Toward storage and cooling of highly-charged ions in a Penning trap

In order to store highly-charged ions in a Penning trap for long periods, the densities of neutrals must be sufficiently low to prevent significant electron capture, and the ion temperature must be greatly reduced. Possibilities for forming spatially ordered states of the highly-charged ions appear to depend on ion-ion collisional cooling. The consequences of using stored positrons, or laser-cooled Be + ions, to collisionally cool the highly-charged ions are discussed with particular emphasis on expected effects at the lowest ion energies.