CLUSTERING EFFECTS IN THE PHOTO-DISINTEGRATION OF HE-4

The total and the differential cross-sections, the angular and the energy correlations for the three-and four-body4He photodisintegration have been investigated, with a diffusion cloud chamber placed in a magnetic field and exposed to the 100 MeV electrosynchrotron of Torino University. The analysis seems to indicate that, in about 71% of the (γ, pn) events the photons are absorbed by a n-p pair, in about 15% of the events by a n-d pair and in about 14% of the events the particles photoemitted are not correlated. For the (γ, 2n2p) reaction, the results seem to suggest, as main reaction mechanism, the photoabsorption from a quasi-deuteron correlated to another quasi-deuteron, which are decomposed too. © 1979 Società Italiana di Fisica.