| E. De Filippo, G. Lanzano, H. Rothard, C. Volant,
S. Aiello, A. Anzalone, N. Arena, M. Geraci, F.
Giustolisi, A. Pagano
|
Doubly differential electron velocity spectra induced by $^{36}$Ar$^{18+}$
(95 MeV/u) from thin target foils (C, Ni, Ag, Au) were
measured at GANIL (Caen, France) by means of the ARGOS
multi-detector and the time-of-flight technique. The main features
observed in the forward spectra are convoy electrons, binary
encounter electrons, and (for the Au target only) a high velocity
tail which we attribute to a ``Fermi-shuttle\'\' acceleration
mechanism. Backward spectra do not show distinct structures. The
spectra allow us to determine absolute singly differential cross
sections as a function of the target material and the emission
angle. The convoy electron yield increases with the target atomic
number, but for C their yield is so small that our experiment is
not able to detect them. Absolute doubly differential cross
sections for binary encounter electron ejection from C targets are
well described by a transport theory which is based on the
relativistic electron impact approximation (EIA) for electron
production and which accounts for angular deflection, energy loss
and energy straggling of the transmitted electrons.
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