• Journal of Magnetics
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• v.20 no.2
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• pp.120-128
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• 2015

Beam-quality of medical linac evaluations vary by diverse factors. Because conventional beam-quality evaluation methods yield fragmentary results, a new beam-evaluation method is suggested, and its feasibility is evaluated. The PDDs (percentage depth doses) of 6 MV (Mega-voltage) and 10 MV photon, R (Range) of a 6 MeV (Mega Electron-voltage) and 9 MeV electron were measured and compared with the conventional evaluation methods, and the improved methods $PDD^{10}{_5}$, $PDD^{20}{_{10}}$, $PDD^{30}{_{20}}$, $PDD^{20}{_5}$, $PDD^{30}{_{10}}$, and $R^{70}{_{50}}$, $R^{50}{_{30}}$, $R^{70}{_{30}}$ as the magnetic field of the bending magnet was changed to +2% to -2%, and the results were compared. The comparison showed that the improved methods exhibit a higher discrimination than the conventional methods in each energy regime. $PDD^{10}{_5}$, $PDD^{30}{_{20}}$, $PDD^{30}{_{10}}$ and $R^{70}{_{50}}$, $R^{50}{_{30}}$ should be applied. These methods exhibit a higher discrimination in each energy regime than conventional beam-quality evaluation methods; therefore, they should be used for beam-quality evaluation according to the magnetic field variation.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.111.2-111.2
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• 2013

고주파 전자가속기는 고출력 RF 시스템으로 구동된다. 이러한 고주파 전자가속기에서 고출력 RF 시스템은 종종 고출력 방전으로 인해 가속관에 손상을 입힐 수 있기 때문에 조심스럽게 RF conditioning을 진행 하여야 한다. 일반적으로 RF conditioning은 아주 긴 시간을 필요로 하고, RF 출력을 서서히 높여가며 진행할 필요성이 있다. 한국원자력연구원에서는 9 MeV와 6 MeV 에너지를 출력하기 위해서는 가속관으로 RF 입력을 약 5.5 MW까지 RF conditioning을 진행하여야 한다. 따라서, 본 연구에서는 Klystron 최대 출력이 약 5.5 MW로 한국원자력연구원에서 개발된 S-band (2,856 MHz) RF 전자가속관에 RF conditioning을 진행 하였다. 가속관의 진공을 약 1.0e-7을 유지하면서 반복률을 10 Hz부터 180 Hz로 증가시켰고, RF 입력 파워는 약 6 MW까지 RF conditioning을 진행 하였다. 그 결과 짧은 시간에 RF commissioning을 진행할 수 있었다.

• The Journal of Korean Society for Radiation Therapy
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• v.5 no.1
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• pp.115-119
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• 1992

The beam characteristics and dosimetric measurements of the 6MV X-ray and 6MeV electron beam from a ML-6M linear accelerator are examined. The Percent Depth Dose(PDD) table and the tissue Maximum Ratio(TMR) table are taken from measurement as a function of the field size and the depth. The calculated TMR table from PDD table is compared with those from measurement. Other beam characteristics such as output factor, beam profile(including flatness, symmetry and penumbra), wedge, and the variation of Dmax are presented. All of these dosimetric measurements sufficiently characterized the beam to permit safe clinical use.

• Journal of the Korean Society of Radiology
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• v.5 no.4
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• pp.217-221
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• 2011

$^{237}Np$ is very important material in the fission products of nuclear reactors. Resonance integral(RI) tests of this material is necessary to check between the experiments and the evaluated data. Such feedback to the evaluated data is very important to correct data and improve of codes. The RI for the $^{237}Np(n,{\gamma})^{238}Np$ reaction were measured by using the 46-MeV electron linear accelerator (linac) at the Research Reactor Institute, Kyoto University (KURRI). The measurement was performed in the energy region from 0.005 eV and 10 keV. RI obtained as 804.7 barns, compared with those of the evaluated data in JENDL-4.0 and Mughabghab.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2906-2910
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• 2011

