Neutron-proton Bremsstrahlung at 4.8 MeV

The differential cross section for neutron-proton bremsstrahlung has been measured at an incident energy of 4.8 MeV and outgoing nucleon angles of θn = 35°, θp = 25°. An upper limit of was obtained. The experimental method was unusual in that the hydrogen target was a stilbene scintillation crystal, which also served as recoil proton detector, and the bremsstrahlung photon was detected in addition to the two nucleons. A theoretical estimate of the cross section corresponding to that measured in this experiment was made using an on-shell approximation and gave a result of 89 μb · sr−2. The measured upper limit exceeds this and other theoretical predictions but nevertheless represents a marked improvement over previous measurements of n-p bremsstrahlung at energies below 100 MeV