Low-energy stripping of Kr+, Xe+, and Pb+ beams in helium and nitrogen

Abstract

Stripping efficiencies for Kr+, Xe+, and Pb+ beams in helium and nitrogen gas targets have been measured at energies varying between 0.8 and 2.0 MeV. The stripping yields were determined for different target densities, ranging from single-collision conditions to equilibrium. Based on these results, approximate predictions of the equilibrium charge state distributions for low velocity (v/c=0.0040–0.0060) heavy ions with 28<Z<92 in collisions with helium atoms are made. Furthermore, measurements of the small-angle scattering of these heavy ion beams in collisions with dilute helium and nitrogen gases are reported. The presented results are important in view of a proposed postacceleration scheme for low-energy radioactive ion beams using a linac. These data show that helium generally produces higher yields of 2+ and 3+ ions and that the optimal choice of gas thickness for the proposed application is somewhat less than that required for equilibrium.