• Progress in Medical Physics
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• v.11 no.2
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• pp.123-130
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• 2000

The performance of an electrometer directly affects on the accuracy and precision in radiation dosimetry. This study is to list of the quality control for maintaining performance and to perform evaluation tests of an electrometer. Performance tests selected include proper polarizing voltages, warm-up and equalization time, leakages, long-term stability, linearity, and effect of ambient conditions. An electrometer connected with a rigid stem ionization chamber was evaluated with a Strontium-90 check device. Bias voltage was measured directly on the input socket. Equalization time is the time required for reaching threshold of charged state after the power is on or the bias voltage is changed. Pre- and post-signal leakages are defined as the accumulation of signal with no exposure and after exposure, respectively. Over three months period, the electrometer's long-term stability was measured by comparison of the temperature-pressure corrected readings. Linearity was expressed as the deviation of readings from multiple short exposures from one continuous exposure. Effect of ambient conditions was expressed as the zero drift of the electrometer over 17-34$^{\circ}C$ temperature ranges. For two nominal values, 300 and 500 volts, measured voltages were lower by 2.5 and 5.8%, respectively. The warm-up time, 20 minutes, was longer than the lamp time by 9 minutes and the equalization time was less than 1 minute. Without exposure, the zero-drift was 0.002 scale-unit in 15 minutes and the leakage after 10 minutes exposure was minimal. The IQ-4 was stable over 99.4% for three-month periods. Deviation from the linearity was 0.9% for measurement scale, 0.000-9.991. Over 17-34$^{\circ}C$ temperature range, the zero-drift was minimal, less than 0.2%. For a clinically-used electrometer, a list for the basic peformance evaluations is proposed. By running this program, the measurement error using an electrometer can be reduced and in turn the improvement in accuracy and precision of radiation dosimetry can be achieved.

• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.277-284
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• 1998

To establish the calibration system of hot cathode ionization gauges as transfer gauges, researches were concentrated on measurements of the pressure ratio, the orifice conductance as well as the porous plug conductance of a ultrahigh vacuum standards system. Two ionization gauges obtained from two different vendors were calibrated in the pressure range of $7{times}10^{-7}$ to $4{times}10^{-3}$ Pa by injecting argon gas into the standards system. As a result, a 4% difference was revealed in non-linearity of the extractor ionization gauge due to the pressure difference between high vacuum and ultrahigh vacuum, and 3% for the stabil ionization gauge. It has been understood that the extractor ionization gauge is able to be used within the 10% error, the uncertainty of the extractor ionization gauge, if properly regulating the sensitivity of the gas. The stabil ionization gauge was also proved to be useable in the maximum error margin of 4% without the control of the gas sensitivity.

• Radioisotope journal
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• v.20 no.2
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• pp.6-8
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• 2005

• Progress in Medical Physics
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• v.7 no.2
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• pp.29-40
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• 1996

We had designed and made the cylindrical ionization chamber which operated above 5 mR/h. Using commercial electrometer, we investigated the characterictic of charge collection in the ion chamber. The active volume was 190.4㎤ and overall length and diameter in the chamber was 15.5cm, 5.22cm, respectively. The chamber had three electrodes(inner, central, wall electrode). And background current was 8.39${\times}$10$\^$-14/${\pm}$1.5${\times}$10$\^$-15/A to arrange the electrodes which were coaxial in chamber axis. The collection efficiency of chamber for Cs$\^$137/ was 99.7％ when the opreating voltage was applied 400V. Comparing with the commertial dosimetry system, the exposure calibration constant was 4.531${\times}$19$\^$7/R/C. By normalizing to CS$\_$137/ the relative energy response of the chamber was 1.30 for Am$\_$24/, 1.05 for C0$\_$60/, respectively. When the irrarition tranversed to the chamber axis, the isotropic effect of the chamber was not considerable.

• The monthly packaging world
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• s.137
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• pp.88-93
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• 2004

• Environmental engineer
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• s.66
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• pp.9-13
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• 1992

제2차 대전 이후에는 원자력의 개발로 원자로에서 방사성동위원소를 만들어내개 되었으며 이것이 급격하게 여러 산업분야에 진출하고 있다. 방사성 동위원소의 이용은 매우 광범하게 액면계, 적설계, 지하검층계, 정전기제거기, 특수방전관, 야광도료, 품질개선, 살균보전, 비파괴검사 등에 이용되고 있고 또 추적자로서 광공업, 농수산업, 의료에 사용된다.

• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.146-147
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• 2011

• The monthly packaging world
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• s.132
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• pp.88-93
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• 2004

• Journal of Space Technology and Applications
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• v.1 no.2
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• pp.199-216
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• 2021

In 2020, the solar and space environment division at the Korea Space Science Society surveyed the status of data archives in solar physics, magnetosphere, and ionosphere/upper atmosphere in Korea to promote broader utilization of the data and research collaboration. The survey includes ground- and satellite-based instruments and developing models by research institutes and universities in Korea. Based on the survey results, this study reports the status of the ground-based instruments, data products in the ionosphere and upper atmosphere, and documentation of them. The ground-based instruments operated by the Korea Polar Research Institute and Korea Astronomy and Space Science Institute include ionosonde, Fabry-Perot interferometer in Arctic Dasan stations, Antarctic King Sejong/Jang Bogo stations, and an all-sky camera, VHF radar in Korea. We also provide information on total electron content and scintillation observations derived from the Global Navigation Satellite System (GNSS) station networks in Korea. All data are available via the webpage, FTP, or by request. Information on ionospheric data and models is available at http://ksss.or.kr. We hope that this report will increase data accessibility and encourage the research community to engage in the establishment of a new Space Science Data Ecosystem, which supports archiving, searching, analyzing, and sharing the data with diverse communities, including educators, industries, and the public as wells as the research scientist.

• Journal of the Korean Society of Radiology
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• v.11 no.1
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• pp.37-42
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• 2017

We measured the absorbed dose and the area dose using an ionization chamber type of area dose product (DAP) meter and measured the calibration factor in the X-ray examination. In the indirect dose measurement method, the detector was installed in the radiation part of the X-ray equipment, and the measured value was calculated as the dose at the exposure part. The instrument used to calculate the calibration factor was an X-ray equipment (DK-550R / F, DongKang Medical Co., Ltd., Seoul, Korea). The calibration method for the calibration factor was to connect the DAP meter (PD-8100, Toreck Co. Ltd., Japan) to the calibration dosimeter tube voltage of 70 kV, tube current of 500 mA, 0.158 sec. The reference dosimeter used a semiconductor (DOSIMAX plus A, Scanditronix, $Wellh{\ddot{o}}fer$, Germany). After installing the DAP meter on the front of the multi-collimator of the ionization chamber, the calibration factor of the dosimeter was obtained using the reference dosimeter for accurate dose measurement. Experimental exposure values and values from the calibration dosimeter were calculated by multiplying each calibration factor. The calibration factor was calculated as 1.045. In order to calculate the calibration coefficient according to the tube voltage in the ionization type DAP dosimeter, the absorbed dose and the area dose were calculated and the calibration factor was calculated. The corrective area dose was calculated by calculating the calibration factor of the DAP meter.