• Nuclear Engineering and Technology
• /
• 제55권3호
• /
• pp.1031-1035
• /
• 2023

Neutron is an indirectly ionizing particle without charge, which is normally measured by detecting reaction products. Neutron detection system based on measuring gadolinium-converted gamma-rays is a good way to monitor the neutron because the representative prompt gamma-rays of gadolinium have low energies (79, 89, 182, and 199 keV). Low energy gamma-rays and their high attenuation coefficient on materials allow the simple design of a detector easier to manufacture. Thus, we designed a cadmium zinc telluride detector to investigate feasibility of simultaneous detection of gamma-rays and neutrons by using the Monte-Carlo simulation, which was divided into two parts; first was gamma-detection part and second was gamma- and neutron-simultaneous detection part. Consequently, we confirmed that simultaneous detection of gamma-rays and neutrons could be feasible and valid, although further research is needed for adoption on real detection.

• 전기학회논문지
• /
• 제63권9호
• /
• pp.1253-1258
• /
• 2014

In this paper, we propose the fast and efficient detection method using the continuous measurement technique for the gamma-ray signal acquisition. This method is improved than the conventional method for the getting information of the radiation distribution. First, we implement the stereo radiation detection system using gamma-ray sensors and the motion controller. We apply continuous measurement technique to the gamma-ray detector and conduct gamma-ray irradiation test for the comparison of detection techniques. The results show that the continuous measurement technique has the high efficient performance than the conventional method.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2016년도 추계학술대회
• /
• pp.942-943
• /
• 2016

스테레오 감마선 탐지장치는 감마선을 신호를 측정하여 위치값을 통한 2차원의 감마선 영상을 생성 한후, 가시광영상과 중첩하여 실제 공간상의 감마선 분포를 나타낸다. 스테레오 감마선 탐지장치는 감마선 탐지센서를 포함하는 탐지부와 감마선 신호를 검출하는 신호측정부 그리고 탐지부의 위치를 제어하기 위한 모션제어부로 구성된다. 본 논문에서는 개별적으로 구성된 각각의 모듈을 효율적으로 운용하기 위한 시스템 운용 알고리즘을 개발하였고, 이를 통해 감마선 조사시험장에서 감마선에 대한 영상화 및 분포정보 출력을 확인하였다.

• 한국정보통신학회논문지
• /
• 제20권10호
• /
• pp.2001-2006
• /
• 2016

감마선 공간 탐지 장치는 감마선원을 스캔하여 영상화 한 후 스테레오 영상처리기술을 적용하여 탐지선원까지의 거리를 측정한다. 또한 실제 공간의 방사선원에 대한 분포 정보를 제공해 준다. 본 논문에서는 감마선 탐지장치가 3차원 공간상에서 장치로부터 선원을 찾기 위해 스캔하는 탐지 시간을 단축 시킬 수 있도록 감마선 탐지 고속화 알고리즘을 구현하였다. 그리고 감마선 조사 시험장에서 실험을 통해 그 성능을 검증하였다. 탐지시험 결과 고속 탐지를 위한 알고리즘을 적용할 경우 단일선원을 탐지할 경우 좌 우 스테레오 영상 획득 시보다 약 35% 의 탐지 시간을 단축시킬 수 있음을 확인하였다. 또한 사용자에게 방사선 공간분포 정보를 효율적으로 전달하기 위한 감마선원 분포의 입체 가시화를 구현하여 방사선원에 대한 정보를 제공할 수 있도록 하였다.

• Journal of Radiation Protection and Research
• /
• 제43권4호
• /
• pp.137-142
• /
• 2018

Background: Gamma-ray detectors having a thin window of a material with low atomic number can increase the true coincidence summing effects for radionuclides emitting X-rays or gamma-rays. This effect can make efficiency calibration or spectrum analysis more complicated. In this study, a Cu shield was tested as an X-ray filter to neglect the true coincidence summing effect by X-rays and gamma-rays in gamma-ray spectrometry, in order to simplify gamma-ray energy spectrum analysis. Materials and Methods: A Cu shield was designed and applied to an n-type high-purity germanium detector having an $X-{\gamma}$ summing effect during efficiency calibration. This was tested using a commercial, certified mixed gamma-ray source. The feasibility of a Cu shield was evaluated by comparing efficiency calibration results with and without the shield. Results and Discussion: In this study, the thickness of a Cu shield needed to avoid true coincidence summing effects due to $X-{\gamma}$ was tested and determined to be 1 mm, considering the detection efficiency desired for higher energy. As a result, the accuracy of the detection efficiency calibration was improved by more than 13% by reducing $X-{\gamma}$ summing. Conclusion: The $X-{\gamma}$ summing effect should be considered, along with ${\gamma}-{\gamma}$ summing, when a detection efficiency calibration is implemented and appropriate shielding material can be useful for simplifying analysis of the gamma-ray energy spectra.

