In a previous paper (Devons 1939) the author has discussed the possibility of observing resonance phenomena in the scattering of
α
-particles by light nuclei, and the experimental results given there show that in general resonances in scattering are observable for light nuclei of atomic number less than about 12 and for
α
-particle energies about equal to or greater than the potential barrier height. In the case of the scattering by helium nuclei the classical coulomb scattering is very small, and therefore anomalies in the scattering due to excited states of Be
8
, the compound nucleus formed by He
4
and an
α
-particle, should be comparatively easy to detect. In addition no disintegration is possible with
α
-particles of the energies used (less than 8.5 MeV), so that if the nucleus Be
8
is formed in an excited state it can only dissociate into two
α
-particles, and hence the width of any level of Be
8
excited by
α
-particle scattering in helium will be due practically entirely to elastic scattering. The investigation of the excited states of Be
8
by means of the scattering of
α
-particles by helium nuclei has a particular interest since the existence of a broad level of Be
8
with an excitation energy of about 3 MeV above the ground state, which is capable of splitting up into two
α
-particles, is postulated to account for the results of several disintegration experiments.
Distribution of Resonances in Scattering by
Thin Barriers
