• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.612-615
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• 2003

In this paper, a design of radiation detector for gamma column scanner is introduced. Distillation column is important unit in Petro-chemical industries, and its on-line diagnose is very important. To get density profile measured by the radiation transmitted through column is well method for on-line diagnose as gamma scanning. For this purpose radiation detection circuit, radiation source and mechanical system for moving source and detector are required. Conventional radiation detection circuit for this application is sensitive to electric noise because of interface between the radiation circuit and the controller for mechanical system. The radiation detection system introduced here is using loop coil instead of slip ring to remove contact noise. Radiation detection system designed here for gamma scanning consist of BGO detector, high voltage circuit, PHA circuit and FSK modem. The BGO detector is used as radiation sensor, high voltage circuit and peak height analysis circuit is essential to process the signal generated from BGO detector. Micro controller convert measured data into ASCII data. FSK modem transmit ASCII data. Transmitted ASCH data is picked up in antenna coil and processed for combined function with mechanical system. This method gives good result by isolating the controlling circuit of mechanical system from radiation detecting circuit which is sensitive to noise.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.771-774
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• 1992

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 하계학술발표회
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• pp.98-99
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• 2003

PIN photodiode has been used in solid-state detector for x-ray detection as a photosensor of visible light from scintillator. Since the light from CWO is short wavelength having peak at 490nm, the light is absorbed within a very shallow layer near the surface of the photodiode before arriving at the depletion layer and does not contribute to the signal. In designing the PIN photodiode, it is important to make the p-layer as shallow as possible. (omitted)

• 한국진공학회지
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• 제20권1호
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• pp.35-41
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• 2011

본 연구에서는 InAs/GaSb 응력초격자(SLS)의 계면 흡착(soaking)에 의한 응력변조 효과를 X선회절(XRD)을 통하여 분석하였다. As과 Sb 흡착에 의하여 유도된 응력의 변화는 XRD 곡선의 기판피크과 0차 위성피크 사이의 분리각으로부터 조사하였으며, As/InAs 흡착은 약간의 GaAs-like 계면층을 유발하는 반면, Sb/GaSb 흡착은 InSb-like 계면상을 유도하는 것으로 분석되었다. Pendellosung 간섭진동의 Fourier 변환 곡선을 이용하여, [InAs/GaSb]-SLS 성장에서 결정성이 가장 우수한 최적 As/InAs와 Sb/GaSb의 흡착시간은 각각 2 sec와 10 sec임을 밝혔다. InAs${\rightarrow}$GaSb 계면에 As과 Sb를 동시에 흡착시킨 SLS에서 XRD 위성피크가 2개로 분할되는 특이한 쌍정현상이 관측되었는데, 이것은 계면에서 In${\leftrightarrow}$Ga 및 Sb${\leftrightarrow}$As 상호혼합에 의한 InSbAs와 GaAsSb의 2종의 결정상이 공존함으로써 발생한 현상으로 추정된다.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1421-1430
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• 2022

The computation of the solid angle and the detector efficiency is considering to be one of the most important factors during the measuring process for the radioactivity, especially the cylindrical γ-ray NaI(Tl) detectors nowadays have applications in several fields such as industry, hazardous for health, the gamma-ray radiation detectors grow to be the main essential instruments in radiation protection sector. In the present work, a generic numerical simulation method (NSM) for calculating the efficiency of the γ-ray spectrometry setup is established. The formulas are suitable for any type of source-to-detector shape and can be valuable to determine the full-energy peak and the total efficiencies and P/T ratio of cylindrical γ-ray NaI(Tl) detector setup concerning the truncated conical radioactive source. This methodology is based on estimate the path length of γ-ray radiation inside the detector active medium, inside the source itself, and the self-attenuation correction factors, which typically use to correct the sample attenuation of the original geometry source. The calculations can be completed in general by using extra reasonable and complicate analytical and numerical techniques than the standard models; especially the effective solid angle, and the detector efficiency have to be calculated in case of the truncated conical radioactive source studied condition. Moreover, the (NSM) can be used for the straight calculations of the γ-ray detector efficiency after the computation of improvement that need in the case of γ-γ coincidence summing (CS). The (NSM) confirmation of the development created by the efficiency transfer method has been achieved by comparing the results of the measuring truncated conical radioactive source with certified nuclide activities with the γ-ray NaI(Tl) detector, and a good agreement was obtained after corrections of (CS). The methodology can be unlimited to find the theoretical efficiencies and modifications equivalent to any geometry by essential sufficiently the physical selective considered situation.

