Zum Kernphotoeffekt am Ar40 und Ar38
Liquid Argon was irradiated with bremsstrahlung from 18 to 31 MeV endpoint energy in steps of 2 MeV. The yields of the reactions Ar40(γ, n)+(γ, p) and Ar38(γ, n) were measured by detecting the 269a and the 35d rest activity with a low-level-counter. Cross section curves for the (γ, n)-processes could be found from the yield values, and they allowed together withσN, σ(γ, p) andσ(γ, np) a determination ofσ(γ, 2n) and σγabs for Ar40. The integrated cross section forσ(γ, n) from threshold to 33 MeV yields (200±40) MeVmb for Ar40 and (210±40) MeVmb for Ar38, the corresponding value for σγabs being (450±60) MeVmb for Ar40.