Differential cross-section measurements of the 2H(n, p)2n and 2H(n, d)n reactions and the n-n scattering length

Abstract

A magnetic quadrupole triplet spectrometer has been constructed at Ohio University in order to study neutron-induced charged particle reactions. Using this spectrometer, the proton spectra at forward angles from the kinematically incomplete 2H(n, p)2n break-up reaction have been measured at E n = 11 and 25 MeV with experimental energy resolutions of 175 and 300 keV, respectively. The angular distributions of the 2H(n, d)n elastic scattering have also been measured at E n = 9 and 11 MeV. Theoretical calculations based on the Faddeev three-body formalism have been performed using rank-one separable S- and P-wave nucleon-nucleon interactions. Comparison of breakup calculations with the data is sensitive to the value of the neutron-neutron scattering length a nn, and supports the value a nn = −16.6 ± 0.4 obtained from kinematically complete experiments.