• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.410-414
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• 1998

The dependence of substrate material and electrode position were studied by radiation analysis of Ar discharge, and electron beam radiation was applied to confirm the crosslinked structure of the film. Comparing the conductor substrate with the insulator substrate, the former had lager peak density of radiation spectrum than latter. From the result of peak density of metastable state and ion, it was confirmed that the peak density of ion was falling to the down limit with increasing the distance of electrode by analyzing the radiation spectrum of polymerized films. When the polymerized styrene films was exposed to electron beam, it was possible to form a pattern with the insulator substrate.

• Journal of Radiation Protection and Research
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• v.13 no.2
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• pp.29-40
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• 1988

A spectrum-exposure rate conversion operator G(E) for a portable HPGe detector used for field environmental radiation survey was theoretically developed on the basis of a space distribution function of gamma flux emitted from a disk source and an areal efficiency of the detector. The radiation exposure rates measured using this G(E) and the portable HPGe. detector connected to a portable multichannel analyzer were compared with those measured by a 3' ${\phi}\;{\times}$3' NaI(Tl) scintillation detector with the reported G(E) and a pressurized ionization chamber. A comparison of the three results showed that the result obtained using the HPGe detector was lower than those determined using the NaI(Tl) detector and ionization chamber by 17% to 29%, The difference obtained is close to that reported in literature. The method developed here can be easily applicable to obtain a G(E) factor suitable to any detector for detecting the exposure rate of environmental gamma radiation, since the spectrum-exposure rate conversion operator can be calculated by a hand calculator.

• International Journal of Railway
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• v.7 no.4
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• pp.109-116
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• 2014

For optimization of a low-noise track system, rail vibration and noise radiation needs to be investigated. The main influencing parameters for the noise radiation and the quantitative results of every track system can be obtained using a calculation model of generation and radiation of railway noise. This kind of model includes contact modeling and the calculation model of the dynamic properties of the wheel and the rail. This study used a nonlinear wheel/rail interaction model in the time domain to investigate the excitation of the rolling noise. Wheel/rail response is determined by time integrating Green's function of the rail together with force impulses from the wheel/rail contact. This model and the results of the study can be used for supporting calculation with the conventional model by an addition of the contributions due to nonlinearities to the roughness spectrum.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.77-80
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• 2010

The spectroscopy toolkit has been developed and tested. The toolkit consists of a CsI(Tl)/PIN diode detector, integrated electronics, and a multi.channel.analyzer and its size was 40 cm(width) by 20 cm(length) by 6 cm(high). It is compact, very portable and simpler and cheaper compared to the conventional spectroscopy system. The gamma energy resolutions of the toolkit were 7.9% for the 660 keV of $^{137}Cs$ and 4.9% for 1,332 keV of $^{60}Co$ respectively. The linearity for gamma energies was good. When the energy spectrum of a ceramic sample containing $^{232}Th$ was measured with the spectroscopy toolkit for 20 minutes, there were significant peaks of the heavy metal. These results show that the resolution of the spectroscopy toolkit is sufficient to accumulate a quality spectrum in a few minutes by using weak, encapsulated commercial sources. Furthermore a toolkit experiment that how to measure energy spectra using the toolkit, and how to identify specific isotopes in a pottery piece, could be widely adopted for education and even for more sophisticated and higher level experiments.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.93-99
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• 2016

Background: Industrial X-ray CT system is normally applied to non-destructive testing (NDT) for industrial product made from metal. Furthermore there are some special CT systems, which have an ability to inspect nuclear fuel assemblies or rocket motors, using high power and high energy (more than 6 MeV) pulsed X-ray source. In these case, pulsed X-ray are produced by the electron linear accelerator, and a huge number of photons with a wide energy spectrum are produced within a very short period. Consequently, it is difficult to measure the X-ray energy spectrum for such accelerator-based X-ray sources using simple spectrometry. Due to this difficulty, unexpected images and artifacts which lead to incorrect density information and dimensions of specimens cannot be avoided in CT images. For getting highly precise CT images, it is important to know the precise energy spectrum of emitted X-rays. Materials and Methods: In order to realize it we investigated a new approach utilizing the Bayesian estimation method combined with an attenuation curve measurement using step shaped attenuation material. This method was validated by precise measurement of energy spectrum from a 1 MeV electron accelerator. In this study, to extend the applicable X-ray energy range we tried to measure energy spectra of X-ray sources from 6 and 9 MeV linear accelerators by using the recently developed method. Results and Discussion: In this study, an attenuation curves are measured by using a step-shaped attenuation materials of aluminum and steel individually, and the each X-ray spectrum is reconstructed from the measured attenuation curve by the spectrum type Bayesian estimation method. Conclusion: The obtained result shows good agreement with simulated spectra, and the presently developed technique is adaptable for high energy X-ray source more than 6 MeV.

