Direct pickup and knockout processes in inclusive $(p,dx$) reactions at 42–392 MeV

Inclusive $(p,dx)$ reactions at 42–392 MeV are investigated to understand quantitatively the roles of direct pickup and knockout. These two processes are formulated and introduced into the intranuclear cascade model. The calculated spectral shapes and magnitudes of the double-differential cross sections agree well with all experimental observations over the entire ranges of emission energy and laboratory angle. The model reveals the contributions of pickup and knockout in terms of incident-energy dependence. Direct pickup accounts for the highest energy domain of the spectra of not only discrete but also continuum regions with excitations up to around 45 MeV. Knockout becomes increasingly important with incident proton energy. It is negligible at 42 MeV, occupies the lower half of spectra at 90 MeV, and above 300 MeV is responsible for most of each energy spectrum except the part at highest energy. This trend is very similar to that of $(p,nx)$ cross sections. The indirect pickup component appears at these energies, as suggested in previous studies.

Figure 1

Spectra of $42\text{−}\mathrm{MeV}{}^{27}\mathrm{Al}(p,dx)$ reactions at $30\text{–}{90}^{\circ }$. Lines and dots show results of present model and experiment, respectively. To avoid overlap, factors indicated in the figure are multiplied.

Figure 2

As Fig. 1 but for 68 MeV.

Figure 3

As Fig. 1 but for 90 MeV.

Figure 4

As Fig. 1 but for 300 MeV.

Figure 5

As Fig. 1 but for 392 MeV.

Figure 6

Contributions of direct pickup (solid line) and knockout (broken line) for 42-MeV ${}^{27}\mathrm{Al}(p,dx)$ at ${30}^{\circ }$.

Figure 7

As Fig. 6 but for incident energy of 68 MeV.

Figure 8

As Fig. 6 but for incident energy of 90 MeV.

Figure 9

Contributions of direct pickup (solid line), knockout (broken line), and indirect pickup (dash-dotted line) for 300-MeV ${}^{27}\mathrm{Al}(p,dx)$ at ${20}^{\circ }$.

Figure 10

Cross sections of knockout production for deuterons (dots) and neutrons (solid line) as function of incident proton energy.