Lifetime studies of Ar-2p-vacancies travelling through solids

Studies are reported on the production of aluminium K X-rays in Ar+-Al collisions using varying thicknesses of thin aluminium foils. It is shown that the mechanism for X-ray production involves a double collision. Parameterization of the data allows one to infer the fraction of the argon beam inside the solid with a 2p-vacancy, the cross section for 2p-vacancy production and the average lifetime of the argon 2p-vacancy travelling through a solid. The lifetime may be related to the atomic state or outer electron configuration of the projectile in the foil. (Auth.)