DETERMINATION OF THE SPIN ALIGNMENT IN HEAVY-ION REACTIONS WITH THE SPIN SPECTROMETER

Abstract A detailed procedure is outlined that permits one to deduce the spin direction in heavy-ion fusion reactions on an event-by-event basis using data from the spin spectrometer at the Holifield Heavy Ion Research Facility of Oak Ridge National Laboratory. The parameters that govern the ability of the spin spectrometer in determining the spin direction, namely the γ-ray multiplicity, the multipolarity, the crystal-to-crystal scattering, and coincidence summing, are examined in detail. Removal of detectors from the complete spectrometer causes large misalignment in the deduced spin distributions. A procedure to correct for this induced misalignment based on local density distributions is presented. Some results from measurement of angular distributions of α-particles using the spin alignment method are also discussed.