[2] ATMUKN [3] (ATMU ATMUKN)[4] ( ) X tr = f photo photo + f incoh incoh + f pair pair = E h 0 (2) h 0 E 1 f photo =1; X h 0 f incoh f pair =1;

Size: px

Start display at page:

Download "[2] ATMUKN [3] (ATMU ATMUKN)[4] ( ) X tr = f photo photo + f incoh incoh + f pair pair = E h 0 (2) h 0 E 1 f photo =1; X h 0 f incoh f pair =1;"

あまめひろなが
5 years ago
Views:

1 ICRP90 (AP ) ICRP (photoelectric eect) (coherent scattering) (incoherent scattering) ( (pair creation) (triplet creation)) = photo + coh + incoh + pair (cm ;1 ) (1) (linear attenuation coecient) (mass attenuation coecient, m (cm 2 =g), ATMU) m N 0 (t cm) ( ) N 0 exp(;t) (Buildup Factor) (ATMUKN) ANS-6.4.3[1] 1

2 [2] ATMUKN [3] (ATMU ATMUKN)[4] ( ) X tr = f photo photo + f incoh incoh + f pair pair = E h 0 (2) h 0 E 1 f photo =1; X h 0 f incoh f pair =1; <h>+x h 0 =1; 2mec2 h 0 =1; 2mec2 +X h 0 for pair creation for triplet creation X: 1 X <h>: m e c 2 : X KX- X X 1993 Seltzer [5] 1961 Berger [6] Al Fe X Hubbell 1969 [7] 18 K Higgins NIST [8] Hubbell [5] [13] [9] 2 9 >= > (3)

3 K = E tr m : (4) E tr m (Gy=J/kg) (2) ( tr = cm 2 /g) (h 0 MeV/cm 2 ) K = tr = h 0 (MeV=g) = 1: ;10 tr = h 0 (Gy) (5) ICRP 74[10] (Table A.1) ICRU- 47[11] 1982 Hubbell [12] ( ) Seltzer g ( X Private communication Table A.1 1-g ) (Table A.21) 1995 Hubbell [13] g K a = 1995 Hubbell ( ) ICRP Hubbell ICRU 47Table A.1 1 ; g Higgins [8] 2.3 X X (collision loss) X (radiation loss) (E c ) " c = 800 (MeV) (6) Z +1:2 [14] X ( X g) en en = tr (1 ; g) (7) g X Hubbell [6, 15, 7, 16, 12, 8, 13] [13] NIST ( Physics and Reference Data) 3

4 Hubbell Higgins g 1 1 MeV Habbell 1.04 Ratio to µ (Hubbell ) en µ tr (Hubbell-1982) µ en (Hubbell -1982) µ tr (Higgins ) Photon Energy (MeV) 1: (Hubbell en (1995 ) ) (collision kerma) K C = en = h 0 (MeV=g) = 1: ;10 en = h 0 (Gy) (8) D = E m (9) E m 4

5 \ " D = K C = 1: ;10 en = h 0 (Gy) (10) Carlsson [17] 1 MeV g =0 10MeV 4% 2.4 1cm X = Q (11) m Q m X = e W (1 ; g)k = e W K C: (12) W J/C(=33.97 ev/e) [11] C=kg (R) 0 C 1 1cm 3 ( g) 1esu 1R = 2:58 10 ;4 C/kg W ICRU 47 Table A.1 \The exposure, X, is not accurately determined at energies above 3 MeV since there is signicant departure from electronic equilibrium." 3 MeV 5

6 1 1 ; g[11] [12, 13] Energy m m tr = 1 1 ; g[11] en =[12] tr =[8] en =[13] ATMU ATMUKN (MeV) (cm 2 /g) (cm 2 /g) (cm 2 /g) (cm 2 /g) (cm 2 /g) (cm 2 /g) Hubbell 1982 ICRU 47Table A.1 1 ; g 6

7 [18] X 2 [18] Primary Secondary Secondary Charged Energy Energy Particle Energy (E E ) c (E L ) c (E E ) u (E L ) u (E R ) u e ; e P (E E ) c : (E L ) c : (E E ) u : (E L ) u : (E R ) u : (E E ) c ; (E L ) c =1:4 ; 1:4 =0 K =0:5+0:5+0:5+0:5+1: :978 = 5:956 (MeV) (13) E E = (E E ) c ; (E L ) c +(E E ) u ; (E L ) u ; (E R ) u = 1:4 ; 1:4+10:0 ; 3:022 ; 1:022 = 5:956 (MeV) (14) X 3 X (E E ) c =(E L ) c =0 E tr > E X K C = D 7

8 Photoelectric effect Compton Scattering 6 7 Pair creation : ( )[18] 3: D 6= K [18] 6 MeV Al Al 4 EGS4[19] [7] [13] 1mm 1mm 5 1mm Al Al 1cm 5 8

9 Kerma Collision Kerma Absorbed Dose cm 2 MeV g Depth in Al (cm) 4: 6 MeV Al (E E ) C -(E L ) C (MeV cm 2 /g) MeV photon (E E ) C -(E L ) C (MeV cm 2 /g) MeV photon Depth in Al (cm) Depth in Al (cm) 5: 1mm ((E E ) C ) ((E L ) C ) 4 9

