• Progress in Medical Physics
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• v.16 no.2
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• pp.97-103
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• 2005

The energy spectra and dose calculations were performed for secondary neutrons from a 24 MV LINAC using MCNPX code (V2, 4, 0). The energy spectra for neutrons and photons emitted from the LINAC head, and absorbed dose to water were calculated in water phantom. The absorbed doses calculated with Monte Carlo were $0.66\~0.35$ mGy/photon Gy at the surface to d=5 cm, and calculated with interaction data was 0.52 mGy/photon Gy at the depth of electron equilibrium in water. We have shown that this work can be applied to dose estimation of neutrons from high energy LINAC through the comparison of our results with other results.

• Journal of Radiation Protection and Research
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• v.13 no.1
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• pp.1-7
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• 1988

A bubble-damage polymer detector, which operation principles are based on vaporization of superheated liquid drops by interaction with radiations, is developed for neutron dosimetry. The detectors are fabricated by dispersing the superheated liquid drops of Freon12 into transparent and elastic polymer made of acylamide and glycerine. The bubbles formed by neutron irradiation are immediately visible. The neutron sensitivity of the detectors is 4-7 bubbles/10$\mu$ Sv for Am-Be neutrons.

• Nuclear Engineering and Technology
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• v.3 no.3
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• pp.155-160
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• 1971

Average and effective energies for 239Pu-Be, 241Am-Li and 241Am-F neutron sources have been calculated from a number of published data for the neutron spectra and for the dose equivalent as a function of neutron energies by a numerical method. Also a calculation of the dose equivalent conversion factors, i. e., the first collision dose equivalent and the surface (or multicollision) dose equivalent that equals the product of surface-absorbed dose and a corresponding quality factor, per unit fluence of neutrons from these sources has been carried out in the same way as before. The results are as follows : 1. for average energies 4.07$\pm$0.33, 0.42 and 1.41 MeV； 2. for effective energies based on the concept of the first collision process in the human body 4.45$\pm$0.344, 0.51 and 1.47 MeV; 3. for effective energies based on the concept of the multi-collision process in the human body 4.50$\pm$0.36, 0.50 and 1.45 MeV； 4. for fluence-first collision dose equivalent conversion factors (2.74$\pm$0.07)10$^{-8}$ , 1.58$\times$ 10$^{-8}$ and 2.34$\times$10$^{-8}$ rems/(n/$\textrm{cm}^2$); and 5. for fluence-surface dose equivalent conversion factors (3.55$\pm$0.09)10$^{-8}$ , 2.19$\times$10$^{-8}$ and 2.82$\times$10$^{-8}$ rems/(n/$\textrm{cm}^2$) : respectively.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.1
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• pp.23-30
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• 2005

From measured results of the neutron fields at some principal places within the containment building in a CE type nuclear power plant in operation, the radiation exposure of a worker to the neutron at there was evaluated and the equivalent dose reflecting new recommendation (ICRP 60) was compared with that doing the old one (ICRP 26). The measured neutron field was also compared with calibration neutron field. From the analysis, the following conclusion was obtained: the average neutron radiation weighting factor according to new recommendation is 2.41 to 2.71 times higher than the old one. The average neutorn radiation weighting factor at the measured place was similar to that at calibration neutron field. The average neutron energy at measured place was between 42 and 158 keV and higher than that of calibration field of 500 keV. So, the measured equivalent dose in nuclear power plant could be overestimated compared to the real equivalent dose.

• Journal of Radiation Protection and Research
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• v.11 no.1
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• pp.37-43
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• 1986

Dosimetric quantities for 300 keV neutrons in the ICRU standard tissue sphere were evaluated. The Monte Carlo code NEDEP which performs neutron-photon-charged particles coupled transport was used in the direct estimation of absorbed dose and dose equivalent. Some important quantities calculated are as follows; Deep dose equivalent index $H_{I,d}:1.78{\times}10^{11}\;Sv-cm^2$ Shallow dose equivalent index $H_{I,s}:2.08{\times}10^{-11}\;Sv-cm^2$ Ambient dose equivalent $H^*(0.07):1.7{\times}10^{-11}\;Sv-cm^2$ Ambient dose equivalent $H^*(10):1.78{\times}10^{-11}\;Sv-cm^2$ Effective quality factor $\bar{Q}^*(10):12.4$

