• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2012년도 춘계학술대회 논문집
• /
• pp.863-864
• /
• 2012

• 한국연소학회지
• /
• 제5권1호
• /
• pp.91-98
• /
• 2000

We investigated a uniform temperature zone, produced by double flame structure of a co flow CH4/air partially premixed flame, to be used as a temperature calibration source for laser diagnostics. A broadband N2 CARS(coherent anti-Stokes Raman spectroscopy) system with a modeless laser was used for temperature measurement. When the stoichiometric ratio was 1.5, we found the uniform temperature zone in radial direction of the flame of which the averaged temperature was 2110 K with standard deviation 24 K. In the stoichiometric ratio range between 2.0 and 2.5, we found very stable temperature-varying zones in vertical direction at the center of the flame. The size of the zone was approximately 15 mm and it covered a temperature range from 300 K to 1900 K. We also suggest that this zone can be used as a calibration source for 2-D PLIF(planar laser induced flurescence) temperature measurement.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
• /
• pp.577-580
• /
• 2004

To overcome with large size noise source distribution network design difficulty in interferometric radiometer system, especially for sub-Y-type array, a new on-board calibration technique using noise re-radiation is proposed in this paper. The suggested calibration technique is using noise re-radiation effect of center antenna after noise source injection from matched load. This approach is especially proper to sub-Y-type array interferometric synthetic aperture radiometer in mm-wave frequency band. Compared with noise injection network of a conventional synthetic aperture radiometer, the system mass, volume, and hardware complexity is reduced and cost-effective. Only one internal noise source, matched load, is used for injection using noise re-radiation technique a small set of sub-Y receiver channels is calibrated. Detailed calibration scenario is discussed and simulation results about noise re­radiation effect are presented.

• Nuclear Engineering and Technology
• /
• 제49권1호
• /
• pp.277-284
• /
• 2017

This paper presents the establishment and characterization of a neutron calibration field using a bare $^{252}Cf$ source of low neutron source strength in Vietnam. The characterization of the field in terms of neutron flux spectra and neutron ambient dose equivalent rates were performed by Monte Carlo simulations using the MCNP5 code. The anisotropy effect of the source was also investigated. The neutron ambient dose equivalent rates at three reference distances of 75, 125, and 150 cm from the source were calculated and compared with the measurements using the Aloka TPS-451C neutron survey meters. The discrepancy between the calculated and measured values is found to be about 10%. To separate the scattered and the direct components from the total neutron flux spectra, an in-house shadow cone of 10% borated polyethylene was used. The shielding efficiency of the shadow cone was estimated using the MCNP5 code. The results confirmed that the shielding efficiency of the shadow cone is acceptable.

• 대한방사선치료학회지
• /
• 제16권1호
• /
• pp.21-27
• /
• 2004

목적 : 근접치료에 사용하는 동위원소인 Ir-192는 전량 수입에 의존하고 있으며, 그 Activity는 Welltype Chamber를 이용하여 측정하거나 제조업체의 선원 강도 인증서를 믿고 의존하는 방법, 또는 Farmer Chamber를 이용한 in-air dosimetry 등이 있다. 본 논문에서는 좀더 간단하고 단순한 Farmer Chamber를 이용한 방법을 소개하고자 한다. 대상 및 방법 : Farmer Chamber와 Source Calibration jig를 이용하여 Ir-192 동위원소의 Activity를 측정하고 그 값을 제조사의 선원강도 인증서의 값과 비교하여 선원의 Activity를 check한다. 결과 : 측정결과 제조사의 값과 비교하여 ${\pm}2.1\%$로, AAPM 권고 값인 ${\pm}5\%$ 안의 오차범위에 들어가는 차이로서 임상에서의 사용이 가능하다. 결론 : 근접치료장치의 사용증가와 그에 따른 선원의 수입 증가는 불가결하다. 그리고 선원의 정확한 Activity Check는 필수이다. 선원의 Act check를 위해 Well type chamber의 추가 구입 없이 Farmer Chamber와 Source Calibration jig를 이용하여 정확한 선량 측정이 가능하였다.

