• 한국환경성돌연변이발암원학회지
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• 제7권2호
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• pp.103-111
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• 1987

The effects of LET (linear energy transfer) of radiation on the induction of somatic chromosome mutations or gene mutations of Drosophila melanogaster were studied. For detecting somatic chromosome mutations and gene mutations, Drosophila wing spot system and eye-color spot system were used, respectively. The frequencies of somatic chromosome mutations or gene mutations induced after third instar larval treatment with 23 MeV neutrons, thermal neutrons, X-rays were examined. From these data, the RBE(relative biological effectiveness) values of 23 MeV neutrons relative to X-rays for induction of somatic chromosome mutations or gene mutations were calculated. The present results suggest that high LET radiations are efficient than X-ray in producing not only somatic chromosome mutations but also gene mutations.

• Radiation Oncology Journal
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• 제7권1호
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• pp.133-140
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• 1989

Three-dimension paraffin compensator was designed to construct the tissue equivalent compensator for irregular body contours and obiliques beam incidence. The ratio of compensator thickness to tissue deficit was depended on field size, depth and air gap because the scattered dose loss. The ratio of compensator-tissue was optimized 0.79, 0.73, 0.61 and 0.56 in 6MV x-rays as function of field size $4{\times}4$, $10{\times}10$, $20{\times}20$ and $30{\times}30cm^2$ respectively. in our study. Using this tissue equivalent compensator, it can be got 2% difference of dose at same mid-plane in phantom study.

• Journal of Ceramic Processing Research
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• 제20권4호
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• pp.363-371
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• 2019

In this study, physical properties of normal concrete, magnetite concrete, EAF concrete, and EAF concrete with added iron powder were evaluated and a feasibility of radiation shielding is also evaluated through irradiation tests against X-rays and gamma-rays. While the unit weight of EAF concrete (3.21 t/㎥) appeared lower than that of magnetite concrete (3.50 t/㎥), the results in compressive strength of EAF concrete were greater than those in magnetite and normal concrete. While the radiation transmission rate of normal concrete reaches 26.0% in the X-ray irradiation test, only 6.0% and 9.0% of transmission rate were observed in magnetite concrete and linear relationship with unit volume weight and radiation shielding. In the gamma-ray irradiation test, the performance of EAF and magnetite concretes appeared to be similar. Through the results on the excellent physical properties and radiation shielding performance a potential applicability of EAF concrete to radiation shielding was verified.

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1671-1676
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• 2023

The influence of adding iodine as a contrast substance to elevate radiation in a tumor is studied using simulation techniques of Monte-Carlo. The study is carried on a brain cancer by adopting an unsophisticated head phantom. The ionizing radiation source is an external beam of x-rays with energy range of a few tens of keV. The expected radiation dose increment due to adding the iodine is investigated by comparing the radiation in the tumor after and before adding the iodine and calculating the ratio between the two doses. Several concentrations of the contrast substance are used to quantify its impact. The change of the dose increment with the source energy is also examined. It is found that the radiation elevation in the tumor tends to saturate with increasing the iodine concentration, and for the studied domain of energies (30 keV-100 keV), the radiation dose enhancement factors (RDEF) for the different iodine concentrations (1%-9%) show peaked curves, with the peak occurring between 60 keV and 70 keV. For the highest concentration studied, 9%, the peak value is almost 7.

• 한국광학회:학술대회논문집
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• 한국광학회 1991년도 제6회 파동 및 레이저 학술발표회 Prodeedings of 6th Conference on Waves and Lasers
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• pp.64-64
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• 1991

The interaction of high-intensity, focused, nanosecond laser light with matter results in the production of high-temperature plasma, which in turn emits an intense pulse of x rays. The x-ray spectrum consists of strong line components of several keV photon energy and broad continuum. Such an x-ray source provides many advantages over conventional ones for many applications. Pulse nature of the x-ray emission is well-suited for studying transient phenomena and for imaging living biological specimen. Recent experiments have also shown that the laser plasma x ray may be used for x ray lithography. These studies and other applications will be discussed in detail.

• 대한방사선기술학회지:방사선기술과학
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• 제32권2호
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• pp.205-212
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• 2009

반응보정인자(h)는 고체팬텀에서 전리함의 반응을 물에서의 값으로 변환하기 위한 인자이다. RW3 고체 팬텀의 경우에 고에너지 X-선에 대한 반응보정인자는 선질과 깊이에 의존하는 것으로 알려져 있으나 조사면 크기와 SSD(Source to surface distance), 그리고 전리함 종류에 따른 의존성은 알려진 바가 없다. 본 연구에서는 알려진 의존성을 고찰하고 알려지지 않은 인자들에 대한 의존성을 조사하였다. 본 측정에서는 파머형전리함(FC65G, IBA, Germany)과 소형전리함(CC13, IBA, Germany)이 사용되었으며 대상 선질은 6 MV와 15 MV X-선이었다. 측정 결과 반응보정인자는 6 MV의 경우에 깊이 5 cm와 10 cm에서 각각 h = 1.015, 1.021, 그리고 15 MV의 경우에 깊이 5와 10 cm에서 각각 h = 1.024, 1.029로 나타났다. 결론적으로 반응보정인자는 선질과 깊이에는 의존하였지만 조사면 크기와 SSD에 따른 변화는 적었다. 전리함에 있어서 대상의 두 전리함에 대해서는 차이가 없었으나 다른 종류의 전리함에 대해서 추가적 연구가 필요하다고 생각한다. 본 결과는 RW3에서 전리함을 이용한 측정시 측정값의 분석에 활용될 수 있다.

