(p, pxn) and (p, xn) reactions and mechanisms onCs133at 550 MeV

The mechanism of the ($p, \mathrm{pn}$) reaction on ${}_{}{}^{133}{}_{}{}^{}\mathrm{Cs}$ with 550 MeV protons was deduced by measuring the recoil angular distribution between 0° and 180°, and the differential range distribution at 0° and 90°, for ${}_{}{}^{132}{}_{}{}^{}\mathrm{Cs}$ recoil nuclei. Similar measurements were made for the ($p, p4n$) and ($p, 3n$) reaction products from ${}_{}{}^{133}{}_{}{}^{}\mathrm{Cs}$. Cross sections were also measured for the production of ($p, \mathrm{pxn}$) and ($p, \mathrm{xn}$) products. The experimental data were compared to predictions derived from Monte Carlo cascade and evaporation calculations, as well as from simple kinematic models of possible reaction mechanisms. The results indicate that about 80% of the ($p, \mathrm{pn}$) reaction takes place by ($p, p^{\prime }$) events followed by neutron evaporation.