• 대한전기학회:학술대회논문집
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• 대한전기학회 1983년도 하계학술회의강연.논문초록집
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• pp.118-119
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• 1983

• 한국고분자학회지:고분자과학과기술
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• 제8권3호
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• pp.353-359
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• 1997

• 한국진공학회:학술대회논문집
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• 한국진공학회 1998년도 제14회 학술발표회 논문개요집
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• pp.101-102
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• 1998

• Journal of Radiation Protection and Research
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• 제34권1호
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• pp.25-30
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• 2009

Micro-columnar CsI(Tl) is the most popular scintillator material which is used for many indirect digital X-ray imaging detectors. The light scattering at the surface of micro-columnar CsI(Tl) scintillator was studied to find the correlation between the surface roughness and the resultant image resolution of indirect X-ray imaging detectors. Using a commercially available optical simulation program, Light Tools, MTF (Modulation Transfer Function) curves of the CsI(Tl) film thermally evaporated on glass substrate with different thickness were calculated and compared with the experimental estimation of MTF values by the edge X-ray image method and CCD camera. It was found that the standard deviation value of Gaussian scattering model which is determined by the surface roughness of micro-columns could certainly change the MTF value of image sensors. This model and calculation methodology will be beneficial to estimate the overall performance of indirect X-ray imaging system with CsI(Tl) scintillator film for optimum design depending on its application.

• Journal of Radiation Protection and Research
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• 제43권2호
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• pp.75-84
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• 2018

Background: Gamma-ray spectrometry helps in radiation shielding problems and different applications of radioisotopes. Experimental arrangements including broad beam geometries are widely used. The aim is to investigate and evaluate the ${\gamma}-ray$ spectra via attenuation by environmental materials. Materials and Methods: The photo peak to nominated parts in the ${\gamma}-ray$ spectra and the attenuation coefficients ${\mu}_b/{\rho}$ from broad beam geometries are measured for the materials water, soil, sand and cement at the energies 0.662, 1.25, and 1.332 MeV with a $3{^{\prime}^{\prime}}{\times}3{^{\prime}^{\prime}}$ NaI(Tl) detector. Results and Discussion: The ${\gamma}-ray$ spectra vary according to changes in the effective atomic number $Z_{eff}$ of the attenuator, the photon energy and the solid angle. The peak to total ratios are the most sensitive parts to variations in the experimental conditions and overturn in the region 0.663 MeV to 1.332 MeV. This is indicated as inversion trend. The results are discussed in view of $Z_{eff}$ and the experimental conditions. The intensity build-up is larger at the lower energy and larger scattering angles in agreement with Klein-Nishina formula and other results. The build-up factor B is$${\sim_=}$$1 at high ${\gamma}-energies$ and small scattering angles. Conclusion: The sensitivity to material characteristics decrease gradually from peak: to total, to Compton valley, to Compton plateau ratios. Rigorous collimation is necessary at small energies. Cement, of the largest $Z_{eff}$, is characterized by the maximum broad beam mass attenuation coefficients ${\mu}_b/{\rho}$. The obtained results provide information to decide for the suitable experimental set-up based on aim of the work.

• 한국산업보건학회지
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• 제25권1호
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• pp.82-88
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• 2015

Objectives: This study is designed to analyze the penetration performance into ceiling materials containing asbestos of scattering prevention agents and investigate the change in penetration depth and viscosity according to the dilution rate of anti-scattering agents diluted with distilled water. Methods: Five different types of scattering prevention agents were spread on plate-type asbestos ceiling materials. The penetration depth of each coated ceiling material was measured by energy dispersive spectroscopy (EDS) analysis, based on X-ray fluorescence (XRF) results of the non-coated ceiling materials. Test equipment installed the ceiling materials and 60 minutes were collected at a flow rate of $10{\ell}/min$ at a filter of 25 mm. Results: An EDS analysis of the cross-section of ceiling materials constructed with a scattering prevention agent revealed that potassium is detected in the process of penetrating hardener solidification and this element could be an indicator for infiltration. When anti-scattering agents with different viscosities were constructed and the penetration depth was analyzed by potassium detection assessment using EDS, the depth results with viscosities of 5.0, 2.5, and 1.9 cP were 98.5, 103, and $147{\mu}m$, respectively. Penetration performance improved with decrease in viscosity. Conclusions: For asbestos ceiling materials, it is concluded that a higher dilution rate of the scattering prevention agent leads to lower viscosity, and hence a deeper penetration depth from $156{\mu}m$ to 3 mm. The asbestos anti-scattering properties according to the penetration depth will be confirmed through further study.

