Absolute total photoabsorption cross sections on nuclei in the nucleon resonance region

Abstract We present the results of an absolute measurement of the photoabsorption cross section on Li, C, Al, Cu, Sn, and Pb between 300–1200 MeV. In the Δ region our results confirm that the strength is conserved, while in the higher resonances region they show a 7–15% damping and a possible mass-number dependence of the photoabsorption cross section.