(p, pxn) Reactions ofBr79andBr81with 2.9-GeV Protons

Cross sections for the ($p, \mathrm{pxn}$) reactions of ${\mathrm{Br}}^{79}$ and ${\mathrm{Br}}^{81}$ have been measured at 2.9 GeV. The cross sections decrease monotonically as $x$ increases, and the decrease with increasing $x$ is faster for ${\mathrm{Br}}^{79}$ than for ${\mathrm{Br}}^{81}$. The results are compared with Monte Carlo cascade-evaporation calculations. The experimental values are larger than the calculated ones for $x\le 3$ but are in good agreement for $x=4-5\mathrm{}$. The systematics of ($p, \mathrm{pxn}$) reactions at high energies are considered for a number of targets. A quantitative analysis of the ($p, p3n$) and ($p, p4n$) reactions indicates that the evaporation process determines the variation in cross section from target to target.