Over recent years there has been marked growth in interest in the study of techniques of cosmic ray physics by astrophysicists and particle physicists. Cosmic radiation is important for the astrophysicist because in the farther reaches of the universe. For particle physicists, it provides the opportunity to study neutrinos and very high energy particles of galactic origin. More importantly, cosmic rays constitue the background, and in some cases possibly the signal, for the more exotic unconfirmed hypothesized particles such as monopoles and sparticles. Concentrating on the highest energy cosmic rays, this book describes where they originate, acquire energy, and interact, in accreting neutron stars, supernova remnants, in large-scale shock waves. It also describes their interactions in the atmosphere and in the earth, how they are studied in surface and very large underground detectors, and what they tell us.

It is perhaps surprising that a process which was one of the first to be studied on an atomic scale, and a process which first received attention over seven decades ago, continues to be the object of diverse and intense research efforts. Such is the case with the (seemingly) conceptually simple and familiar mechanism of electron impact ionization of atoms, molecules, and ions. Not only has the multi-body nature of the collision given ground to theoretical effort only grudgingly, but also the variety and subtlety of processes contributing to ionization have helped insure that progress has come only with commensurate work: no pain - no gain. Modern experimental methods have made it possible to effectively measure and explore threshold laws, differential cross sections, partial cross sections, inner-shell ionization, and the ionization of unstable species such as radicals and ions. In most instances the availability of experimental data has provided impetus and guidance for further theoretical progress.

For ten days at the end of September, 1987, a group of about 75 scientists from 21 different countries gathered in a restored monastery on a 750 meter high piece of rock jutting out of the Mediterranean Sea to discuss the simulation of the transport of electrons and photons using Monte Carlo techniques. When we first had the idea for this meeting, Ralph Nelson, who had organized a previous course at the "Ettore Majorana" Centre for Scientific Culture, suggested that Erice would be the ideal place for such a meeting. Nahum, Nelson and Rogers became Co-Directors of the Course, with the help of Alessandro Rindi, the Director of the School of Radiation Damage and Protection, and Professor Antonino Zichichi, Director of the "Ettore Majorana" Centre. The course was an outstanding success, both scientifically and socially, and those at the meeting will carry the marks of having attended, both intellectually and on a personal level where many friendships were made. The scientific content of the course was at a very high caliber, both because of the hard work done by all the lecturers in preparing their lectures (e. g. , complete copies of each lecture were available at the beginning of the course) and because of the high quality of the "students", many of whom were accomplished experts in the field. The outstanding facilities of the Centre contributed greatly to the success. This volume contains the formal record of the course lectures.

Photoabsorption, Photoionization, and Photoelectron Spectroscopy explores photoabsorption processes involving individual, isolated molecules in the wavelength or photon energy range from the ionization thresholds of molecules (usually in the vacuum ultraviolet region) through the soft and hard X-ray region and beyond the ""K edge."" The interaction between electromagnetic radiation and isolated molecules based on photoabsorption, photoionization, and photoelectron spectroscopy studies is described, along with the techniques for measurement of total and partial cross sections. This book is comprised of eight chapters and examines the decomposition of molecules and molecular ions as well as mildly excited (valence shell excitation) and highly excited (inner shell excitation) molecules. After providing a general theoretical background, it discusses certain classes of atoms and molecules and considers electromagnetic interactions with gases. The following chapters focus on photoabsorption below the first ionization limit; quasi-discrete states above the first ionization potential; and the ionization continuum. Total photoabsorption and photoionization cross sections for selected molecules are also considered, and the angular distribution of photoelectrons is analyzed. The various measurement techniques are described in the last chapter. This monograph will be of interest to radiation chemists, radiation physicists, photochemists, mass spectrometrists, and perhaps radiation biologists.

Electron-Molecule Interactions and Their Applications, Volume 1 presents a comprehensive account of electron-molecule interactions in high- and ultra-high-pressure gases and liquids. Topics covered include elastic scattering of electrons by molecules; excitation, ionization, and dissociation of molecules by electron impact; electron-molecule resonances; and electron attachment and detachment processes. This volume is comprised of seven chapters and begins with a discussion on non-resonant elastic scattering and rotational excitation of molecules by electrons, followed by a review of non-resonant vibrational and electronic excitation. The reader is then introduced to resonance effects in electron scattering; electron-induced ionization and dissociation of molecules; and electron-molecule resonances. The ionization mechanisms and types of ions produced are highlighted, along with differential ionization cross sections. The final two chapters focus on electron attachment and detachment processes, paying particular attention to modes of electron capture by molecules such as via negative-ion resonant states. The collisional dynamics for a few selected atomic reactants are also described. Physicists will find this book extremely helpful.