
470 Nuclear Forensic Analysis
Th sample, obtained with a Si surface-barrier detector. The spectrum obtained for
t
he
D
EA
s
ample
i
s
s
hown
i
n
F
igure
2
5.2.
M
ost
o
f
t
he
n
uclear
f
orensic
i
nformation
d
etermined
f
rom
t
his
s
ample
a
rose
f
rom
a
n
i
nterpretation
o
f
t
he
d
ata
p
resented
i
n
t
his
gure.
In
F
igure
2
5.2,
t
he
p
eak
r
esulting
f
rom
d
ecay
o
f
3
.66-day
224
Ra derives from its
i
ngrowth
f
rom
228
Th decay between the time the Th fraction was puried and the
t
ime
t
he
s
pectrum
w
as
a
cquired.
T
he
d
ecay
d
aughters
o
f
224
Ra (55-s
220
Rn, 145-ms
216
Po, etc.) were also observed at higher energies, but are not shown in the gure. At
l
ower
e
nergies,
o
nly
t
he
i
sotopes