ABSOLUTE CROSS-SECTION FOR D(HE-4, D)HE-4 FORWARD SCATTERING

The D(He-4, D)He-4 differential cross section for forward scattering o f deuterons by helium ions has been measured, with an estimated precis ion of +/- 5%, in the range 1-3 MeV at the scattering angles of 20-deg rees, 25-degrees, 30-degrees, 35-degrees and 40-degrees. Deuterated po lystyrene (C-8D8)n films spun on Si wafers were used for the measureme nts, enabling the forward scattering cross section to be determined di rectly with reference to the He-4 backscattering cross section of carb on (which was, in turn, referenced to the Rutherford cross section for He-4 on Cu). The D(He-4, D)4 He cross section exhibits a resonance at 2.135 +/- 0.01 MeV, with approximately 60 keV FWHM, the amplitude of which is strongly dependent on scattering angle. For the rest of the e nergy range, the cross section is featureless, and can be fitted well by a simple polynomial.