Air Density Correction of Ionization Chamber using $^{90}Sr$ Radioactive Check Device

$^{90}Sr$ 방사성 동위원소를 이용한 전리함의 대기 보정계수 측정

  • Park, Sung-Y. (Department of Radiation Oncology, Inha University) ;
  • Kim, Woo-C. (Department of Radiation Oncology, Inha University) ;
  • Shin, Dong-O. (Department of Physics, Kyonggi University) ;
  • Ji, Young-H. (Department of Physics, Kyonggi University) ;
  • Kwon, Soo-I. (Department of Physics, Kyonggi University) ;
  • Lee, Kil-D. (Department of Physics, Kyonggi University) ;
  • Cho, Young-K. (Department of Radiation Oncology, Inha University) ;
  • Loh, John-J. (Department of Radiation Oncology, Inha University)
  • 박성용 (인하대학교 의과대학 방사선종양학교실) ;
  • 김우철 (인하대학교 의과대학 방사선종양학교실) ;
  • 신동오 (경기대학교 이과대학 물리학과) ;
  • 지영훈 (경기대학교 이과대학 물리학과) ;
  • 권수일 (경기대학교 이과대학 물리학과) ;
  • 이길동 (경기대학교 이과대학 물리학과) ;
  • 조영갑 (인하대학교 의과대학 방사선종양학교실) ;
  • 노준규 (인하대학교 의과대학 방사선종양학교실)
  • Published : 1998.12.30

Abstract

It is required to measure air density correction factor at the time of absorbed dose calibration or measurement. In general, thermometer and barometer are widely used for air density correction. However, this can be done using the radioactive check device with better accuracy. The measurements of air density correction were performed by using the radioactive check device, Unidos electrometer, and 0.6 cc Farmer-type ion chamber of PTW under the different environmental conditions. Above experiments were repeated with thermometer and barometer. By comparing the two methods, they were within the difference of 0.2 %. The overall uncertainty for the dose found in thermometer and barometer was 1.2 - 1.6 %, depending upon either one step or two, whereas the overall uncertainty for the radioactive check device was 1.02 %. This method may reduce the possible error which could occur when thermometer and barometer are not calibrated at regular basis.