Investigation of the quasielastic proton pair knock-on process from Li6 and C12 nuclei by 640-MeV protons
Nadezhdin V.S. , Petrov N.I. , Rozanova A.M., Satarov V.I.
The (р,Ър) reaction was first reported in Ref. 1. This article presents results of a more detailed investigation of this reaction using equipment consisting of triggered spark chambers which permit determination of the energy and outgoing direction of each of the three protons. The experimental geometry corresponds to the scattering of a proton by a pair of nuclear protons at the angle of 118° in the cms of the colliding particles. Two spark chambers were placed to the left of the proton beam at angles of 22.5 and 31.5"; the third chamber was placed to the right of the beam at 80°. The energy of each proton was determined from its range in a chamber in the interval from 135 to 315 MeV. The graphite target was 3.51 g/cm2 thick; the lithium target consisted of 90% Li6 isotope and its thickness was 1.50 g/cm2. The data was recorded photographically. When processing the photographs care was taken to completely exclude the contribution of events originating outside a target, and also the background associated with the random triggering of the camera control system.