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.931-936
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• 1995

서울시 중심부 300m 상공에서 약 22kT의 플루토늄 원폭이 폭발했을 때를 가정하고 폭발시 나오는 초기 방사선에 의한 선량을 계산하였다. 계산을 위하여 몬테칼로 코드인 MCNP4A를 이용하였으며 방사선의 위해도를 알아보기 위하여 선량당량으로 환산 하였다. 계산 결과 가까운 거리에서는 평균자유행로가 짧은 중성자에 의한 선량이 높게 나왔으나 거리가 멀어질수록 감마선에 의한 영향이 더 큰 것으로 나타났다.

• Journal of radiological science and technology
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• v.36 no.2
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• pp.165-173
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• 2013

This study was the estimation of the dose distribution for proton, prompt gamma rays and proton induced neutron particles, in case of exposing the proton beam to polymer gel dosimeter and water phantom. The polymer gel dosimeter was compositeness material of Gelatin, Methacrylic acid, Hydroquinone, Tetrakis and Distilled water. The density of gel dosimeter was $1.04g/cm^3$ which was similar to water. The 72, 116 and 140 MeV proton beams were used in the simulation. Proton beam interacted with the nuclei of the phantom and the nuclei in excited states emitted prompt gamma rays and proton induced neutron particles during the process of de-excitation. The proton particles, prompt gamma rays, proton induced neutron particles were detected by polymer gel dosimeter and water phantom, respectively. The gap of the axis for gel was 2 mm. The Bragg-peak for proton particles in gel dosimeter was similar to water phantom. The dose distribution for proton and prompt gamma rays in gel dosimeter and water phantom was approximately identical in case of 72, 116 and 140 MeV for proton beam. However, in case of proton induced neutron particles for 72, 116 and 140 MeV proton beam, particles were not detected in gel dosimeter, while the Water phantom absorbed neutron particles. Considering the resulting data, gel dosimeter which was developed in the normoxic state attentively detected the dose distribution for proton beam exposure except proton induced neutron particles.

• Journal of Radiation Protection and Research
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• v.31 no.2
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• pp.65-68
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• 2006

In this study, the extent of plasmid DNA damage was observed according to concentration of BSH(Boron Sulfhydryl Hydride) and irradiation doses of neutron and ${\gamma}$-ray. The plasmid used was both pBR 322 (2870 bp) and ${\Phi}X174$ RF(5386 bp) DNA. Plasmid DNA damage by irradiation in the presence of BSH was analyzed by agarose gel electrophoresis. In the neutron experiment, DNA damage of both plasmid DNAs was increased according to increasing the concentration of BSH and neutron doses. But in the ${\gamma}$-ray experiment, there appeared no dose dependency as compared to the neutron experiment. The extent of the plasmid DNA damage in the presence of BSH was somewhat different according to irradiation by neutron or ${\gamma}$-ray.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1696_1697
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• 2009

실리콘형 다이오드가 중성자에 노출되면 소자 내부에서 변위손상 발생으로 인한 저항의 변화현상이 발생하며, 이 변화량은 피폭된 중성자의 선량과 비례관계에 있다. 단위 중성자 피폭량에 대한 소자의 저항성 변화량은 감도로 표현되며 감도의 크기는 측정하려는 용도에 적합하게 조절되어야만 활용도를 높일 수 있다. 본 연구에서는 군용 중성자 탐지소자로 활용할 중성자 탐지소자로서 다양한 구조의 핀 다이오드를 제작하고 구조에 따른 중성자 감도를 분석하여 최적의 감도를 가지는 조건을 설정하고 개별소자 형태의 반도체 소자를 제작하였다. 제작된 소자의 중성자탐지능은 측정범위내에서 우수한 선형성을 보였고 온도에 대한 의존성 시험에서 안정적인 특성을 나타내었다.

• 대한방사선치료학회:학술대회논문집
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• 1997.03a
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• pp.13-14
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• 1997