MEASUREMENTS AND ANALYSES OF THE PHOTONUCLEAR REACTION YIELDS

Reactions induced by photons may be used as a probe for bonds and correlations between nucleons inside a heavy target nucleus. Electromagnetic radiation perturbs the nucleons only slightly unlike the influence of strongly interacting particles. The yield of (gamma, alpha) reactions could be used to test theoretical models assuming a complete a-clustering, or multi-quark objects in heavy nuclei. Relative yields of (gamma, n), (gamma, p), and (gamma, alpha) reactions have been measured at the bremsstrahlung end-point energy of 23 MeV with several targets. Much lower probability of (gamma, alpha) compared to (gamma, p) reactions is proved despite practically similar threshold and spin factors for both types of reactions. Alpha clustering in heavy targets is not supported. The mechanism of particle release in nuclear reactions is discussed and some details are clarified.