• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.2
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• pp.105-111
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• 2018

Purpose Quality control of instrument takes up a large part in the Radioimmunoassays. The gamma-ray instrument, which is one of the important instruments in the laboratory, observes the condition and performance of instrument and performs quality control of the instrument by measuring the Normalization, Calibration, Background and etc. However, there are some automation instruments which can't measure the counting efficiency of gamma-ray meters, resulting in insufficient management in terms of performance evaluation of gamma-ray meters. Therefore, the purpose of this paper is to manage the quality control continuously and regularly by suggesting how to measure the counting efficiency of gamma-ray instruments. Materials and Methods In case of a comparative measurement method to a gamma-ray instrument dedicated to nuclear medical examination, the CPM and counting efficiency can be obtained after the measurement of normalization by inserting the I-125 $200{\mu}L$(CPM 50,000~500,000) into the test tube. With this CPM and counting efficiency values, it's possible to calculate the measurement of the DPM value and count the CPM from the automation instrument from the same source, and enter the DPM to calculate the counting efficiency using a comparative measurement method. Another method is to calculate the counting efficiency by estimating the half life using the radiation source information of the tracer in B test reagents of company A. Results According to the calculation formula using the DPM obtained by counting the normalization of gamma-ray meters, the detection efficiency was 75.16% for Detector 1, 76.88% for Detector 2, 77.13% for Detector 3, 75.36% for Detector 4 and 73.2% for Detector 5 respectively. Using another calculation formula estimated from the shelf life, the data of the detection efficiency from Detector 1 to Detector 5 were 74.9%, 75.1%, 76.5%, 74.9% and 73.2% respectively. Conclusion Although the accuracy of counting efficiencies of both methods are insufficient, this is considered to be useful for ongoing management of quality control if counting efficiency is managed after setting the acceptable ranges. For example, if the measurement efficiency is set to 70% or higher, the allowed %difference between measurements is within 3% and the %difference with the detector wall is set within 5%.

• Nuclear Engineering and Technology
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• v.42 no.1
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• pp.125-130
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• 2010

Sipping measurements were implemented at the Open Pool Australian Light water reactor (OPAL) to test for failure in reactor fuel elements. Fission product released by the fuel element into the pool water was measured using both High Purity Germanium (HPGe) detection via samples and a NaI(Tl) detection in-situ with the sipping device. Results from two fuel elements are presented.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.464-469
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• 1998

A coincidence gamma-ray spectroscopy method was applied to reduce the background radioactivity for measuring the activity of radioisotopes in a sample in the presence of environmental natural radioactivity. A HPGe detector was used for the coincident spectrum as a main detector and a NaI(Tl) scintillation detector for gating purposes as an associated detector. For coincidence spectroscopy the whole energy spectrum of associated detector was used instead of gate signals. The coincident events obtained from the gating spectrum was evaluated by a coincidence computer program in this study instead of timing circuit. In this work, the background of detection environment was reduced to factor 100 and peaks to be determined was reduced to factor 30 using the coincidence gamma-ray spectroscopy.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.2
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• pp.88-97
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• 2008

In this review paper, basic configurations of gamma detectors in SPECT and PET systems were reviewed together with key performance parameters of the imaging system, such as the detection efficiency, the spatial resolution, the contrast resolution, and the data acquisition time for quick understanding of the system-component relationship and future design of advanced systems. Also key elements of SPECT and PET detectors, such as collimators, gamma detectors were discussed in conjunction with their current and future trend. Especially development trend of new scintillation crystals, innovative silicon-based photo-sensors and futuristic room-temperature semiconductor detectors were reviewed for researchers who are interested in the development of future nuclear medical imaging instruments.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.4
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• pp.47-53
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• 1997

We fabricated gamma radiation detector using high resistive p-Cd$_{80}$Zn$_{20}$Te grown by high pressure bridgman method and forming au thin film electrode by chemically electroless deposition method. The device of Au/Cd$_{80}$Zn$_{20}$Te/Au is a typical MIM structure. The characteristic of current-voltage showed good linearity to 3kV/cm but it depend on the square of electric field over 3kV/cm. As the results of rutherford backscattering spectroscope(RBS) and auger spectroscope on the Au/Cd$_{80}$Zn$_{20}$Te, Au penetrated to the surface of Cd$_{80}$Zn$_{20}$Te detector absorbed slightly high energy radiation like a few hundred keV and showed good performance to detect low energy gamma ray.mma ray.