• 수산해양기술연구
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• 제51권1호
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• pp.120-127
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• 2015

Morphological properties of dark banded rockfish (Sebastes inermis) were analysed to investigate its acoustic scattering characteristics. Total of 18 live samples was prepared for X-ray photos and collected morphological coordinates of their body and swim bladder shapes. Kirchhoff-ray mode model was used to calculate acoustic scattering pattern for broad-band frequency range. Inclination of swim bladder ranged from 17 to 30 and the averaged value was about $25.2^{\circ}$ (S.D.(standard deviation)=3.15). There were no any tendency of increase or decrease in volume and area ratio of swim bladder to fish body and ranged from 2.2 % to 4.43 % and 14.85 % to 21.31 %, respectively. The averaged value of volume and area ratio was 3.13 % (S.D.=0.52) and 17.6 % (S.D.=1.5). $b_{20}$ values were -69.01 for 38 kHz, -69.83 for 70 kHz, -70.17 for 120 kHz and -70.93 for 200 kHz, recpectively. Broadband acoustic patterns of dark banded rockfish for 20 ~ 200 kHz were similar among samples and they reflected size and morphological properties of fish species.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.1-4
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• 2004

Polycrystalline CdSe thin films were grown on ceramic substrate using a chemical bath deposition(CBD)method. They were annealed at various temperature and X-ray diffraction patterns were measured by X-ray diffractometer in order to study CdSe polycrystal structure. Using extrapolation method of X-ray diffraction patterns for the CdSe samples annealed in $N_2$ gas at $450^{\circ}C$ it was found hexagonal structure whose lattice parameters $a_0$ and $c_0$ were $4.302{\AA}$ and 7.014 ${\AA}$, respectively. Its grain size was about 0.3 ${\mu}m$. Hall effect on this sample was measured by Van der Pauw method and studied on carrier density and movility depending on temperature. From Hall data, the mobility was likely to be decreased by piezo electric scattering at temperature range of 33K and 200K, and by polar optical scattering at temperature range of 200K and 293K. We measured also spectral response, sensitivity$(\gamma)$, maximum allowable power dissipation and response time on these samples.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2348-2356
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• 2021

As a relatively new radiation imaging method, the cosmic-ray muon scattering imaging technology can be used to prevent nuclear smuggling and is of considerable significance to nuclear safety. Proposed in this paper is a new reconstruction algorithm based on density clustering, aiming to improve inspection quality with better performance. Firstly, this new algorithm is introduced in detail. Then in order to eliminate the inequity of the density threshold caused by the heterogeneity of the muon flux in different positions, a new flux correction method is proposed. Finally, three groups of simulation experiments are carried out with the help of Geant4 toolkit to optimize the algorithm parameters, verify the correction method and test the inspection quality under shielded condition, and compare this algorithm with another common inspection algorithm under different conditions. The results show that this algorithm can effectively identify and locate nuclear material with low misjudging and missing rates even when there is shielding and momentum precision is low, and the threshold correcting method is universally effective for density clustering algorithms.

• 한국통신학회논문지
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• 제27권1B호
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• pp.114-124
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• 2002

본 논문에서는 실내 전파환경에서의 페이딩을 분석하기 위하여 영상법 기반의 3차원 광선추적법에 패치산란모델을 첨가한 모델을 제시하였다. 영상법 기반의 광선추적법은 정확한 경로를 얻을 수 있다는 장점 때문에, 안테나의 빔패턴 및 편파, 그리고 전파의 진행에 따른 편파를 고려함으로써 페이딩 특성 분석이 가능하다. 또한 실내 구조물을 모델링하기 위한 패치산란모델은 패치형태의 직사각형 평면에 대한 RCS (Radar Cross Section)를 이용하여 입사에 대한 산란현상을 정의한 것으로써, 책상이나 테이블 같은 평면적인 실내 구조물에 대한 산란현상을 각각의 구조물에 대한 영상 안테나를 발생시키는 복잡한 과정 없이 간단하게 해석하기 위한 것이다. 제안된 모델은 신호강도 뿐만 아니라 채널의 페이딩 특성을 예측할 수 있기 때문에 안테나 종류별 편파 다이버시티 기법의 성능을 분석하는데 이용될 수 있다.