방사성 오염도 측정을 위한 광섬유 검출기 제작

김정호,주관식,Kim, Jeong-Ho,Joo, Koan-Sik 한국전기전자학회 2015 전기전자학회논문지 Vol.19 No.3

본 연구에서는 연구에서는 Ce:GAGG 섬광체, 광섬유 그리고 광전자증배관을 이용하여 광섬유 검출기를 제작하였다. 섬광체의 단결정 크기는 MCNPX 코드를 이용하여 섬광체 깊이에 따른 감마선 계수효율을 전산모사하여 $3{\times}3{\times}20mm^3$로 설정하였다. 제작된 검출기는 표준 감마선원인 $^{137}Cs$과 $^{133}Ba$을 이용하여 세기의 따른 선형성 평가와 거리 변화에 따른 계수량 변화 측정을 하였다. 그 결과 추세선식 R-square 값이 0.99741로 매우 좋은 응답선형성을 보였고, 거리에 따른 검출 특성 또한 MCNPX값과 비교하였을 때 2% 이하로 좋은 검출특성을 보였다. 또한 단일선원과 혼합선원에서의 감마선 에너지 분광 결과 $^{137}Cs$은 662keV에서 그리고 $^{133}Ba$은 356keV에서 감마선 에너지 피크를 확인하였다. 광섬유 검출기를 사용한다면 작업자의 작업시간과 피폭을 줄여줄 것으로 보인다. In this study, an optical fiber detector was constructed by using a Ce:GAGG scintillator, optical fiber, and photomultiplier. The single crystal size of the scintillator was set to $3{\times}3{\times}20mm^3$ after simulating the counting efficiency of gamma rays in the scintillator by using the MCNPX code. The constructed detector used the standard gamma ray sources $^{137}Cs$ and $^{133}Ba$ to measure radiation and analyze the spectral characteristics of gamma rays. The resulting trend curve showed excellent linearity with an R-squared value of 0.99741, and the detector characteristics were found to vary 2% or less with distance based on comparison with the MCNPX value. Furthermore, the spectroscopic analysis of the gamma ray energy from the single-ray and mixed-ray sources showed that $^{137}Cs$ had its peak energy at 662 keV, and $^{133}Ba$ had at 356 keV. It seems that if the fiber-optics detector is used, working hours and exposure of worker can be reduced.

플라스틱 섬광체를 이용한 방사선 검출기의 검출 효율을 높이기 위한 섬광체 연마 기술 연구

김정호,주관식,Kim, Jeong-Ho,Joo, Koan-Sik 한국전기전자학회 2014 전기전자학회논문지 Vol.18 No.4

Scintillators were polished in four steps using polishing paper, to reduce the optical loss occurring at their cross section when radiation detectors are fabricated with plastic scintillators. We studied the correlation between the polishing steps and detection efficiency and assessed the detection characteristics that are dependent in the polishing steps. Our results showed that the detection efficiency increased by approximately 7.75 times for a detector that used a scintillator polished in four steps, compared to a detector that used an depolished scintillator. For detectors fabricated using scintillators polished in different steps, better detection characteristics were obtained in terms of the activity, distance, and location of radiation, compared to detectors fabricated with an depolished scintillator. 본 연구는 방사선 검출용 플라스틱 섬광체 검출기의 검출효율을 높이기 위한 섬광체 연마에 관한 연구이다. 플라스틱 섬광체를 이용한 검출기를 제작하여 4단계의 연마 과정으로 섬광체 절단면에서 광손실을 감소시켰다. 이때 연마단계와 검출 효율에 대한 상관관계를 구하여 검출 특성을 평가하였다. 연마단계에 따른 검출 효율을 측정한 결과 연마하지 않은 섬광체와 비교하여 4단계의 연마 과정을 모두 연마한 섬광체를 이용한 검출기의 검출 효율이 최대 7.57배 증가하는 것을 확인하였고 각 단계 별로 연마한 섬광체를 이용하여 제작한 검출기에서도 방사선의 세기, 거리, 위치에 대한 검출 특성에서도 연마하지 않은 섬광체에 비하여 좋은 검출 특성을 보였다.