• Analytical Science and Technology
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• v.15 no.3
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• pp.248-255
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• 2002

The contents of ${\alpha}$-, ${\beta}$-, ${\gamma}$-, and $\delta$-tocopherols in sesame oils were determined by high performance liquid chromatography with UV detection. ${\alpha}$-Tocopherol contents ranged from 10.28 to 19.79 mg/g oil, ${\beta}$-tocopherol contents from 8.22 to 20.10 mg/g. However, both ${\gamma}$- and $\delta$-tocopherol were less than 1.49 mg/g or not detected. ${\gamma}$-Tocopherol was not detected from both unroasted white and black sesame seed oils. Significantly higher level of tocopherol in sesame oil than other oils is an evidence of the reason why it is highly stable and prevents oxidation. The tocopherol composition for twenty sesame oils was classified by using principal component analysis.

• Nuclear Engineering and Technology
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• v.34 no.1
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• pp.22-29
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• 2002

The angular correlation effect was investigated for Co-60 ${\gamma}$-ray spectroscopy by using HPGe detector and the effective angular correlation was theoretically calculated by considering the finite detector solid angle. For the calculation of effective angular correlation, the detection efficiency as a function of ${\gamma}$-ray incident direction was obtained by using Monte Carlo method and the first interaction model. The results and the methods used in the calculation are discussed.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.407-417
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• 2004

This study is to verify radiation detection method by using $\alpha$-spectroscopy and ${\gamma}$-spectroscopy for concretes and components which will be generated during the decommissioning of the uranium conversion plant. Components and inside walls of the building were contaminated with natural uranium materials. Some parts of the stainless steel pipes and concretes of the walls were sampled and analyzed their alpha and gamma activities respectively. Alpha and gamma activities are well matched each other in the range of high activity region to 0.01 Bq/g and gamma activities are over estimated comparing alpha activities corresponded in below 0.005 Bq/g region for the natural uranium of AUC sample. The $^{238}U$ originated from natural products of conversion process could be distinguished by measuring $^{214}Pb$ or $^{214}Bi$ and $^{234}Th$ or $^{234m}Pa$. Uranium contaminations mainly are in the wall surface of the plant. Decontamination process of generating wastes which can be reached tp background level gamma activities measured by gamma spectroscopy can also be used to conservative assessment data.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.193-200
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• 2014

In this paper, the prototype of one-channel gamma-ray spectroscope for automatic radiopharmaceutical systhesis system was designed and characterized. The prototype employed CZT (CdZnTe) spear detector for gamma-ray detection and employed analog-type signal processing method. A radioactive sample Co-60 was used for measuring performance of the gamma-ray spectroscope and energy spectrum is gained with bandwidth of 1173keV. The analog board is made up of SF (shaping filter) and PHA (peak and hold amplifier) for shaping CZT output signal appropriately and ADC (analog to digital converter) and FPGA (field programmable gate array) for drawing gamma-ray spectrum by counting the digitalized gamma-ray signal data.

• Journal of Radiation Protection and Research
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• v.16 no.2
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• pp.1-6
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• 1991

The $HgI_2$ single crystal which can be used for the ${\gamma}-ray$ detector at room temperature was grown by Temperature Oscillation Method. The low temperature photoluminescence, specific resistivity and trap concentration of $HgI_2$ single crystal were investigated. Three main luminescence bands were observed at 2.30eV, 2.20eV and 2.00eV at 20K, related to the excitons, I-vacancies and impurities, respectively. The specific resistivity and trap concentration of $HgI_2$ single crystal were $10^{11}{\Omega}\;cm\;and\;1.8{\times}10^{14}/cm^3$ at room temperature, respectively. Also the radiation detecting system was deviced by $HgI_2$ ${\gamma}-ray$ detector, one chip microprocessor, LCD module and personal computer. The prepared $HgI_2$ ${\gamma}-ray$ detector showed a good linearity of ${\gamma}-radiation$ dose for standard ${\gamma}-ray$.