CROSS SECTION FOR THE REACTION Al27(γ, n)Al26

Abstract
The cross section for the reaction Al27(γ, n)Al26 has been remeasured by the determination of Al26 activity. The results are in agreement with an earlier value obtained by the activity method, but differ from the result obtained by neutron detection. The discrepancy is thought to be due to complexity in the Al26 decay scheme. The reaction threshold is measured as 13.4 ± 0.2 Mev., the maximum energy of positrons from Al26 is 3.2 ± 0.1 Mev., and the half-life is determined as 6.5 ± 0.1 sec.