Total photoabsorption off the proton and deuteron at intermediate energies

Total photoabsorption cross section experiments at GRAAL are described. Measurements have been done in the energy range E-gamma = 600-1500 MeV, with liquid hydrogen and deuterium targets, using the laser back scattered gamma beam and the large aperture LAGRAN gamma E detector. Electromagnetic and hadron backgrounds have been analyzed. A subtraction method, using the empty target measurements, has been applied to derive directly sigma(tot) for the free proton and deuteron. Experimental results for sigma(tot) are compared to existing literature data. Large difference between the proton and deuteron, normalized by factor 2, in photoabsorption cross section is seen particularly in the D-15 nucleon resonance region.