Isotopes produced in gold by high energy protons.

Reactions of the type (p,n), (p,2n), (p,3n) can be expected as the energy of the incident proton is successively increased. Although limited experimental evidence for (α, jn) and(d, jn) reactions is available, there appears to be no (p,jn) reactions (other than j = 1,2) reported. The McGill 82” F.M. Cyclotron, with a proton energy range up to 100 Mev. is particularly suitable for this type of investigation. Gold, Z = 79, has a single stable isotope of mass 197 and (p>jn) reactions yield neutron-deficient mercury (z = 80) isotopes for which no data has been published except for j = 1. Since gold in very pure form is available and the mercury isotopes can be separated quite readily, it was decided to investigate this field. The experimental evidence required to check Weisskopf’s (7, 8, 9) theory is the threshold at which each isotope is formed and the relative isotope yield at each proton energy. However, before this information can be found, it is necessary to know some of the properties of the mercury isotopes e.g., half-lives, modes of decay, γ-ray energies. The purpose of this investigation was to determine these properties. This has been accomplished for isotopes up to Hg^191 i.e., j = 7. A mass spectrograph and a 180° beta-ray spectrometer, now under construction at this Laboratory, will be used to determine threshold energies and relative yields.[...