‘The following data are abstracted froz experixe:tal results, wherein . a thin P* source prepared by soeking a filter paper in a solution of phosphetes, allowing it te dry, and then measuring surface dose rates with a surfece lonisetion charber.® Thickness of source Activity of source -. _— . - 9.6 ng/ex* | | Surface dose rate 0.127 rep/sec _ 457. Dosage rate at depth of x centinsters ee 77,0pe/oxt reps/hr p7 705K &. Theoretically _ equetion R = Hach (for P32) Substituting above deta wm. e 5)( 0. 007) &9 ne 25 Foe = 7.0 C repa/hr Let C & 77pc/ext Then R@ 77 wee oa)reve/ar ah 7 ng/en? (P32) *Ef ecE t: xternal Zirkle, Rayuond E. FeGrawiill Book os Tp Conupany. 1951. aay -FF= “63