
80 Nuclear Forensic Analysis
occurs long before the fragments have receded a sufcient distance from one another
t
o
b
e
o
bserved,
s
o
t
he
l
aw
o
f
c
onservation
o
f
m
omentum
d
oes
n
ot
s
trictly
a
pply
t
o
t
he
m
otions
o
f
t
he
p
rimary
ssion
p
roducts.
H
owever,
t
he
e
nergies
a
nd
m
omenta
a
ssoci-
ated
w
ith
t
he
n
eutrons
a
nd
p
hotons
a
re
r
elatively
s
mall,
s
o
m
omentum
c
onservation
ca
n
b
e
a
ssumed
t
o
rst
o
rder.
T
he
k
inetic
e
nergies
o
f
t
he
l
ight
a
nd
he
avy
ssion
products (E
L
and E
H
, respectively) relate to their masses (M
L
and M
H
, respectively)
a
ccording to the relationship
E E M M
L H H L
= .
Thus,
t
he
k
inetic
e
nergy
a
nd
v
elocity
o
f
t
he
l
ight
f
ragment
i
n
a
n
a
symmetr