• 한국기계가공학회지
• /
• 제18권8호
• /
• pp.60-66
• /
• 2019

This study aims to develop and manufacture a device for inspecting impurities in a sealed aluminum container using an X-ray technique. Two X-ray oscillators and detectors are used to detect the entire sample. The stage for sample movement was fabricated using two high-voltage generators and X-ray detectors arranged diagonally. In addition, the high-voltage generator is composed of a vacuum tube, a high-voltage generator, and circulating oil for cooling. It includes a control unit for controlling other equipment, a power supply unit, and a video output unit; the most important part of the X-ray is the X-ray generation part. In this study, a flat panel was used along with the aim of developing the detector part. In particular, the development of the scintillator introduced in this study is a primary focus. The developed scintillator can be combined with a lens and can then be assembled with a charge coupled device (CCD) sensor.

• 대한방사선기술학회지:방사선기술과학
• /
• 제42권1호
• /
• pp.67-75
• /
• 2019

Grating interferometry based imaging technology is a kind of radiation imaging system, which can acquire not only absorption image but also phase difference and dark field image using the Talbot pattern. However, because of the technological difficulties and high cost of fabricating the gratings that make up the system, much efforts are being made to look for ways to replace them. The is a preliminary study to see how the Talbot pattern transfer through various kinds of scintillators and if the optical grating can be a way to replace the conventional absorption gratings. The geometry of the interferometer, the scintillator model, and the scintillator thickness are the main inputs for our simulation. We have used the concept of modulation for quantitative analysis of the contrast ratio of the Talbot pattern. This research is expected to provide very useful information on the design of optical gratings, which is an alternative way to analyze the Talbot pattern, which we have filed a patent on.

• Nuclear Engineering and Technology
• /
• 제54권3호
• /
• pp.1024-1029
• /
• 2022

Composite scintillation screens on a base of Gd_1.2Y_1.8Ga_2.5Al_2.5O₁₂:Ce (GYAGG) scintillator have been evaluated for neutron detection. Besides the powdered scintillator, the composite includes ⁶LiF particles; both are merged with a binder and deposited onto the light-reflecting aluminum substrate. Results obtained demonstrates that screens are suitable for use with a silicon photomultiplier readout to create a prospective solution for a compact and low-cost thermal neutron sensor. Composite GYAGG/⁶LiF scintillation screen shows a pretty matched sensitivity and γ-background rejection with a widely used ZnS/⁶LiF screens however, possesses forty times faster response.

• Nuclear Engineering and Technology
• /
• 제55권9호
• /
• pp.3206-3212
• /
• 2023

We developed a miniaturized multi-dimensional radiation sensor system consisting of an inorganic scintillator array and plastic optical fibers. This system can be applied to remotely obtain the radioactivity distribution and identify the radionuclides in radioactive waste by utilizing a scanning method. Variation in scintillation light was measured in two-dimensional regions of interest and then converted into radioactivity distribution images. Outliers present in the images were removed by using a digital filter to make the hot spot location more accurate and cubic interpolation was applied to make the images smoother and clearer. Next, gamma-ray spectroscopy was performed to identify the radionuclides, and three-dimensional volume scanning was also performed to effectively find the hot spot using the proposed array sensor.

• Nuclear Engineering and Technology
• /
• 제55권3호
• /
• pp.1045-1051
• /
• 2023

In this study, we fabricated a liquid light-guide-based radiation sensor with a LaBr₃:Ce scintillator for remote gamma-ray spectroscopy. We acquired the energy spectra of Cs-137 and Co-60 using the proposed sensor, estimated the energy resolutions of the full energy peaks, and compared the scintillation light output variations. The major peaks of the radionuclides were observed in each result, and the estimated energy resolutions were similar to that of a general NaI(Tl) scintillation detector without a liquid light guide. Moreover, we showed the relationships of energy resolution and analog-to-digital channel regarding the number of photoelectrons produced and confirmed the effects of light guide length on remote gamma-ray spectroscopy. The proposed sensor is expected to be utilized to perform remote gamma-ray spectroscopy for distances of 3 m or more and would find application in many fields of nuclear facilities and industry.

• 한국방사선학회논문지
• /
• 제13권4호
• /
• pp.661-666
• /
• 2019

확산형 콜리메이터는 촬영 대상을 축소 촬영하거나 넓은 관심영역을 작은 감마카메라를 사용하여 검출하기 위해서 사용한다. 확산형 콜리메이터와 블록형 섬광체 및 픽셀형 섬광체 배열을 사용하는 감마카메라에서 방사선원이 관심영역 주변에 위치할 때 섬광체 표면에 감마선이 대각선으로 입사하게 되면, 섬광체 깊이 방향으로 대각선으로 검출되기 때문에 공간 분해능이 저하된다. 본 연구에서는 이러한 관심영역 외곽에서의 공간 분해능을 향상하기 위한 새로운 시스템을 설계하였다. 사다리꼴 픽셀형 섬광체를 사용하여 각 섬광 픽셀을 콜리메이터 구멍의 각도와 크기에 맞게 일치하도록 구성하면, 감마선이 섬광체의 여러 깊이에서 반응하더라도, 하나의 섬광 픽셀 위치로 영상화 할 수 있다. 즉, 대각선 방향의 여러 지점에서 검출되더라도, 감마선은 하나의 섬광 픽셀과 상호 작용하기 때문에 공간 분해능의 저하가 발생하지 않는다. Geant4 Application for Tomographic Emission (GATE) 시뮬레이션을 통해 블록형 섬광체를 사용한 감마카메라와 사다리꼴 픽셀형 섬광체를 사용한 감마카메라를 설계하여 공간 분해능을 비교 평가하였다. 관심영역 외곽에서 발생한 감마선을 통해 획득한 영상에서 공간 분해능은 블록형 섬광체를 사용한 감마카메라에서는 4.05 mm였고, 사다리꼴 픽셀형 섬광체를 사용한 감마카메라에서는 2.97 mm의 공간 분해능을 보였다. 사다리꼴 셀형 섬광체를 사용한 시스템에서 26.67% 공간 분해능이 향상됨을 확인할 수 있었다.

• 세라미스트
• /
• 제17권4호
• /
• pp.37-42
• /
• 2014

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2018년도 추계학술논문요약집
• /
• pp.511-512
• /
• 2018

• Nuclear Engineering and Technology
• /
• 제49권7호
• /
• pp.1483-1488
• /
• 2017

In order to predict and control the environmental and health impacts of ionizing radiation in environmental sources such as groundwater, it is necessary to identify the radionuclides present. Beta-emitting radionuclides are frequently identified by measuring their characteristic energy spectra. The present work shows that self-attenuation effects from volume sources result in a geometry-dependent shift in the characteristic spectra, which needs to be taken into account in order to correctly identify the radionuclides present. These effects are shown to be compounded due to the subsequent shift in the photon spectra produced by the detector, in this case an inorganic solid scintillator ($CaF_2:Eu$) monitored using a silicon photomultiplier. Using tritiated water as an environmentally relevant, and notoriously difficult to monitor case study, analytical predictions for the shift in the energy spectra as a function of depth of source have been derived. These predictions have been validated using Geant4 simulations and experimental results measured using bespoke instrumentation.

• 센서학회지
• /
• 제25권5호
• /
• pp.333-336
• /
• 2016

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 $CaF_2$: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 $^{90}Sr$, which is the main fission product of a nuclear accident, and the gamma source $^{137}Cs$ are used. In the performance evaluation, it is confirmed that scintillator $CaF_2:Eu$ 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.