Ionization Of Solids By Heavy Particles

This book collects the papers presented at the NATO Advanced Research Workshop on "Ionization of Solids by Heavy Particles", held in Giardini-Naxos (Taormina), Italy, on June 1 -5, 1992. The meeting was the first to gather scientists to discuss the physics of electron emission and other ionization effects occurring during the interaction of heavy particles with condensed matter. The central problem in the field is how to use observations of electron emission and final radiation damage to understand what happens inside the solid, like excitation mechanisms, the propagation of the electronic excitation along different pathways, and surface effects. The ARW began with a brief survey of the field, stressing the unknowns. It was pointed out that ionization theories can only address the very particular case of weak perturbations. For this problem, this meant high speed, low-charged projectiles (a perturbation treatment of interactions with slow, highly charged ions was later presented). Only semi-empirical models exist for velocities lower than the Fermi velocity in the solid, which can be used to predict kinetic electron emission yields. These models, however, do not address the basic questions about the mechanisms for electron excitation, transport and escape through the surface layer.

The emission of electrons from solid surfaces bombarded by slow neutral and ionized heavy particles (atoms, molecules) is reviewed both theoretically and in the light of recent experimental studies by leading groups in the field. The book integrates physics of ion beams, surfaces and chemical physics, and serves both as a reference work for researchers and a textbook for graduate students.

The emission of electrons from solid surfaces bombarded by slow neutral and ionized heavy particles (atoms, molecules) is reviewed both theoretically and in the light of recent experimental studies by leading groups in the field. The book integrates physics of ion beams, surfaces and chemical physics, and serves both as a reference work for researchers and a textbook for graduate students.

This book offers a concise presentation of theoretical concepts characterizing and quantifying the slowing down of swift heavy ions in matter. Although the penetration of charged particles through matter has been studied for almost a hundred years, the quantitative theory for swift penetrating ions heavier than helium has been developed mainly during the past decade and is still progressing rapidly. The book addresses scientists and engineers working at accelerators with an interest in materials analysis and modification, medical diagnostics and therapy, mass spectrometry and radiation damage, as well as atomic and nuclear physicists. Although not a textbook, this monograph represents a unique source of state-of-the-art information that is useful to a university teacher in any course involving the interaction of charged particles with matter.

The term convoy electron refers to those electrons ejected in fast ion-atom and ion-solid collisions closely matched in vector velocity to that of the incident heavy particles responsible for their ejection. Similarities and differences among electrons ejected into such states through binary electron capture to continuum and electron loss to continuum processes in single ion-atom encounters are compared and contrasted to more complex ejection processes occurring in solid targets. Puzzles posed by the apparent strong projectile Z dependence but weak emergent ion charge dependence of the yield in the case of solid targets are reviewed. Very recent progress in resolving these puzzles has been made by recent observations that the apparent mean free path for electron scattering out of the forward direction within the target is observed to be an order of magnitude greater than that for free electrons of equal velocity provided the projectile charge is high. 13 references, 2 figures, 1 table.

Edited by E.P. Velikhov

The extensive use of low-energy accelerators in non-nuclear physics has now reached the stage where these activities are recognized as a natural field of investigation. Many other areas in physics and chemistry have undergone similarly spectacular development: beam foil spectroscopy in atomic physics, studies in atomic collisions, materials implantation, defects creation, nuclear microanalysis, and so on. Now, this most recent activity by itself and in its evident connec tion with the others has brought a new impetus to both the funda mental and the applied aspects of materials science. A summer school on "Material Characterization Using Ion Beams" has resulted from these developments and the realization that the use of ion beams is not restricted to accelerators but covers a wide energy range in the developing technology. The idea of the ion beam as a common denominator of many act1v1t1es dealing with surface and near-surface characterization was enthu siastically received by many scientists and a school on this subject received the positive endorsement of NATO. The Advanced Study Institute on Materials Science has assumed for us the status of an "institution" leading to better contact among the many laboratories engaged in this field. The fourth Institute in this series was held in Aleria, Corsica, between August 22 and September 12, 1976.

Comprehensive guide to an important materials science technique for students and researchers.