Radioactivity and radiation protection

32

RADIOACTIVITY AND RADIATION PROTECTION Unit of activity = Curie: t Ci = 3 , 7 X t 0 t0 d i s i n t e g r a t i o n s / s e c Unit of e x p o s u r e dose for x a n d y radiation = Roentgen: I R = I e s u / c m 3 = 87.8 erg/g ( 5 . 4 9 × 1 0 7 M e V y g ) of air

Unit of a b s o r b e d dose = rad: 1 rad = t00 e r g / g (6.25Xt0 7 MeV/g) in any m a t e r i a l Unit of dose equivalent (for protection) = rem: reins (Roentgen equivalents for m a n ) = rads X O F , w h e r e Q F (quality factor) d e p e n d s u p o n the type of radiation and other factors. F o r ¥ rays and H E protons, Q F = i; for t h e r m a l neutrons, Q F = 3; for fast neutrons, Q F ranges u p to 10; a n d for a particles a n d h e a v y ions, Q F ranges u p to 20.

M a x i m u m p e r m i s s i b l e occupational dose for the whole body: 5 r e m / y e a r (or ~ t00 m i l l i r e m / w e e k )

Fluxes (per cm2) to liberate iR in carbon: 3X i07 m i n i m u m ionizing singly charged p a r t i c l e s 0.9X i09 protons of t MeV energy ( T h e s e fluxes are correct to within a factor of 2 for all materials. )

Natural background: cosmic

i20 to t30 m i l l i r e m / y e a r

,,~

radiation (charged particles + neut .... ) ~ 2 5 ~

~ 25 }

c o s m i c radiation (y rays) radiation f r o m rocks a n d air (y rays) C o s m i c r a y b a c k g r o u n d in counters: ~

~ 73~

I/min/cm2/ster

PERIODIC TABLE OF THE ELEMENTS

VIIA

2 He 4.0026

6 7 8 9 C N F O 12.011 14.0067 15.9994 ! 8.9984

l0 Ne 20.17

1

H 1.008

IA

IIA

3 Li 6.94

4

5

Be

B

IliA

9.0122

10.81

11 12 Na Mg 22.9898 24.305 IIIB 21 19 20 Sc K Ca 39.102 40.08 44.956 37 Rb 85.47

38 Sr 87.62

IVB

22 Ti 47.90

39 40 Y Zr 88.906 91.22

VB

VIB

41 Nb 92.906

i ~ [ Ce 58 ' Pr 59 I N~ 138.91 140.12 140.9~ 144.24

I "(227) Ac

90

,

: - -

VIII

----~

42 Me 95.94

,2

76 Os i 90.2

77 Ir 192.2

VIA

15 16 P S 30.9738 32.06

17 CI 35.453

18 A 39.948

33 34 As Se 74.9216 78.96

35 Br 79.904

36 Kr 83.80

liB

29 Cu 63.55

30 Zn 65.37

31 Ga 69.72

32 Ge 72.59

47

48 Cd 112.40

49 In 1! 4.82

50 51 53 52 54 Sn Sb Te I Xe 118.69 1121.75 127.60 126.9045 131.30

78 79 80 Pt Au Hg 195.09 196.967 200.59

81 Tl 204.37

82 Pb 207.2

43 44 45 46 Tc Ru Rh Pd 98.9062 101.07 J 102.905 106.4 75 Re 186.2

14 Si 26.981 .~ 28.086

VA

IB

23 24 25 26 27 28 V Cr Fe Mn Co Ni 50.941 51.996 54.9380 55.847 58.9332 58.71

57-71 72 73 74 55 56 Rare Hf W Cs Ba Ta 132.905 : 137.34 Earths 178.49 180.947 183.85

I

VIIB

IVA

83 84 Bi Po 208.981 (209)

85 At (210)

61 [ Sm 62 I Eu 63 I G6~ I Tb 65 I Dy 66 [16~7930 68 I Tm 69 I Yb 70 [ Lu 71 [ Pm He Er (145) 150.4 151.96 157.25 158.925 162.50 167.26 168.934 173.04 174.97

,,

Tb Pa U I Np Pu 232.038 231.036 238.03 1237.048 (244)

Am (243)

Cm (247)

Bk (247)

Cf (251)

Es (254)

Fm (257)

f (256) 01021 Md No (254)

(260)

Numbers in parentheses are mass numbers of most stable isotope of that element. Adapted from the

Handbook o f Chemistry and Physics, 1973-74. (Particle Data Group update, April 1974.)

[

86 Rn (222)

Rare earths (Lanthanide series)

Actinide series