• Journal of the Korean Society of Radiology
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• v.6 no.6
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• pp.483-487
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• 2012

In 1895, the discovered X-ray is used for not only in this field of medicine wide but also field. The detection of radiation after, people realized the risk of the radiation exposured recommended the principle about the protection of radiation by the part of the effort for lowering the radiation exposure. In this recommendation, all unnecessary radiation exposure have to be prevented by All doses include the protection of radiation, general idea of applicable two kinds of that it has to low maintain. Presently, in the General X-ray room of the clinical, the lead (Pb) was used for the shielding, However, because it had the problem of the lead poisoning which is fatal in the human body, the alternatives was showed. and Among them, the material that it is the tungsten was presented. in this research, the absorbed spectrum according to the thickness in the continuous X-ray energy of the tungsten which is not harmful to the human body through the Monte Carlo simulation, tried to compare with the absorbed spectrum of the lead (Pb). The tungsten confirmed that simulation presumption than result lead in the whole domain that absorbed probability was higher and it is considered that tungsten shows the absorbed efficiency higher than the lead in particularly, 70 keV ~ 90 keV and the tungsten is more useful to the X-ray energy cover of the high energy diagnostic area.

• Journal of the Korean Society of Radiology
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• v.7 no.1
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• pp.51-55
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• 2013

When the X-ray energy is high, the X-ray penetrates the object and decrease the contrast of imaging, and when the X-ray energy is low, the X-ray increases the contrast of imaging but it is to be absorbed into the object, which in the long run increases patient's radiation exposure level. Therefore, appropriate X-ray energy is an essential element affecting the imaging quality and radiation exposure level. This study simulated the energy spectrums according to the target materials of mammography, and compared qualities of phantom imaging for the management of radiolographic quality and patient's radiation exposure level with the introduction of the mammography that employs diversified radiation quality by using new anode materials.

• Journal of Radiation Protection and Research
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• v.49 no.1
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• pp.1-18
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• 2024

Exponential growth has been observed in nuclear medicine procedures worldwide in the past decades. The considerable increase is attributed to the advance of positron emission tomography and single photon emission computed tomography, as well as the introduction of new radiopharmaceuticals. Although nuclear medicine procedures provide undisputable diagnostic and therapeutic benefits to patients, the substantial increase in radiation exposure to nuclear medicine patients raises concerns about potential adverse health effects and calls for the urgent need to monitor exposure levels. In the current article, model-based internal dosimetry methods were reviewed, focusing on Medical Internal Radiation Dose (MIRD) formalism, biokinetic data, human anatomy models (stylized, voxel, and hybrid computational human phantoms), and energy spectrum data of radionuclides. Key results from many articles on nuclear medicine dosimetry and comparisons of dosimetry quantities based on different types of human anatomy models were summarized. Key characteristics of seven model-based dose calculation tools were tabulated and discussed, including dose quantities, computational human phantoms used for dose calculations, decay data for radionuclides, biokinetic data, and user interface. Lastly, future research needs in nuclear medicine dosimetry were discussed. Model-based internal dosimetry methods were reviewed focusing on MIRD formalism, biokinetic data, human anatomy models, and energy spectrum data of radionuclides. Future research should focus on updating biokinetic data, revising energy transfer quantities for alimentary and gastrointestinal tracts, accounting for body size in nuclear medicine dosimetry, and recalculating dose coefficients based on the latest biokinetic and energy transfer data.

• Applied Biological Chemistry
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• v.16 no.1
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• pp.12-17
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• 1973

Alliin was isolated from deep-frozen garlic bulbs and purified into crystalline form. Purity of isolated alliin was assured by melting point determination and thin-layer chromatography. Sulfoxide bond and functional groups of amino acid were confirmed with IR spectrum, and vinyl bond with NMR spectrum. Molecular weight, allyl and other bonds were confirmed with MS spectrum.

• Journal of Radiation Protection and Research
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• v.34 no.4
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• pp.170-175
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• 2009

For the emergency radiation monitoring using gamma spectrometry, we should sufficiently survey the background spectra as environmental samples with systematic nuclide identification method. In this study, we obtained the gamma ray energy spectrum using a HPGe gamma spectrometry system from an air sample. And we identified nuclide of the gamma ray energy peaks in the spectrum using two methods -1) Half life calculation and 2) survey for cascade coincidence summing peaks using nuclear data. As the results, we produced the nuclide identification results for the air sample.