These radioactive isotopes (preparation reactions, half-lives) are summarized in Table 8.4. They are produced in cyclotrons.

8.6.2 Sodium Isotopes

Na-24 can be prepared by the 23Na(n, Y)24Na reaction in nuclear reactors. The prod­uct is not carrier-free. Its half-life is 24 h, and it emits (3_ and hard gamma

radiation. Carrier-free 24Na isotopes can be produced in the 26Mg(d, a)24Na nuclear reaction, but this procedure is more expensive.

Na-22 can be prepared by the 23Na(n,2n)22Na nuclear reaction. The isotope con­tains an inactive carrier (Na-23). Since the (n,2n) nuclear reaction is endoergic, fast neutrons are needed. Its half-life is about 2 years, and it emits p and gamma radiation. Carrier-free Na isotopes can be produced in the Mg(d, a) Na nuclear reaction.