Production ofAr38andAr39in the interaction of gold and thorium with 1, 2.5, and 24 GeV protons

Abstract

Cross sections and thick-target recoil properties of $^{38}\mathrm{Ar}$ and $^{39}\mathrm{Ar}$, formed in the interaction of Au and Th with 1, 2.5, and 24 GeV protons, have been determined in order to study their variations with incident energy. The measurement of the experimental range, $2W(F+B)$, and of the forward-to-backward ratio $\frac{F}{B}$ permits (with the help of a mathematical formalism based on the two-step model) the determination of some characteristics of nuclear reactions; i.e., the mean kinetic energy of the observed products $〈T〉$, the mean forward component of the velocity imparted to the struck nucleus in the first step, $〈{v}_{\ensuremath{\parallel}}〉$, and the excitation energy ${E}^{*}$ of the residual nucleus after cascade. The results are discussed in terms of very asymmetric fission (at 1 GeV) and deep spallation (at 2.5 and 24 GeV) mechanisms. These results are very similar to those obtained for neutron-deficient krypton and xenon isotopes formed in thorium and presented in a previous publication from this laboratory.NUCLEAR REACTIONS Measured $\ensuremath{\sigma}$, $2W(F+B)$, and $\frac{F}{B}$ of $^{38}\mathrm{Ar}$ and $^{39}\mathrm{Ar}$ isotopes formed in interaction of Au and Th with 1, 2.5, and 24 GeV protons.