The following data are abstracted from ex,¢ericental results, wherein
a thin paz souree prepared by soaking a filter payer in a solution of
phosphates, allowing it to dry, and then weasuring surface dose rates
with a surface ionization chanber.®
Thickness of source
9.6 ng/ex*
Activity of source
7740pale
Surface dose rate
.
0.127 rep/see
457
Dorage rute at depth of x centimeters
ie
repe/hr
‘
oF «5x
~
Zheoret ically
R = sos (for ¥32)
Subst ituling abowe dates
nw
Re
95 Noe72-5) (9.007) | go
DOL /ty
2
= 7,0 C repe/br
let C® 77po/ex*
Then Rk» 7 x 77
a“
= $39 repa/br at 7 ag/er® (17°)
“nifecE
is
xteral Zirkle, Raymond X. MeGrawiiill Book
Company,
1951.
(4