Proton removal from 8B, 9C, and 12C on Si at 20-70 MeV/nucleon

A Si detector telescope, in which alternating thick and thin Si elements served as both targets and detectors, was used to measure the energy dependence of the inclusive one-proton-removal cross sections σ1p of ⁸B, ⁹C, and ¹²C on a Si target. A similar detector telescope was used to measure both σ1p and σ2p for ⁹C; σ2p, of ⁹C is more than twice as large as σ1p of ⁹C and almost as large as σ1p of ⁸+B. The measurements were compared with shell model calculations using eikonal reaction theory. The quenching factors Rs (the ratio of the measurement to the theoretical prediction) for ⁸B and ⁹C were near unity, as at higher energies. They also agreed with those measured recently for those nuclei on a C target at 75 MeV/nucleon. For ¹²C the quenching is greater with Rs=0.44±0.03. This is comparable to the value 0.53±0.02 deduced at energies above 1 GeV/nucleon.

Duke Scholars

Author John H Kelley Physics