DNA 1240H-2
The dose rate at 3 ft above the sinb over the exposure point may be
expressed by:
nRBe- (ux)!
dap =
dA
We
(r/nr)
(17-34)
h= -3
From inspection of Fqs.17-32,17-33,and 17-34 it is apparent that
dose rate ratios required in Fq.l’-3 to evaluate the shielding factor
have the following equivalences:
per
lin)!
(an) as
RP n(x)’
aa
unxe
fo,
ze tux)
7
?
(17-35)
pte aa
J),
a3n
a
«Re
Be” (ux)" aa
sae
h= -3)
The evaluation of the integrals of Eq. 17-35 for all the energies in the
source spectra would be an extremely lengthy task, even when machinecommited.
Therefore, the actual spectra have been replaced with
pseudospectra, as described in 17.55. f&valuation of the ratios cf
Eq. 17-% has been carried out for the five gamma-ray energies of the
pseudospectra, for various distances below the slab, and for slab
thicknesses of 0 to 10 inches. Results are presented graphically in
Ref. 71.
Note that Ref.71 uses the following symbols:
I, instead of a) 55
Igo
instead of d,
I
instead of dpr
cOPY
E
L
B
A
L
I
A
V
A
BEST
17-84
Sn ee ey cette teen ameaa ee = ee ee we re me re ee re
er ee ee ee
ee ee