Breakup ofHe3projectiles at an incident energy of 43.3 MeV/nucleon

Abstract

Deuteron spectra from the Al, Co, Nb, Au( He, d) reactions at an incident energy of 130 MeV (43.3 MeV/nucleon) have been measured in an angular range H~, b =7. 5' -21' in 1. 5' steps. Target mass and angular dependences of the centroid energy E"the full width at half maximum I, and the differential cross sections of the breakup peak are presented. The width of the peripheral region where the breakup process is assumed to take place has been estimated to be about 0.7 fm.troid energy E"and the total cross section ub"of the breakup peak.Energy spectra of particles emitted from interaction of loosely bound light projectiles with targets generally exhibit a broad "bump" centered at an energy corresponding approximately to the beam velocity. 'T his bump has been attributed to the projectile breakup process occurring at the periphery of the target nucleus. Theoretical calculations"" based on a flying spectator mechanism have been successful in describing the main features of the experimental data. However, on the experimental side, to our knowledge there has been no effort made so far to extract the "true" breakup peak from the ('He, d) reaction by subtracting the underlying physical continuum, just as in the case of giant resonance'~' and ('He, t)-bumps studies. It is obvious (e.g. , see Fig. 1) that this continuum under the breakup bump generally constitutes a significant part of the cross section.In this Brief Report, we present experimental results on the 'He-projectile breakup process at ari in- Experimental details have been described elsewhere. Examples of the measured deuteron spectra are shown in Fig. 1

Phenomenological model for light-projectile breakup

“…The systematic peak energies for (d,p), ( 3 He,d), and ( 3 He,p) breakup obtained from Eqs. (1)(2)(3)(4) are shown along with the experimental values in Fig. 2.…”

“…With these assumptions, values of θ 0 for the three heaviest targets could be determined. [2]. Figure 9 shows fairly constant values for low C a /E inc , giving an upper limit to θ 0 .…”

“…12. The data on ( 3 He,d) breakup includes results at 70, 90, and 110 MeV [1] and at 130 MeV [2]. The published data of Matsuoka et al [1] consist of energy spectra measured at several forward angles for a 90 Zr target, plus spectra at a laboratory angle of 13 deg for a variety of targets at…”

“…12. 70 and 90 MeV. The 130 MeV data of Djaloeis et al [2] cover a range of angles for four targets. The published graphs for both data sets show spectra from all angles for a given target or from all targets at a fixed angle using a single linear scale.…”

“…Inclusion of these effects will enable a better assessment of the initial particlehole configuration in the exciton statistical preequilibrium model. The importance of projectile breakup is most obvious for incident deuterons because of their low internal binding energy, but the breakup mechanism also makes significant contributions for reactions induced by 3 He ions [1,2] and, at sufficiently high incident energies, by α particles [3,4].…”