A fluorescent nucleoside analogue, $^AC$, featuring two non-complementary nucleobases linked through an ethynyl group, was synthesized. The extended ${\pi}$-conjugation imparts $^AC$ with red-shifted absorbance (relative to adenine and cytosine) and pale-blue fluorescence. It spontaneously forms nanoparticles, which exhibit considerably enhanced fluorescence, without the help of any additional stabilizing agent. The DMSO/water ratio was an important factor influencing the construction of the NPs. X-ray crystallography confirmed the structure of $^AC$; dynamic light scattering and scanning electron microscopy confirmed the existence of the nanoparticles.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.1
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• pp.72-80
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• 2017

Gamma-ray has some advantages as a weapon: it has the ability to transmutate matter, high penetrability through materials, and it is very harmful to living things. So it is worth to study the features of gamma-ray weapon in order to utilize it. Such abilities were simulated on the basis of Monte Carlo simulation program GEANT4. For the simulation conceptual design of gamma-ray weapon was conducted. High energy electrons, which were necessary for the high energy gamma-rays, were produced by linear electron accelerator, of which the parameters were derived from the Pohang Light Source(PLS-II). Gamma-rays were get by bremsstrahlung mechanism. The spectra of gamma-rays, that were measured at distances of 500 m, 1000 m, 1500 m and 2000 m, were gained by GEANT4.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.588-592
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• 1992

The electrons, which are accelerated to nearly light speed from LINAC(Linear Accelerator), put into Storage Ring. And this electrons circulate in an ultra high vacuum chamber and their orbit is controlled by the electromagnets such as DIPOLE, QUADRUPOLE, SEXTUPOLE & CORRECTION MAGNET. Among them, the dipole magnet is to bend the electron and to produce Synchrotron Radiation(S.R). This paper describes the key point during manufacturing of this magnet, and introduce the field measurement results of the HEECO's successful prototype.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.148-151
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• 1992

There is a definite requirement to continuously monitor the operating characteristics of radiation therapy machines. It is advisable to monitor the symmetry, flatness, and energy stability of x-ray beams. The semiconductor system was developed using commercially available rectifier diode for th assessment of quality assurance In radiation therapy, which is capable of the above measurements. The beam characteristics of 6MV, 10MV and 21MV photon of Microtron electron accelerator were measured using seven-diodes as detectors and the results were compared with that of using a film results dosimetry with a X-Y plotter. The seven-diode detetor is versatile enough to be used for checking beam profile, flatness, symmetry and energy.

• 전기의세계
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• v.13 no.3
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• pp.63-69
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• 1964

한나라의 과학수준이 rocket기술이나 가속기의 출력 energy로서 운운 되었을 때가 있었는데 그때의 기속기는 원자핵 반응을 인공적으로 실험해 보는데 없어서는 안되는 것이기 때문이었다. 2차대전중 원자폭전의 출현을 보게 한 원자로의 발전은 대전후에는 평화적인 이용면에 따르는 응용 분야가 없는 고 energy의 소립자 연구라든지 isotope생산, 고분자화학 및 의료용등에는 대전중에 발전된 잔자기술의 이용으로 더 큰 가속기의 출현이 필요하였다. 특히 이 Electron Accelerator(이하 Linac라고 함)는 높은 고압과 큰 자석을 쓰지 않는 면에서 손쉽게 우리 신변에서 초고압 X선 이상의 효과로 쓸수있게해 주어서 그 이용면은 매우 다급해졌다. 여기서 우리나라의 입장에서 이러한 것을 살펴볼 때 첫째의 radar기술이 충분히 있으면서 이러한 것을 평화적 생산면에서 아직 활용하지 못하고 있으며 한편에서는 외국으로 부터 강력 동위원소를 도입하여 오고 있는데 Linac를 제작하여 여기서 이용하면 이러한 동위원소의 강도 이상의 것을 우리나라 기술로서 제작할 수 있다. 여기서 그 원리와 제작면에 있어서의 문제점 및 국제적인 이용 현황을 소개해 보겠다.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.249-252
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• 2006

Recently, as it has greatly increased the demand on the serviceability of subway, cable tunnel and underground storage, the stability of tunnel structures has been attracting the concern of engineers and researchers. Thus the aim of the present study is to evaluate acid attack resistance of shotcrete using in tunnel structures. And, in order to understand the deterioration mechanism, test using scanning electron microscopy(SEM) analysis and X-ray diffraction showed that the deterioration mechanism due to acid attack in shotcrete.