[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;

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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;"

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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),

白山羊さんの宿題.PDF

白山羊さんの宿題.PDF ICRU Report 60 Fundamental Quantities and Units for Ionizing Radiation (1998) dosimetric quantity exposurex kermak absorbed dosed 1) fluenceφ hν 1. ρ x Φ/Φ { Φ/Φ}/{ρ x} mass attenuation coefficient µ/ρ