21000
5,550
jon
700
5
>
om &
>
e
“a
>
T
oc
2.62 MEV
Tl208
me
te a neoe ae
5 MEV.
9
Dose rate (yr./h)
re
ies)
ries}
35,000
18,q00
>
>
+
Uniform
'
”
”
‘t
>
>
Peak counts/pr./h
6,000
co
1
l
Source
Exponential
Tl
%”
>
B CALIBRATION OF SPECTROMETER
|
;
!
120 140 160 180 200 220 240 260
anne! No.
. obtained during late 1962, Top curve :
er 11, 1962; bottom curve: Argonne,
mic ray, natural and fall-out levels are
‘the Colorado Springs location
tal y-dose rate, as moasured by
zation chamber, and the natural
d by the peak or energy-band
10d involves the determination
0-75-MeVtotal absorption peaks
4
I
i
|
I
I
L
!
!
!
May June July Aug. Sept. Oet. Nov. Dee. Jan. Feb.
Date of mensurement (1963-64)
Fig. 2. Fall-out y-dose rates at three locations in Westchester Co., N.Y.
(4, Mamaroneck ; 8, West Harrison; (', Pelhum.) The triangles refer
to spectrometer readings and the circles to readings with the ionization
chamber only
in @ manner analogous to that for the higher energy peaks
characteristic of the natural emitters. These areas can
also be related to the incoming primary flux in thefield
situation and thus to the total dose rate from the contributing isotopes.