• 설비공학논문집
• /
• 제10권6호
• /
• pp.795-802
• /
• 1998

For measuring the thermal diffusivity by laser flash method, raw data have to be calibrated using temperature data. We have developed in-process calibration method and polynomial calibration in which thermal diffusivity can be calibrated during measuring, This method is different from existing temperature pre-process calibration method and exponential calibration having various source of error. Using this new calibration method, measurement accuracy was improved about 1∼2% compare to the value by the existing method. We also studied more accurate fitting curve as in Figure 4 was shown the result of measuring output characteristics of IR radiometer with temperature. As illustrated in data, in-process calibration method and polynomial calibration equation is proper than pre-process calibration method and exponential calibration.

• 한국의학물리학회:학술대회논문집
• /
• 한국의학물리학회 2002년도 Proceedings
• /
• pp.23-27
• /
• 2002

Two $^{192}$ Ir HDR brachytherapy sources were calibrated with a Farmer ionization chamber in air method and in a PMMA cylindrical phantom. The calibration air method used ionization chamber with buildup cap, and 8 variation distances for center-to-center of the source to chamber. In the optimum distance the measured activity, especially for the high activity source, deviation was 0.3% from the activity provided by manufacturer. Calibration with a PMMA cylindrical phantom was less sensitive, and suitable for quick check method with accuracy less than 10%.

• 한국농공학회논문집
• /
• 제55권1호
• /
• pp.17-29
• /
• 2013

Long-Term Hydrologic Impact Assessment (L-THIA) model which is a distributed watershed model was applied to analyze the spatial distribution of surface runoff and nonpoint source pollutant loading from Imha watershed during 2001~2010. L-THIA CN Calibration Tool linked with SCE-UA was developed to calibrate surface runoff automatically. Calibration (2001~2005) and validation (2006~2010) of monthly surface runoff were represented as 'very good' model performance showing 0.91 for calibration and 0.89 for validation as Nash-Sutcliffe (NS) values. Average annual surface runoff from Imha watershed was 218.4 mm and Banbyun subwatershed was much more than other watersheds due to poor hydrologic condition. Average annual nonpoint source pollutant loading from Imha wateshed were 2,295 ton/year for $BOD_5$, 14,752 ton/year for SS, 358 ton/year for T-N, and 79 ton/year for T-P. Amount of pollutant loading and pollutant loading rates from Banbyun watershed were much higher than other watersheds. As results of analysis of loading rate from grid size ($30m{\times}30m$), most of high 10 % of loading rate were generated from upland. Therefore, major hot spot area to manage nonpoint source pollution in Imha watershed is the combination of upland and Banbyun subwatershed. L-THIA model is easy to use and prepare input file and useful tool to manage nonpoint source pollution at screening level.

• Nuclear Engineering and Technology
• /
• 제51권2호
• /
• pp.526-532
• /
• 2019

In this study, an in-house $^{152}Eu$ calibration source was produced from a custom epoxy matrix with a density of ${\rho}=1.14g\;cm^{-3}$, which is chemically stable and durable form after its solidification. The homogeneity of $^{152}Eu$ in matrix was obtained better than 98%. For a Marinelli beaker geometry, an efficiency calibration procedure was applied to a n-type, coaxial, 78.5% relative efficient HPGe detector in the energy range of 121.7-1408.0 keV by using in-house $^{152}Eu$ calibration source. Then the measured efficiencies for Marinelli geometry were compared with the results calculated by MEFFTRAN and ANGLE softwares for the validation. Although MEFFTRAN and ANGLE have two different efficiency transfer algorithms to calculate the efficiencies, they usually need to use a reliable and accurate reference efficiency values as input data. Hence, reference efficiency values were obtained experimentally from a multinuclide standard source for the same detector-Marinelli geometry. In the present source characterization, the corrections required for self-absorption and true coincidence summing effects for $^{152}Eu$ gamma-rays were also obtained for a such close counting geometry condition. The experimental results confirmed the validity of efficiency calculations obtained by MEFFTRAN and ANGLE softwares that are calculation tools.

• Radiation Oncology Journal
• /
• 제13권1호
• /
• pp.101-104
• /
• 1995

High Dose Rate Remote Afterloading system was installed at Wonkwang University Hospital in January 1994. In this report, the calibration of a Gammamed 12-i High Dose Rate Remote Afterloading system and the radiation survey around the facility after design and construct a shieding room are discussed. The radiation survey of the facility indicates that the use of ordinary concrete shielding of existing room will provide adequate shielding. Also, the methodologies for performing source calibration are presented.