Biomedical Engineering Reference
In-Depth Information
Fig. 3.5
Shape of typical beta-particle energy spectrum.
Fig. 3.6
Decay scheme of
6
27
Co.
to determine the energy of the nuclear excited state from which the second pho-
ton is emitted: 1.173 MeV or 1.332 MeV? Appendix D lists a rare beta particle with
Q
1.491 MeV. This decay must go to a level in the daughter nucleus having an en-
ergy
2.823 - 1.491
=
1.332
MeV above the ground state. Thus we can conclude that
the 1.332 MeV photon is emitted last in the transition to the ground state. The decay
scheme is shown in Fig. 3.6. The arrows drawn slanting toward the right indicate
the increase in atomic number that results from
β
=
-
decay. The rare mode is shown
with a dashed line. No significant internal conversion occurs with this radionuclide.