다목적 동시측정 장치 개발에 의한 원자핵 구조 연구(I) - $^{75}As$의 감마 전이에 대한 전자기적 특성 -

정원모,정갑수,주관식,나상균,황한열,Chung, Won-Mo,Chung, Kap-Soo,Joo, Koan-Sik,Na, Sang-Kyun,Hwang, Han-Yull 대한방사선방어학회 1993 방사선방어학회지 Vol.18 No.1

홀수 핵종인 $^{75}As$의 핵 구조를 분광학적 방법으로 연구하기 위하여 $^{75}Se$의 전자 포획에 의하여 방출되는 감마선에 대해 단일 감마선 측정과 감마-감마 동시측정 실험을 하였다. 본 실험에서 구한 각 상관관계 계수는 $A_{22}=-0.452{\pm}0.017,\;A_{44}=0$이고 279.5keV 전이 감마선에 대한 혼합비는 ${\delta}=-0.586{\pm}0.017$을 얻었다. 또한 낮은 준위에서의 에너지의 상대 강도를 정확히 측정한 후 이를 이용하여 환산 행렬 요소들을 계산한 후 단일 입자 모형의 관점에서 hindrance factor를 구했다. 그 결과 279.5 keV 감마 전이의 다중극도는 74.44%의 Ml 전이와 25.56%의 E2 전이를 포함한 혼합 전이이며 5/2 준위의 밴드구조를 $f_{5/2}$ proton준위에 바탕을 둔 1/2 [310]으로 결정하였다. The gamma-gamma coincidence measurements and angular correlation measurement associated with the electron capture of $^{75}Se$ have been carried to understand the structure for the odd nuclei $^{75}As$ with two HPGe detectors. As a result, we could determined the band structure of 5/2 state to be of 1/2 [310] band which is based on $f_{5/2}$ proton state. Also we obtained the multipole admixture in the state of 279.5keV by using the mixing ratios of $121.1{\sim}279.5keV$ cascade. Subsequently, it is determined that 25.56% electric quadrupole transition is involved in the state of 279.5keV.

수중 내 베타선 모니터링 센서 개발을 위한 기초연구

박혜민 ( Hye Min Park ),주관식 ( Koan Sik Joo ) 한국센서학회 2016 센서학회지 Vol.25 No.5

In this study, a beta monitoring sensor was developed as a part of basic research for quantitative beta monitoring underwater, and its performance was evaluated using a calibration source. A beta detection sensor was manufactured by using SiPM(silicon photomultiplier) and CaF₂:Eu, YAG:Ce, YAP:Ce scintillator. A large-area light guide was introduced to improve beta-ray detection efficiency. As calibration sources, the Beta source ⁹⁰Sr, which is the main fission product of a nuclear accident, and the gamma source ¹³⁷Cs are used. In the performance evaluation, it is confirmed that scintillator CaF₂:Eu gives the highest beta-ray detection response. Compared to gamma ray, beta-ray detection responsivity and detection efficiency are verified. Therefore, this study is expected to contribute to basic research in the development of an underwater beta-ray monitoring system.

수중 방사선 감시체계 구축을 위한 실시간 방사선 준위 모니터링 센서 개발

박혜민 ( Hye Min Park ),주관식 ( Koan Sik Joo ) 한국센서학회 2015 센서학회지 Vol.24 No.2

In the present study, we developed a real-time radiation-monitoring sensor for an underwater radiation-monitoring system and evaluated its effectiveness using reference radiation sources. The monitoring sensor was designed and miniaturized using a silicon photomultiplier (SiPM) and a cerium-doped-gadolinium-aluminum-gallium-garnet (Ce:GAGG) scintillator, and an underwater wireless monitoring system was implemented by employing a remote Bluetooth communication module. An acrylic water tank and reference radiation sources (137Cs, 90Sr) were used to evaluate the effectiveness of the monitoring sensor. The underwater monitoring sensor’s detection response and efficiency for gamma rays and beta particles as well as the linearity of the response according to the gammaray intensity were verified through an evaluation. This evaluation is expected to contribute to the development of base technology for an underwater radiation-monitoring system.

