• Journal of Radiation Protection and Research
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• v.16 no.1
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• pp.25-32
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• 1991

MCNP code was used to calculate conversion factor H(d)ma at the depths of 0.07 and 10mm within a water phantom recommended by IAEA and within a PMMA phantom required by the US dosimeter proficiency testing programmes. The calculations were performed for an expanded parrallel beam of monoenergetic photons of perpendicular incidence on one faces of the phantom. The results can be used as conversion factor in calibrating individual dosemeters in terms of the dose equivalent quantities defined directly in the phantom.

• Journal of Radiation Protection and Research
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• v.21 no.4
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• pp.297-311
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• 1996

ANSI decided PMMA slab phantom as a calibration phantom and introduced a conversion coefficient calculation method for it. For photon, the conversion coefficient can be obtained by using backscatter factor and conversion coefficient of the ICRU tissue cube and backscatter factor of the PMMA slab. For neutron, however, the ANSI has not introduced any conversion coefficient calculation method for the PMMA slab. In this work, the ANSI method for the photon conversion coefficient calculation was applied to the neutron conversion coefficient calculation of the PMMA slab. Quality weighted tissue kerma of neutron was applied to calculate the backscatter factors on the ICRU cube and the PMMA slab. The dose conversion coefficient of the ICRU cube was also calculated by using MCNP code. Then, the dose conversion coefficient of the PMMA slab was calculated from two backscatter factors and the dose conversion coefficient of the ICRU cube. The discrepancies of the dose conversion coefficients of the PMMA slab and the ICRU cube were less than 10% except 1eV(20%), 1keV(17%), and 4 MeV(16%).

• Journal of Radiation Protection and Research
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• v.20 no.2
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• pp.129-136
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• 1995

In spite of the prescriptions on the reference X-ray fields given by the International Organization of Strandard(ISO) and American National Standard Institute(ANSI), the measurement of X-ray spectrum is not only time consuming but very difficult, paticularly when significant corrections have to be applied to the measured pulse-height distributions of the observed spectra. This paper describes the calculation method of ISO Narrow Series and ANSI X-ray filtered radiations by theoretical model which is modified framer's theory by target attenuation and backscatter correction. The X-ray spectra, average energies and conversion coefficients are calculated and compared with those obtained using the spectra prescribed by ISO and AMSI to assure good agreement.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.57-62
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• 1996

ANSI N13.32는 손목팬텀과 손가락팬텀에서 말단선량계의 특성조사를 위하여 방향의존성인자를 선량계의 성능평가에 적용하도록 권고하고 있다. 본 연구에서는 말단선량의 정확한 선량평가를 위하여 ANSI N13.32에 제안된 팬텀과 동일하게 모사하고 그 팬텀내의 7mg/$\textrm{cm}^2$ 깊이에서 단일에너지를 가진 광자의 선량당량환산인자 및 방향의존성인자를 MCNP 전산코드를 사용함으로써 계산하였다. 또한 본 연구의 최종목적인 ISO Narrow X-선 빔에 의해 조사된 손가락팬텀에서 선량당량환산인자 및 방향의존성인자를 도출하였다. 전산 수행한 결과 낮은 전압에서 발생된 X-선 빔인 경우, 팬텀의 주축을 따라 수평회전각이 증가할수록 방향의존성인자가 크게 감소하며, 한편 높은 전압에서 생성된 X-선 빔인 경우, 수평회전각이 증가할수록 방향의존성인자간 처음에는 근소하게 감소하지만 90。까지는 증가하고 있음을 알 수 있었다.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.883-888
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• 1995

본 연구에서 말단선량계에 대한 선량평가시 선량환산인자를 산출하기 위해 1995년의 ANSI N13.32 기준인 “말단선량계의 성능평가를 위한 기준”에서 제안된 기준 팬덤을 가지고 MCNP 전산코드를 이용하여 커마근사법에 의해 수행하였다. ANSI N13.32의 기준팬텀은 손·발 그리고 손가락을 대표하는 원통형으로서 특히 손·발 팬텀에 대해서는 뼈등가물질로 알루미늄을 삽입한 것을 제안함에 따라 본 계산 목적을 위하여 팬텀설계를 똑같이 모사하였으며 사용된 광자빔 에너지는 20keV에서부터 1.5MeV에 걸쳐 14개의 단일에너지를 선택하여 수행하였다. 본 연구에서 전산수행한 결과를 ANSI N13.32의 실험적 결과와 비교해 볼 때 50keV에서부터 1.5 MeV까지의 에너지 영역에서는 최대오차 6% 이내에서 거의 일치함을 보였다.