10 W W 100keV 3 [20] 5 MeV 2.5cm MeV 3 [20] (MeV) a (g cm ;2 ) a 5 (AP) 2 (AP) ICRP90 ( ) (AP) Hubbell[12] Seltzer g ICRP 74[10] Table A.1 ( cm ;2 ) (AP) 4 4 en =[13] (K C, ) (X, R) (AP) 6 ICRP (5), (8) (11) 10

11 ICRP 74 4 ICRP 47 11

12 4 (AP) Energy K 1 2 KC 3 X 3 MeV SvGy ;1 psvcm 2 SvGy ;1 msvr ; tr = 4 2 ICRU Report 47[11] Table A en =[13] 12

13 [1] Prepared byd.k.trubey, \New Gamma-Ray Buildup Factor Data for Point Kernel Calculations: ANS Standard Reference Data", NEUREG/CR-5740, ORNL/RSIC-49/RI(1991). [2] H. Hirayama and D. K. Trubey, \Eects of Incoherent and Coherent Scattering on the Exposure Buildup Factors of Low-Energy Gamma Rays", Nucl. Sci. Eng. 99(1988) [3] Y. Namito, S. Ban and H. Hirayama, \Eects of Linear Polarization and Doppler Broadening on the Exposure Buildup Factors of Low-Energy Gamma Rays", Nucl. Sci. Eng. 120(1995) [4] \Photon Interaction Cross Section Library", Radiation Shielding Information Center Data Package DLC-136/PHOTX, National Institute of Standards and Technology. [5] S. M. Seltzer, \Calculation of Photon Mass Energy-Transfer and Mass Energy-Absorption Coef- cients", Rad. Res. 136 (1993) [6] R. T. Berger, \The X- or Gamma-Ray Energy Absorption or Energy Transfer Coecient: Tabulation and Discussion", Rad. Res. 15(1961)1-29. [7] J. H. Hubbell, \Photon Cross Sections, Attenuation Coecients, and Energy Absorption Coecients from 10 kev to 100 GeV, NSRDS-NBS 29 (1969). [8] P. D. Higgins, F. H. Attix, J. H. Hubbell, S. M. Seltzer, M. J. Berger and C. H. Sibata, \Mass Energy-Transfer and Mass Energy-Absorption Coecients, Including In-Flight Positron Annihilation for Photon Energies 1 kev to 100 MeV, NISTIR 4812(1992). [9] Private communication. [10] ICRP Publication 74,\Conversion Coecients for use in Radiological Protection against External Radiation", Annals of ICRP 26, No.3/4(1996). [11] ICRU Report 47, \Measurement of Dose Equivalents from External Photon and Electron Radiations", 15 April [12] J. H. Hubbell,\Photon mass attenuation and energy absorption coecients from 1 kev to 20 MeV", Int. J. Appl. Radiat. Isot. 33(1982) [13] J. H. Hubbell and S. M. Seltzer, \Tables of X-Ray Mass Attenuation Coecients and Mass Energy-Absorption Coecients 1 kev to 20 MeV for Elements Z=1 to 92 and 48 Additional Substances of Dosimetric Interest", NSTIR 5632, (1995). [14] M. J. Berger and S. M. Seltzer, \Tables of Energy Losses and Ranges of Electrons and Positrons", NASA-SP-3012, National Aeronautics and Space Administration (1964). [15] J. H. Hubbell and M. J. Berger,\Sec. 4.1: Attenuation Coecients, Energy Absorption Coef- cients, and Related Quantities", in Engineering Compendium on Radiation Shielding, Vol. 1, R. G. Jaeger, ed. (Springer, Berlin), (1968). [16] J. H. Hubbell, \Photon Mass Attenuation and Mass Energy-Absorption Coecients for H, C, N, O, Ar, and Seven Mixtures from 0.1 kev to 20 MeV", Rad. Res. 70(1977)

14 [17] G. A. Charlsson, \Theoretical Basis for Dosimetry", in The Dosimetry of Ionizing Radiation, Vol. 1, pp.1-75, Academic Press, INC. (1985). [18] K. R. Kase, W. R. Nelson, \Concepts of Radiation Dosimetry", SLAC-153, Stanford Linear Accelerator Center (1972) ibid. Pergamon Press, New York(1978). [19] W. R. Nelson, H. Hirayama and D. W. O.Rogers, \The EGS4 Code System", SLAC-265, Stanford Linear Accelerator Center (1985). [20] G. F. Knoll, \Radiation Detection and Measurements", (John Wiley & Son),

日本保健物理学会専門研究会報告書シリーズ ISSN Vol.5, No.1, 放射線防護に用いる線量概念の専門研究会 2007 年 8 月発行者日本保健物理学会企画委員会発行所日本保健物理学会東京都新宿区西新宿 NPO 事務センター内日本

日本保健物理学会専門研究会報告書シリーズ ISSN Vol.5, No.1, 放射線防護に用いる線量概念の専門研究会 2007 年 8 月発行者日本保健物理学会企画委員会発行所日本保健物理学会東京都新宿区西新宿 NPO 事務センター内日本 ISSN 1881-7297 日本保健物理学会専門研究会報告書シリーズ Vol.5 No.1 放射線防護に用いる線量概念の専門研究会 2007 年 8 月日本保健物理学会日本保健物理学会専門研究会報告書シリーズ ISSN 1881-7297 Vol.5, No.1, 放射線防護に用いる線量概念の専門研究会 2007 年 8 月発行者日本保健物理学会企画委員会発行所日本保健物理学会 160-0023