We have studied and made use of backward (180°) elastic scattering of 600 and 800 MeV protons as the experimental tool to search for the presence of nuclear states of very high binding energy, suggested by Feenberg and Primakoff and by Lee and Wick. This method, tested on a variety of targets, found no evidence for condensed nuclei (of 100 mb cross section) at a level of ${10}^{-8\mathrm{}}$ per target nucleus.

NUCLEAR REACTIONS Upper limit to fraction of condensed nuclei in Be, C, Cu, Ta, Au, Pt targets by measurement of backscattering of 600 and 800 MeV protons.

• Received 18 August 1975

DOI:https://doi.org/10.1103/PhysRevC.13.737