running condition according to the current capacity of proton beam has been suggested.

• The Journal of the Korean dental association
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• v.11 no.4
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• pp.271-276
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• 1973

This study is concerned with the effect on Penetration of varing the length of time among the applications of stains, preparations of medicine and radio-active isotope of siver in 120 carious or non carious human teeth with a vital pulp. The study revealed the following conclusions : 1) The stains and preparations penetrated through the dentinal tube and it's seem to be ceased at zone of secondary dentinal area. 2) The stains and preparations did not penetrated in enamel tissues.

• Journal of The Korean Astronomical Society
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• v.26 no.1
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• pp.65-72
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• 1993

Using the Daeduk Radio Telescope, we have observed $J=1\rightarrow0$ transitions of 1$^{12}CO,\;^{13}CO\;and\;C^{18}O$ toward OMC-l. The column densities of $1\~5\times10^{17}\;cm^{-2}\;and\;1\~3\times10^{16}\;cm^{-2}$ have been derived, for $^{13}CO$ and $C^{18}O$, respectively, in the $11'\times11'$ region centered at Orion - KL. The double isotope ratio $[^{13}CO]/[C^{18}O]$ was found to be larger than the cosmic abundance ratio by factors of $2\~10$ which may result from the chemical fractionation effect.

• Journal of Radiation Protection and Research
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• v.35 no.3
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• pp.117-123
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• 2010

Plutonium is by far the most important of the transuranic elements which have been released into the environment due to radio-toxicity and long term radiation effects on humans. And Pu isotope ratio ($^{240}Pu/^{239}Pu$) is of great interest because this ratio is used as a fingerprint for different sources. Mass spectrometry has been used as an useful atom counting technique with several advantages over decay counting techniques for the determination of Pu isotopes. It enables a determination of Pu isotope ratio in the environmental samples with a low detection limit and a short determination time. An ICP-MS is the representative mass spectrometry for Pu determination. In this study, the precision of $^{240}Pu/^{239}Pu$ isotope ratio was improved by using 4 multiple ion counters of MC-ICP-MS. The detection limit of $^{239}Pu$ and $^{240}Pu$ were $0.10\;fg\;ml^{-1}$ ($0.24\;{\mu}Bq\;ml^{-1}$), $0.12\;fg\;ml^{-1}$ ($0.97\;{\mu}Bq\;ml^{-1}$), respectively. The relative standard deviation of $^{240}Pu/^{239}Pu$ isotope ratio was less than 1 % in trace level. The various reference materials (seawater, soil and sediment) were analyzed to verify this method and their analytical results were in good agreement with the certified (or recommended value) value.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.5
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• pp.282-287
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• 2017

The purpose of this study was predicted the effects of mixing and diffusion due to the operation of the apparatus before the development of the mixed diffusion device for the decontamination absorbent to minimize the influence of contaminant inflow due to radiation accident. The tracer used for the flow characteristics was $^{68}Ga$, $^{99m}Tc$, which is a radioactive isotope, and 2 inch NaI radiation detector was used to detect it. The impeller of the decontamination mixed diffusion system applied to this study was made into three types and the mixing diffusion effect was compared. As a result of analyzing the flow characteristics of the radio-isotope with decontamination mixed diffusion device, mixing, diffusion and flow pattern were obtained. The radial mixing type impeller was able to diffuse to the water surface by the upflow flow, and the fin structure was adjusted for finding optimal conditions. The model 3 type consists of a fin guiding part and an auxiliary fin so that the diffusion speed is higher than that of other types of impellers. It also showed a short time to reach complete mixing.

• The Korean Journal of Quaternary Research
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• v.4 no.1
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• pp.27-40
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• 1990

$^{14}C$ age dating by AMS (accelerator mass spectrometry) technique was performed on twenty five small sized fossil shells and one peat taken from the sixteen piston cores in the southern and southeastern Korean Sea. AMS technique is available to date only a few milligram of amorphous carbons compare than conventional dating technique. It is described in detail of sample pre-treatment and experimental, and applied to the reconstruction of the sea level changes since the late Pleistocene in the Korean Sea. Dated age ranges from 520$\pm$100 to older than 33,500 years. Sedimentary facies in the study area represents a different environmental set which is affected by sea level fluctuation since the late Pleistocene.

• Applied Science and Convergence Technology
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• v.24 no.5
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• pp.178-183
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• 2015

Optical, electrical and structural properties of VOx/ZnO/VOx thin film are studied. The VOx/ZnO/VOx multilayer is deposited by using a radio frequency (RF) sputtering system. The VOx/ZnO/VOx thin film shows the high temperature coefficient of resistance (TCR) of $-3.12%/^{\circ}C$ and the low sheet resistance of about 80 $k{\Omega}/sq$ at room temperature. The responsivity and detectivity of the bolometer are measured as a function of modulation frequency.