• Nuclear Engineering and Technology
• /
• 제52권10호
• /
• pp.2151-2161
• /
• 2020

The study presents a review of research advancements in the field of gamma radiation detection systems for emergency radiation monitoring, particularly two major sub-systems namely (i) the radiation detector and (ii) the detection platform - air-borne and ground-based. The dynamics and functional characteristics of modern radiation detector active materials are summarized and discussed. The capabilities of both ground-based and aerial vehicle platforms employed in gamma radiation monitoring are deliberated in depth.

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

• Nuclear Engineering and Technology
• /
• 제54권11호
• /
• pp.3985-3995
• /
• 2022

The emergence of new nanoscale technologies has imposed significant challenges to designing reliable electronic systems in radiation environments. A few types of radiation like Total Ionizing Dose (TID) can cause permanent damages on such nanoscale electronic devices, and current state-of-the-art technologies to tackle TID make use of expensive radiation-hardened devices. This paper focuses on a novel and different approach: using machine learning algorithms on consumer electronic level Field Programmable Gate Arrays (FPGAs) to tackle TID effects and monitor them to replace before they stop working. This condition has a research challenge to anticipate when the board results in a total failure due to TID effects. We observed internal measurements of FPGA boards under gamma radiation and used three different anomaly detection machine learning (ML) algorithms to detect anomalies in the sensor measurements in a gamma-radiated environment. The statistical results show a highly significant relationship between the gamma radiation exposure levels and the board measurements. Moreover, our anomaly detection results have shown that a One-Class SVM with Radial Basis Function Kernel has an average recall score of 0.95. Also, all anomalies can be detected before the boards are entirely inoperative, i.e. voltages drop to zero and confirmed with a sanity check.

• Journal of Radiation Protection and Research
• /
• 제26권4호
• /
• pp.393-398
• /
• 2001

매년 병원에서 사용 후 폐기되는 비가연성 폐기물은 ${\gamma}$-선과 ${\beta}$-선을 방출하지만 방사능은 주변방사능 수준으로 매우 낮다. 이를 측정하기 위한 기존의 방법은 비효율적이고 복잡하므로, 좀더 간단한 방법이 긴요하다. 본 논문에서는 측정 방사선의 특성상 핵종에 따라 다른 측정방법을 사용하였는데, ${\gamma}$-선 방출 핵종은 표준시료로부터 효율곡선식을 도출하여 미지의 방사능을 측정하였다 ${\beta}$-선 방출 핵종은 Monte Carlo 시뮬레이션을 통해 계측 효율을 예측하고 표면장벽형계측기로 측정하여 미지의 방사능 양을 결정하는 새로운 방법을 제시하였다. 연구결과에 의하면 이론적 계산치와 표면장벽형 계측기를 이용하면 전처리를 필요로하는 액체섬광계수기를 이용하지 않고 또한 계측효율을 결정하기 위한 비경제적인 표준시료 측정시험과정 없이도 저에너지 방사선을 약 17% 오차 범위내에서 결정할 수 있다고 판단된다.

• Nuclear Engineering and Technology
• /
• 제53권12호
• /
• pp.4093-4097
• /
• 2021

This study presents a new dead-time measurement method using the gamma attenuation law and generalized dead-time models for nuclear gamma-ray detectors. The dead-time of the NaI(Tl) detection system was obtained to validate the new dead-time determination method using very thin lead and polyethylene absorbers. Non-paralyzing dead-time was found to be 8.39 ㎲, and paralyzing dead-time was found to be 8.35 ㎲ using lead absorber for NaI(Tl) scintillator detection system. These dead-time values are consistent with the previously reported dead-time values for scintillator detection systems. The gamma build-up factor's contribution to the dead-time was neglected because a very thin material was used.