Measurement of yield and cross section for the 27Al(γ,2p) 25Na reaction with a clinical linear accelerator

A clinical electron linear accelerator was adapted for continuous energy selection and used to measure bremsstrahlung yield for the photonuclear reaction 27Al(γ,2p) 25Na from 24.0 to 32.0-MeV in 0.25 MeV steps. A germanium detector was used to measure the number of photoproduct γ-rays emitted. The yield values were analyzed for photonuclear cross section using PHONUC II, a program especially adapted for use with yield data from thick-target bremsstrahlung. The cross section shows distinct resonance peaks at 26.3+-0.3, 27.3+-0.4 and 30.3+-0.5 MeV. Possible theoretical origins of these resonances and applications of the reaction in accelerator energy calibration are discussed. (author)