• Nuclear Engineering and Technology
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• 제52권6호
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• pp.1271-1276
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• 2020

The geometrical efficiency of a source-to-detector configuration is considered to be necessary in the calculation of the full energy peak efficiency, especially for NaI(Tl) and HPGe gamma-ray spectroscopy detectors. The geometrical efficiency depends on the solid angle subtended by the radioactive sources and the detector surfaces. The present work is basically concerned to establish a new mathematical approach for calculating the solid angle and geometrical efficiency, based on conversion of the geometrical solid angle of a non-axial radioactive point source with respect to a circular surface of the detector to a new equivalent geometry. The equivalent geometry consists of an axial radioactive point source with respect to an arbitrary elliptical surface that lies between the radioactive point source and the circular surface of the detector. This expression was extended to include coaxial radioactive circular disk source. The results were compared with a number of published data to explain how significant this work is in the efficiency calibration procedure for the γ-ray detection systems, especially in case of using isotropic radiating γ-ray sources in the form of point and disk shapes.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2601-2606
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• 2020

In this study, we expanded the performance of the existing EXVol code and performed empirical experiments and calculations. A high-resolution gamma spectroscopy system was constructed, and a standard point source and a standard volume source were measured with an HPGe detector with 43.1% relative efficiency. EXVol was verified by quantitative comparison of the detection efficiencies determined by measurements and calculations. To introduce the concept of the detector scanning that occurs in the actual measurement into the EXVol code, a collimator was placed between the source and detector. The detection efficiency was determined in the asymmetric arrangement of the source and detector with a collimator. A collimator made of lead with a diameter of 15 mm and a thickness of 50 mm was installed between the source and the detector to determine the detection efficiency at a specific location. The calculation result was contour plotted so that the distribution of detection efficiency could be visually confirmed. The relative deviation between the measurements and calculations for the coaxial and asymmetric structures was 10%, and that for the collimation structure was 20%. The results of this study can be applied to research using γ-ray measurements.

• 천문학회지
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• 제30권1호
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• pp.1-11
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• 1997

Near infrared JHK magnitudes are presented for two hundred two high proper motion stars. We have observed high proper motion stars in the near-infrared bands(JHK) using the COB detector on the Kitt Peak 1.3m, 2.1m and 4m telescopes. The observations and data reduction procedures are described. The infrared color magnitude diagram and color-color diagrams for the program stars are presented.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.323-325
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• 2015

본 논문에서는 휴대용 방사능 검출기를 디지털로 구현하기 위하여 아날로그 부 시간영역에서 사용되던 Pulse shaper의 기능을 소프트웨어만으로 커버 할 수 있는 알고리즘을 제안한다.

• 한국의학물리학회지:의학물리
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• 제33권4호
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• pp.129-135
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• 2022

Purpose: A full-energy-peak (FEP) efficiency correction is required through a Monte Carlo simulation for accurate radioactivity measurement, considering the geometrical characteristics of the detector and the sample. However, a relative deviation (RD) occurs between the measurement and calculation efficiencies when modeling using the data provided by the manufacturers due to the randomly generated dead layer. This study aims to optimize the structure of the detector by determining the dead layer thickness based on Monte Carlo simulation. Methods: The high-purity germanium (HPGe) detector used in this study was a coaxial p-type GC2518 model, and a certified reference material (CRM) was used to measure the FEP efficiency. Using the MC N-Particle Transport Code (MCNP) code, the FEP efficiency was calculated by increasing the thickness of the outer and inner dead layer in proportion to the thickness of the electrode. Results: As the thickness of the outer and inner dead layer increased by 0.1 mm and 0.1 ㎛, the efficiency difference decreased by 2.43% on average up to 1.0 mm and 1.0 ㎛ and increased by 1.86% thereafter. Therefore, the structure of the detector was optimized by determining 1.0 mm and 1.0 ㎛ as thickness of the dead layer. Conclusions: The effect of the dead layer on the FEP efficiency was evaluated, and an excellent agreement between the measured and calculated efficiencies was confirmed with RDs of less than 4%. It suggests that the optimized HPGe detector can be used to measure the accurate radioactivity using in dismantling and disposing medical linear accelerators.