Neutron-neutron effective range from quasifree scattering 2H(n, nn)p at 25 MeV

Abstract A neutron coincidence spectrum from the deuteron breakup 2 H(n, nn)p was measured at the kinematical condition of quasifree neutron-neutron scattering with 25 MeV neutrons in the entrance channel. The efficiencies of both scintillation detectors were calibrated in the same experimental arrangement as the breakup measurement was performed. The neutron flux was monitored by a proton recoil telescope. Absorption, double scattering and geometric conditions have been simulated by the Monte Carlo technique. From a fit based on the Ebenhoh-Bruinsma-Stuivenberg code with the neutron-neutron scattering length a nn = −16.6 fm for the effective range, the value r nn = 2.69 ± 0.27 fm was determined.