YSO 섬광체의 기하학적 구조에 따른 감마선 검출기의 검출 특성 연구

김정호(Kim, Jeong-Ho),주관식(Joo, Koan-Sik) 한국전기전자학회 2016 전기전자학회논문지 Vol.20 No.2

본 연구에서는 3mm×3mm×2mm, 3mm(Dia)×15mm, 3mm(Dia)×20mm, 10mm(Dia)×20mm. YSO 섬광체와 광전자증배관을 결합하여 검출기를 제작하였다. 또한 10mm의 지름을 가진 섬광체는 LightTools를 이용하여 최적화한 광가이드와 결합하였다. 광가이드의 두께는 2mm이며 입사부는 섬광체 크기와 같은 10mm이고 출사부는 다른 섬광체와 같은 3mm이다. 제작된 검출기는 표준 감마선원인 ¹³⁷Cs를 이용하여 분광 특성을 분석하였다. 그 결과 662keV에서 각각의 에너지 분해능이 14.46%, 21.10%, 10.71%, 나왔으며 10mm의 지름과 20mm의 길이를 가진 섬광체에 광가이를 결합한 섬광체가 7.48%로 분해능이 가장 좋게 나왔다. In this study, gamma radiation detectors are created by integrating the following combinations of different YSO scintillators and PMT(photomultiplier-tubes) respectively: 3mm×3mm×2mm, 3mm(Dia)×15mm, 3mm(Dia)×20mm, 10mm(Dia)×20mm. In addition, the scintillator with a 10mm diameter was integrated with a light guide with a 2mm thickness, 10mm entry and 3mm exit, using LightTools. The constructed detector used the standard gamma ray sources ¹³⁷Cs(662keV) to analyze the spectral characteristics of gamma rays. The results indicate that at 662keV, the energy resolutions were 14.46%, 21.10%, and 10.71% for the first three combinations respectively. The best results were recorded for the 10mm(Dia)×20mm detector with light guide, which had an energy resolution of 7.48%

Ar, He 및 $N_2$ 가스의 $\alpha$-입자 저지능과 저지 단면적 측정

이정훈,황재광,황한열,정원모,주관식,Lee, Jung-Hoon,Hwang, Jae-Kwang,Hwang, Han-Yull,Chung, Won-Mo,Joo, Koan-Sik 대한방사선방어학회 1988 방사선방어학회지 Vol.13 No.2

3MeV에 서 5.4MeV 사이의 $\alpha$-입자에 대한 저지능과 저지 단면적을 He, Ar, 및 $N_2$ 가스에 대해서 측정했다. Srivastava의 저지능 공식을 본 실험결과에 적용시켜 그 타당성을 알아보았다. 그결과 Ar의 경우는 매우 잘 일치됨을 보여주며, He의 경우는 27-28%, $N_2$의 경우는 13-26%의 불일치를 보여주고 있다. The energy losses of ${\alpha}$-particle with 3 to 5.4 MeV energy were measured as a function of gas absorber thickness and ${\alpha}$-particle energy in three light gaseous media; He, Ar, and $N_2$. The stopping powers and stopping cross-sections were determined by analyzing these data. For Ar gas, the experimental values are very well consistent with the corresponding values of Srivastava's stopping-power theory with the condition of the completely and partially stripped ion. For $N_2$ and He gases, these experimental values express the inconsistencies of about $13{\sim}36%$ and $27{\sim}28%$, respectively.

Laminography 용법에 의한 반도체 손상 저감 필터 연구

박찬종(Chan-Jong Park),박혜민,김정호,박기현,주관식(Sik-Koan Joo) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.6

NaI ( T1 ) 섬광결정과 위치민감형 광전자증배관을 이용한 유방암 진단용 소형 감마카메라 개발

김종호,최용,권홍성,김희중,김상은,최연성,이경한,김문회,주관식,김병태 ( Jong Ho Kim,Yong Choi,Hong Seong Kwon,Hee Joung Kim,Sang Eun Kim,Yearn Seong Choe,Kyung Han Lee,Moon Hae Kim,Koan Sik Joo,Byung Tae Kim ) 대한핵의학회 1998 핵의학 분자영상 Vol.32 No.4

Purpose: The conventional gamma camera is not ideal for scintimammography because of its large detector size ( 500 mm in width) causing high cost and low image quality. We are developing a small gamma camera dedicated for breast imaging. Materils and Methods: The small gamma camera system consists of a NaI (Tl) crystal (60 mm X60 mm X6 mm) coupled with a Hamamatsu R3941 Position Sensitive Photomultiplier Tube (PSPMT), a resister chain circuit, preamplifiers, nuclear instrument modules, an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a standard resistive charge division which multiplexes the 34 cross wire anode channels into 4 signals (X, X, Y, Y ). Those signals were individually amplified by four preamplifers and then, shaped and amplified by amplifiers. The signals were discriminated and digitized via triggering signal and used to localize the position of an event by applying the Anger logic. Results: The intrinsic sensitivity of the system was approximately 8,000 counts/.'ec/pCi. High quality flood and hole mask images were obtained. Breast phantom containing 2-7 mm diameter spheres was successfully imaged with a parallel hole collimator. The image displayed accurate size and activity distribution over the imaging field of view. Conclusion: We have succesfully developed a small gamma camera using NaI(T1)-PSPMT and nuclear instrument modules. The small gamma camera developed in this study might imprnve the diagnostic accuracy of scintimammography by optimally imaging the breast. (Korean J Nucl Med 1998;32:365-73)

뇌파를 이용한 2축머신 제어시스템에 관한 연구

김동완(Dong-Wan Kim),백승화(Seung-Hwa Beack),문대엽(D.Y Moon),주관식(Koan-Sik Joo) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.7(초록집)