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.284-285
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• 2009

• Analytical Science and Technology
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• v.20 no.6
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• pp.460-467
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• 2007

Dose rate conversion factor was calculated to estimate the absorbed effective annual doses for soils for the beta-rays and gamma-rays, which were emitted from $^{238,235}U$, $^{232}Th$, and $^{40}K$ isotopes. The most recent data of the emitted energies per decay, half-lifes, and branching ratios, which were obtained from National Nuclear Data Center, were used. When this factor and the effective annual doses for the beta-rays and the gamma-rays of natural radioisotopes were compared with those of Aitken, these of $^{238}U$, $^{232}Th$ and $^{40}K$ are estimated to have good agreements but a large difference is shown in this for $^{235}U$. Through the calculations of effective annual doses by using these factor and the measurements of gamma-ray spectra for soils, which were extracted from prehistoric remains (Mansuri) on Osong, Chungchengbuk-do, The annual effective doses were obtained to be 3.8~5.9 mGy/yr. Also, when these doses including decay elements upper Rn were compared with those on all isotopes, the differences within 9~30 % were obtained. The analysis method of the annual effective doses for the beta-rays and the gamma-rays of the natural isotopes of soils was established by this dose rate conversion factor.

• Journal of Radiation Protection and Research
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• v.21 no.1
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• pp.41-50
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• 1996

In this study, the theoretical calculation of the air kerma-to-dose equivalent conversion factors was performed with a Monte Carlo N-Particle transport code for the two types of extremity phantom of the ANSI and the KAERI, respectively. Considering the distribution of absorbed dose due to the interaction of homogeneous Parallel broad beam of monoenergetic primary photons in the range between 15keV and 1.5MeV, the air kerma-to-dose equivalent conversion factors based on the kerma approximation were calculated. It is showed that all the theoretical conversion factors of the two types of the extremity phantom for the ANSI and the KAERI agree well with the experimental values of the ANSI N13.32 draft(1995) for each energy within 5.7%, maximum difference ratio, except for 13.6%, difference ratio in the case for the energy of less than 40keV. It is due to uncertainties of experiment occurred in the low X-ray energy range and geometry considered in the MCNP code.

• Nuclear Engineering and Technology
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• v.12 no.3
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• pp.171-179
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• 1980

This paper presentss flux-to-dose conversion factors for neutrons and gamma-rays based on the concept of the maximum absorbed dose. Neutron flux-to-does-rate conversion factors for energies from 2.5$\times$10$^{-8}$ to 20 MeV are presented while the conversion factors for gamma-rays are given in the energy range of 0.01 to 15MeV. Flux-to-does-rate conversion factors, which were calculated under the assumption that the radiation energy distribution has nonlinearity in phantom, are different from those values obtained by monoenergetic radiation. Especially, these values obtained here were determined for the cross section libray such as DLC-23, DLC-27, and DLC-31. The flux-to-dose-rate conversion factors obtained in this work are in a good agreement with the values presented by American National Standard Institute (ANSI) N666. These results are used to calculate the dose rate distribution of neutron and gamma-ray in any radiation fields, and will be useful for the radiation shielding analysis, radiation protection and radiation dosimetry concerned with problems of continuous energy distribution.

• Journal of Radiation Protection and Research
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• v.29 no.2
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• pp.97-104
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• 2004

MIRD-type Korean adult male phantom, 'KMIRD' was constructed to calculate Korean-specific dosimetric quantities for radiation protection consideration. The external shape of KMIRD was based on national physical standard data of Korean. KMIRD has thicket trunk than MIRD5 and arm models divided from trunk. The height and weight of the KMIRD are 171 cm and 63.8 kg. ICRP23 data were referred to constitute organs and tissues of KMIRD. However nine organs were constructed based on Korean reference data provided by Radiation Health Research Institute. In the present study, the MCNPX2.3 Monte Carlo transport code was combined with KMIRD to calculate dose conversion coefficients for photon in the energy range from 0.05 to 10 MeV. The simulated irradiation geometries are broad parallel photon beams in AP, PA, LLAT and RLAT direction. Absorbed dose conversion coefficients were compared with data calculated with MIRD5, MIRD-type phantom based on ICRP23 reference man. In some organs, the discrepancies between two phantoms amount up to nearly 30%. The effective doses conversion coefficients of KMIRD are lower than those of MIRD5. The dose discrepancies between two MIRD-type phantoms ate because of physical differences between Korean and Western, also geometric differences between two phantoms. KMIRD should be revised using the full set of Korean reference data of all organs. The developed MIRD-type Korean adult male phantom can be applied to dose assessment of internal exposure.