610
106
_
ITT
0.427 - MEV !255h
=
a
_
0.840 - MEV Mn
105
=
=
—
D
z
=
a
sf
—
0.513 - MEV
7
l0sRh
~
T-
yq4
'°
=
0.598 - MEV "25s,
—
=
~
—
<<
x=
|
_
U
a
a
>
Z
0 10%
¥
1.05 - MEV
106Rh,
=
—
a
1.13-MEV "Srp
1.17-MEV ®Co
=
1.33 - MEV Co
T
=
1.69-MEV "45h _]
102
—
2.18-MEV '4p;
=
—
10!
0
=
Lt
40
|
|
80
l
—
120
{
160
l
|
200
CHANNEL NO.
Fig. 35—Gamma spectrum of Star Dust sample high in activation products. Sample collected between 60 to 70°N and 00 to 07°W on Sept. 7,
1962. The 800-min spectrum was taken 13.5 months after collection.
These numbers are even higher than the *°Sb/*Sr ratio from the 14-
Mev neutron fission of 7°U. For example, Broom’® reported a value of
2.5 for this ratio. These data indicate a nonfission origin for most of
the '25Sb in the previously mentioned exceptional samples.
Antimony-125 can be produced by activation through the following
three reactions:
14Sn(n,y)!25Sn
Bo
1259),
1257 e(np)!5gp
23Sb(n, y)4Sbin,y 25S
If tin is activated, ''%Sn should also be produced. The tin fraction was
isolated from several samples and counted, but no ‘Sn could be
detected (activity was less than 3 to 4 dis/min, whereas that of 1225p
in the same samples was between 100 and 10,000 dis/min). No *!Te
could be detected in the same way.