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