• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.1024-1029
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• 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.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1371-1374
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• 1997

We had developed the on-line environmental monitoring system which has installed around Kori Nuclear Power Plants and will be taken the place of the existing system. The system consists of a main computer and 11 sets of radiation monitoring post equipments. Nal(Tl) scintillation detectro was adopted in addition to ion-chamber detector and implemented with DCU(Dose Conversion Unit) and SCA(Single Channel Analyzer). Compared with the existing system, it has revised feature in the radiation measurements which are detection of artificial radioactivity and 2-ways of the radiatiion detectors. The field test trsults show that the developed radiation detecting equipments can measure environmental radiation withn 5.0% of the theoretical value.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1253-1258
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• 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.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.35-37
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• 2002

Conceptual design of the next generation PET with both high sensitivity and high spatial resolution has been performed. A detector unit using a depth encoding scheme was designed and constructed for trial. The unit consists of four Gd$_2$SiO$\sub$5/:Ce crystal blocks in a 2x2x4 array coupled to a position-sensitive photomultiplier tube having metal channel dynodes and 4x4 multi-anodes. Our proposed detector is a very reliable and simple solution suitable for volume PET devices since the proposed depth encoding scheme does not need additional photo-detectors.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.511-515
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• 2020

In this study, we evaluated image quality for new Gadolinium Aluminum Gallium Garnet (GAGG) scintillation material based on the Geant4 Application for Tomographic Emission (GATE) simulation tool. The gamma camera detectors with GAGG and NaI scintillation were designed. In particular, we modeled modified body phantom by National Electrical Manufacturers Association International Electrotechnical Commission to evaluate the simulated images. To analysis the image performance, the contrast to noise ratio (CNR) and coefficient of variation (COV) were used by drawn the region of interests, respectively. Based on the CNR and COV results, the CNR value for GAGG material is higher approximately 17 % than NaI material. In addition, the COV value for GAGG material is lower approximately 17 % than NaI material. In conclusion, we confirmed the performnace of GAGG based gamma camera is useful to improve the image quality for the nuclear medicine instrumentation.

• Progress in Medical Physics
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• v.27 no.1
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• pp.37-45
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• 2016

In proton therapy, in vivo proton beam range verification is very important to deliver conformal dose to the target volume and minimize unnecessary dose to normal tissue. For this purpose, a multi-slit prompt-gamma camera module made of 24 scintillation detectors and 24-channel signal processing system is under development. In the present study, we have developed and tested a dual-mode signal processing system, which can operate in the energy calibration mode and the fast data acquisition mode, to process the signals from the 24 scintillation detectors. As a result of performance test, using the energy calibration mode, we were able to perform energy calibration for the 24 scintillation detectors at the same time and determine the discrimination levels for the detector channels. Further, using the fast data acquisition mode, we were able to measure a prompt-gamma distribution induced by a 45 MeV proton beam. The measured prompt gamma distribution was found similar to the proton dose distribution at the distal fall-off region, and the estimated beam range was $17.13{\pm}0.76mm$, which is close to the proton beam range of 16.15 mm measured by an EBT film.

• Transactions on Electrical and Electronic Materials
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• v.4 no.3
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• pp.10-14
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• 2003

In this paper, we have introduced the x-ray detector built with a CsI:Na scintillation layer deposited on amorphous selenium. To determine the thickness of the CsI:Na layer, we have estimated the transmission spectra and the absorption of continuous x-rays in diagnostic range by using computer simulation (MCNP 4C). A x-ray detector with 65 ${\mu}m$-CsI:Na/30 ${\mu}m$-Se layer has been fabricated by a thermal evaporation technique. SEM and PL measurements have been performed. The dark current and x-ray sensitivity of the fabricated detector has been compared with that of the conventional a-Se detector with 100 ${\mu}m$ thickness. Experimental results show that both detectors exhibit a similar dark current, which was of a low value below $400 pA/cm^2$ at 10 V/${\mu}m$. However, the CsI:Na-Se detector indicates high x-ray sensitivity, roughly 1.3 times that of a conventional a-Se detector. Furthermore, a CsI:Na-Se detector with an aluminium reflective layer shows a 1.8 times higher x-ray sensitivity than an a-Se detector. The hybrid type detector proposed in this work exhibits a low dark current and high x-ray sensitivity, and, in particular, excellent linearity to the x-ray exposure dose.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3795-3802
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• 2022

NaI(Tl) scintillation materials are considered to be one of many materials that are used exclusively for γ-ray detection and spectroscopy. The gamma-ray spectrometer is not an easy-to-use device, and the accuracy of the numerical values must be carefully checked based on the rules of the calibration technique. Therefore, accurate information about the detection system and its effectiveness is of greater importance. The purpose of this study is to estimate, using an analytical-numerical formula (ANF), the purely geometric solid angle, geometric efficiency, and total efficiency of a cylindrical NaI(Tl) γ-ray detector with a side-through hole. This type of detector is ideal for scanning fuel rods and pipelines, as well as for performing radio-immunoassays. The study included the calculation of the complex solid angle, in combination with the use of various points like gamma sources, located axially and non-axially inside the through detector side hole, which can be applied in a hypothetical method for calibrating the facility. An extended γ-ray energy range, the detector, source dimensions, "source-to-detector" geometry inside the side-through hole, path lengths of γ-quanta photons crossing the facility, besides the photon average path length inside the detector medium itself, were studied and considered. This study is very important for an expanded future article where the radioactive point source can be replaced by a volume source located inside the side-trough hole of the detector, or by a radioactive pipeline passing through the well. The results provide a good and useful approach to a new generation of detectors that can be used for low-level radiation that needs to be measured efficiently.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.4
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• pp.296-303
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• 2003

A personal portable type electronic dosimeter using silicon PIN photodiode and small GM tube is recently attracting much attention due to its advantages such as an immediate indication function of dose and dose rate, alerting function, and efficient management of radiation exposure history and dose data. We designed and manufactured a semiconductor radiation detector aimed to directly measure X-ray and v-ray irradiated in silicon PIN photodiode, without using high-priced scintillation materials. Using this semiconductor radiation detector, we developed an active electronic dosimeter, which measures the exposure dose using pulse counting method. In this case, it has a shortcoming of over-evaluating the dose that shows the difference between the dose measured with electronic dosimeter and the dose exposed to the human body in a low energy area. We proposed an energy compensation filter and developed a dose conversion algorithm to make both doses indicated on the detector and exposed to the human body proportional to each other, thus enabling a high-precision dose measurement. In order to prove its reliability in conducting personal dose measurement, crucial for protecting against radiation, the implemented electronic dosimeter was evaluated to successfully meet the IEC's criteria, as the KAERI (Korea Atomic Energy Research Institute) conducted test on dose indication accuracy, and linearity, energy and angular dependences.

• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.122-123
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• 2011