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Insulating (MYLAR), semi-insulating (MYLAR-Au) and conducting foils have been bombarded by very energetic 64 MeV u-1 78Kr32+ ions. The velocity spectra of fast electrons emitted in the backward and forward directions have been measured and analyzed as a function of the elapsed time in the run. A shift of binary encounter and convoy electrons emitted in the forward direction toward lower velocities has been observed with insulating targets. No such shift occurs with metallic targets. The surface potential evolves with time (i.e. ion fluence) both at forward and backward emission angle. It is shown that strong bulk charging of insulating targets leads to a positive potential as high as 9 kV before charge breakdown. [ABSTRACT FROM AUTHOR]

Doubly differential electron velocity spectra induced by 36Ar18 + (95 MeV/u) from thin target foils (C, Ni, Ag, Au) were measured at GANIL (Caen, France) by means of the ARGOS multidetector 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. [ABSTRACT FROM AUTHOR]

Abstract: Two-particle correlation functions, involving protons, deuterons, tritons, and α-particles, have been measured at very forward angles (), in order to study projectile-like fragment (PLF) emission in = 44 and 77 MeV 40Ar + 27Al collisions. The observed correlations are similar for the two reactions at and 77 MeV, except for peaks originating from resonance decays, which are larger at the lower bombarding energy. Particle-velocity gated correlation functions are presented, and possible implications on the time sequence of the light charged particles, emitted from the PLF, are discussed. [Copyright &y& Elsevier]

Abstract: Storage rings as the ESR and the future NESR in the FAIR project are unique tools to study the dynamics of electron-ion and ion-atom collisions in the realm of strong perturbations and short interaction times. A telling sign of the character of such collisions are the electrons emitted into the continuum. For high Z projectiles and low Z targets the projectile centred continuum is dominating. Precision studies of these electrons emitted in relativistic collisions thus are of paramount importance for an understanding of the ionization mechanisms active in transferring electrons into the continua. Forward electron spectroscopy thus appears to be the tool of choice. For high precision studies in collision spectroscopy of high Z projectiles we have implemented an imaging forward electron spectrometer into the ESR supersonic jet target zone. In combination with a reaction microscope to be implemented next this enables investigations of several fundamental processes ranging from kinematically complete studies of multiple ionization and (e,2e) on ions to radiative and non-radiative electron transfer processes to the projectile continuum and for the first time kinematically complete measurements of the short-wavelength limit of the electron nucleus Bremsstrahlung. We report first results. [Copyright &y& Elsevier]