Charge Dependence of Slow-Ion Energy Losses in Transmission Experiments

Modifications of the beam line, detector system, and use of Rutherford-scattered particles to correct for beam-current fluctuations, were made to increase the precision of heavy-ion energy-loss measurements in penetration experiments performed at the New York University Accelerator Facility. Ar+, Ar++, and Ar3+ ions were incident on the same domain of C, Al, and Au foils. The energy loss distributions of Ar+, Ar++, and Ar3+ ions after transmission through the foils were measured under identical conditions. We found an increase in the energy loss with increasing charge of the ions. The data are discussed in terms of the relation between the effective stopping-power charge of projectiles inside the solids and the ionic charge of particles incident on and emerging from the foils.