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球形石墨空腔电离室壁修正因子的测量与验证 被引量:5

Measurement and verification of wall correction factor for the spherical graphite cavity chamber
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摘要 Objective To discuss the method how to identify wall correction factor (K_ wall ). Methods The paper introduce how to use extrapolation of the ionization current measured for different wall thickness by the spherical graphite cavity chamber whose volume is 10 cm3 and 30 cm3 for 60 Co γ-rays. The wall correction factors were determined by this method and Monte Carlo(MC) calculations. Results The results of the present experiment and calculation indicated that the wall correction factor determined by traditional geometry thickness extrapolation method was 1.0% less than that by MC calculation.The result of applying the equivalent mean thickness to calculate with extrapolation method and that of MC calculation were accordable within 0.45%.The relative dose and wall correction factors for the spherical graphite cavity chamber whose volume is 30 cm3 and 50 cm3 of the standards of air kerma of the NIST for 60 Co γ-rays were calculated by MC calculation,and the calculation results were in accordance with the published values of NIST within 0.06%. Conclusion The spherical graphite cavity chamber wall correction factor determined by traditional extrapolation method and MC calculation is accordable with the results of foreign labs (PSDL).; Objective To discuss the method how to identify wall correction factor ( Kwall ) . Methods The paper introduce how to use extrapolation of the ionization current measured for different wall thickness by the spherical graphite cavity chamber whose volume is 10 cm^3 and 30 cm^3 for ^6o Co γ-rays. The wall correction factors were determined by this method and Monte Carlo (MC) calculations. Results The results of the present experiment and calculation indicated that the wall correction factor determined by traditional geometry thickness extrapolation method was 1.0% less than that by MC calculation, The result of applying the equivalent mean thickness to calculate with extrapolation method and that of MC calculation were accordable within 0.45 % , The relative dose and wall correction factors for the spherical graphite cavity chamber whose volume is 30 cm^3 and 50 cm^3 of the standards of air kerma of the NIST for ^6o Co γ-rays were calculated by MC calculation, and the calculation results were in accordance with the published values of NIST within 0.06%. Conclusion The spherical graphite cavity chamber wall correction factor determined by traditional extrapolation method and MC calculation is accordable with the results of foreign labs (PSDL) .
出处 《中华放射医学与防护杂志》 CAS CSCD 北大核心 2005年第6期561-564,共4页 Chinese Journal of Radiological Medicine and Protection
基金 国家自然科学基金资助项目(10275058)
关键词 空腔电离室 空气比释动能 壁修正因子Kwall 蒙特卡罗模拟 Cavity chamber Air kerma Wall correction factor (Kwall) Monte Carlo calculations
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参考文献10

  • 1Rogers DWO,Bielajew AF.Wall attenuation and scatter corrections for ion chambers:measurements versus calculations.Phys Med Biol,1990,35:1065-1078.
  • 2Rogers DWO,Bielajew AF,Nahum AE.Ion chamber response and Awall correction factors in a ^60 Co beam by Monte Carlo simulation.Phys Med Biol,1985,30:429-443.
  • 3Bielajew AF.Correction factors for thick-walled ionization chambers in point-source photon beams.Phys Med Biol,1990,35:501-516.
  • 4Bielajew AF.On the technique of extrapolation to obtain wall correction factors for ion chambers irradiated by photon beams.Med Phys,1990,17:583-587.
  • 5Bielajew AF,Rogers DWO.Implications of new correction factors on primary air kerma standards in ^60Co beams.Phys Med Biol,1992,37:1283-1291.
  • 6Rogers DWO,Treurniet J.Monte carlo calculated wall and axial nonuniformity corrections for primary standards of air kerma.NRCC Report PIRS-663,1999.
  • 7Laitano RF,Toni MP,Pimpinella M,et al.Determination of the Kwall correction factor for a cylindrical ionization chamber to measure air-kerma in ^60Co Gamma Beams.Phys Med Biol,2002,47:2411-2431.
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同被引文献37

  • 1胡家成,杨小元,杨元第,张辉,樊铁栓,孙吉宁,黄斐增,刘鉴常,叶卫国.球-圆柱形空腔电离室壁修正因子的实验测量[J].计量学报,2007,28(z1):256-260. 被引量:2
  • 2李震,马铁军.医用诊断X射线辐射源测量结果的不确定度分析[J].生物医学工程研究,2012,31(1):61-64. 被引量:6
  • 3韩奎初.测量照射量(空气比释动能)的空腔电离室[J].核标准计量与质量,1995,0(1):33-35. 被引量:3
  • 4田中青.空气比释动能与照射量比较[J].现代测量与实验室管理,2004,12(3):21-23. 被引量:3
  • 5[1]Rogers D W O,Bielajew A F.Wall attenuation and scatter corrections for ion chambers:measurements versus ealculations[J].Phys Med Biol,1990,35:1065~1078.
  • 6[2]Rogers D W O,Bielajew A F,Nahum A E.Ion Chamber Response and Awall Correction Factors in a 60Co Beam by Monte Carlo Simulation[J].Phys Med Biol,1985,30:429~443.
  • 7[3]Bielajew A F.Correction Factors for Thick-walled Ionization Chambers in Point-source Photon Beams[J].Phys Med Biol,1990,35:501~516.
  • 8[4]Bielajew A F.On the Technique of Extrapolation to Obtain Wall Correction Factors for Ion Chambers Irradiated by Photon Beams[J].Med Phys,1990,17:583~587.
  • 9[5]Bielajew A F,Rogers D W O.Implications of New Correction Factors on Prinary Air Kerma Standards in 60Co Beams[J].Phys Med Biol,1992,37:1283~1291.
  • 10[6]Rogers D W O,Treurniet J.Monte Carlo Calculated Wall and Axial Non-uniformity Corrections for Primary Standards of Air Kerma[R].NRC,Report PIRS-663,1999.

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