• 한국세라믹학회지
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• 제34권1호
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• pp.109-113
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• 1997

흡수계수가 매우 낮은 비정질 재료의 구조 해석을 하기 위하여 표준 X선 회절 기법을 이용했을 때, 시료의 측정된 X선 회절 강도에는 다중 산란에 의해 발생하는 X선 강도가 상당히 포함된다. 비정질 SiO2와 B2O3에서 사용되는 빔의 종류에 따라 발생하는 다중 산란 빔의 강도를 산출해 주는 컴퓨터 프로그램을 작성하였다. 여러 종류의 X선 빔과 시료 SiO2와 B2O3의 조합을 작성된 컴퓨터 프로그램을 도입하였을 때, 2$\theta$=0~180$^{\circ}$의 범위에서 시료 SiO2의 단일 산란 빔에 대한 다중 산란 빔의 강도 비는 CuK$\alpha$빔; 0.10~0.16%, MoK$\alpha$빔; 0.98~5.87%, AgK$\alpha$빔; 1.88~17.86%로 계산되어졌고, 시료 B2O3에 대한 단일 산란 빔에 대한 다중 산란 빔의 강도 비는 CuK$\alpha$빔; 0.27~0.54%, MoK$\alpha$빔; 2.30~19.69%, AgK$\alpha$빔; 3.96~53.83%로 계산되어졌다. 따라서, X선 회절 기법을 이용하여 비정질 SiO2와 B2O3의 구조 해석에 있어서는, MoK$\alpha$빔 및 AgK$\alpha$빔에서 측정된 X선 회절 강도는 다중 산란 효과에 대해서 반드시 교정하여야 한다.

• Journal of Radiation Protection and Research
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• 제43권3호
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• pp.97-106
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• 2018

Background: A cargo container scanner using a high-energy X-ray generates a fan beam X-ray to acquire a transmitted image. Because the generated X-rays by LINAC may affect the image quality and radiation protection of the system, it is necessary to acquire accurate information about the generated X-ray beam distribution. In this paper, a diode-based multi-channel spatial dose measuring device for measuring the X-ray dose distribution developed for measuring the high energy X-ray beam distribution of the container scanner is described. Materials and Methods: The developed high-energy X-ray spatial dose distribution measuring device can measure the spatial distribution of X-rays using 128 diode-based X-ray sensors. And precise measurement of the beam distribution is possible through automatic positioning in the vertical and horizontal directions. The response characteristics of the measurement system were evaluated by comparing the signal gain difference of each pixel, response linearity according to X-ray incident dose change, evaluation of resolution, and measurement of two-dimensional spatial beam distribution. Results and Discussion: As a result, it was found that the difference between the maximum value and the minimum value of the response signal according to the incident position showed a difference of about 10%, and the response signal was linearly increased. And it has been confirmed that high-resolution and two-dimensional measurements are possible. Conclusion: The developed X-ray spatial dose measuring device was evaluated as suitable for dose measurement of high energy X-ray through confirmation of linearity of response signal, spatial uniformity, high resolution measuring ability and ability to measure spatial dose. We will perform precise measurement of the X-ray beamline in the container scanning system using the X-ray spatial dose distribution measuring device developed through this research.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.3.1-3.1
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• 2007

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.228-232
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• 2003

Mircolens and microlens arrays are realized using a novel fabrication technology based on the exposure of a resist, usually PMMA, to deep X-rays and subsequent thermal treatment. Hot embossing process is also studied for mass production. The fabrication technology is very simple and produces microlenses and microlens arrays with good surface roughness of several nm. The molecular weight and glass transition temperature of PMMA is reduced when it is irradiated with deep X-rays. The microlenses were produced through the effects of volume change, surface tension. and reflow during thermal treatment of irradiated PMMA. A hot embossing machine is designed and manufactured with a servo motor transfer system. The hot embossing process follows the steps of heating mold to the desired temperature, embossing a mold insert on substrate. cooling mold to the de-embossing temperature. and de-embossing. Microlenses were produced with diameters ranging from 30 to 1500 ${\mu}{\textrm}{m}$. The surface X-ray mask is also fabricated to realize microlens arrays on PMMA sheet with a large area.