Beta Spectroscopy

β + -decay
In the case of positron decay and using similar arguments we obtain:
A
A +
Z
X →
Z−1X'
+ e + υ
Q
+
β
=
[m(
A
X) − m(
A
X') − 2m
e
]c
2
EC-decay
For the electron-capture process such as:
A − A
Z
X + e →
Z−1X'
+ υ
We obtain:
Q
−
β
=
[m(
A
X) − m(
A
X') ] c
−
B
n
where B n
is the binding energy of the captured electron
All the above expressions assume ß-decay between a specific state and the ground state. If
the final state is an excited state this must be taken into account.