Complete kinematics measurement of the 11B(p,γ)3α reaction

One of the first nuclear reactions measured after the invention of the accelerator by Cockroft and Walton was 11B+p, measured by Rutherford and Oliphant in 1933 [1, 2]. This reaction, however, is not yet fully understood at low incident proton energies [3], and the present paper therefore presents a new measurement with complete-kinematics data utilising modern large-area segmented silicon-strip detectors. The aim of the measurement is twofold: firstly, to fully characterise the triple-α decay of the T=1, 2+ state at 16.11 MeV in 12C; secondly, to search for γ decay of the 2+ state to lower lying states, in particular the newly suggested 2+ state around 9–10 MeV [4]. The isovector M1 population of lower lying 2+ states is strongly favoured over isovector E2 transitions to 0+ states, and the method is therefore a promising method to elucidating this timely question.