Mechanisms in Knockout Reactions

Abstract

We report the first detailed study of the relative importance of the stripping and diffraction mechanisms involved in nucleon knockout reactions, by the use of a coincidence measurement of the residue and fast proton following one-proton knockout reactions. The measurements used the S800 spectrograph in combination with the HiRA detector array at the NSCL. Results for the reactions 9Be(9C,8B+X)Y and 9Be(8B,7Be+X)Y are presented and compared with theoretical predictions for the two reaction mechanisms calculated using the eikonal model. The data show a clear distinction between the stripping and diffraction mechanisms and the measured relative proportions are very well reproduced by the reaction theory. This agreement adds support to the results of knockout reaction analyses and their applications to the spectroscopy of rare isotopes.

Systematic study ofp-shell nuclei via single-nucleon knockout reactions

“…Previous analyses of proton knockout from the light and stable nuclei, 12 C and 16 O, showed that spectroscopic factors obtained from such knockout reactions were consistent with those derived * grinyer@ganil.fr † Present Address: CEA, Centre de Saclay, IRFU/Service de Physique Nucléaire, F-91191 Gif-sur-Yvette, France.…”

“…The data set consists of a total of 10 inclusive singlenucleon knockout cross-section measurements performed at intermediate energies ranging between 80 and 120 MeV/u and that employed different reaction target materials (Be or C). A result from a previous experiment on the proton knockout from 9 C [12] has also been included in the present data set and was reanalyzed according to the formalism described below. In the present experiment, secondary beams of 7 Li, 9 Li, 10 Be, and 10 C were produced following projectile fragmentation of an 16 O primary beam accelerated to 150 MeV/u in the K500 and K1200 coupled cyclotrons at the National Superconducting Cyclotron Laboratory (NSCL).…”

“…The primary production targets were 9 Be. Secondary reaction targets were 188(2) mg/cm 2 [12] or 376(4) mg/cm 2 9 Be or 403(5) mg/cm 2 nat C. a Experimental result from Ref. [12].…”

“…Secondary reaction targets were 188(2) mg/cm 2 [12] or 376(4) mg/cm 2 9 Be or 403(5) mg/cm 2 nat C. a Experimental result from Ref. [12]. Table I) that was located at the the entrance of the A1900 fragment separator [13].…”

“…The diffractive or elastic component accounts for events that remove a nucleon from the projectile via an elastic interaction with the target. Through an exclusive measurement that also detected the removed protons following proton knockout reactions from 9 C and 8 B, it was demonstrated that this reaction model successfully described the relative contributions of the stripping and diffractive mechanisms to the inclusive cross sections [12].…”