Til
50} 137.5 — 137.5 > 87. ae
37.5al
©
COUNTS / MINUTE (RELATIVE)
Ol
>
hm
CALCULATED BACKGROUND
©
arAke
Yo
oO
LS81a0s
°
1lOr
°0
Oo
lOO
200
Jo
500
300 _ | 400
|
600
2 (om?)
491 Rev.DC
|“Fig. eTeR:Stevenson
and
Authors:
!
| a
P.C.
H.C. Hicks