Authors: A. Bürgi, M. Gonin, M. Oetliker, P. Bochsler, J. Geiss, T. Lamy, A.
Brenac, H.J. Andrä, P. Roncin, H. Laurent, and M.A. Coplan
Reference: J. Appl. Phys. 73 (1993) 4130-4139.
Abstract:
In order to calibrate a novel type of time-of-flight mass spectrometer
to be flown in the solar wind, we have continued our investigation of
the charge exchange of low energy ions passing thin carbon foils. We
analyzed elements with widely different chemical properties: Ions of B,
C, F, Ne, Na, Si, S, Cl, Ar, K, and Fe in the energy range 0.5-3 keV/u
were passed through carbon foils with thicknesses between 1.1 and 10
mu g/cm2, and their charge state distributions and residual energies were
determined. It was found that (1) the charge state distribution behind
the foil is independent of the charge of the incident projectile, (2)
isotopes show the same charge exchange properties at equal velocities
as we have found previously, (3) at the lowest energies the charge
state distribution is no longer a function of the residual energy alone
but depends on both residual energy and foil thickness, (4) probable
differences in chemical properties between the front and back surfaces
of the foil have no detectable influence on the charge exchange
properties, and (5) strong electron shell effects manifest themselves
when results for different elements are compared. Journal of Applied
Physics is copyrighted by The American Institute of Physics.