The fourth course of the International School of Physics of Exotic Atoms took place at the "Ettore Majorana" Center for Scien tific Culture, Erice, from March 31 to April 6, 1984. As tradition, exotic atoms have been a tool for studying elec tromagnetic, weak and strong interactions at low energies. We felt it appropriate to have a full course devoted to a discussion of the information to be gained on the fundamental interactions from the study of low energy systems. In this kind of physics, which is characterized experimentally by very intense particle sources and very sensitive apparatuses, one can search for rare events and can perform precise measurements. Sensitive tests of the predictions of current theories of electro weak and strong interactions can thus be achieved. The course was attended by 54 participants from 23 institutes in 9 countries. The morning lectures reviewed the achievements of the field in the last few years and the afternoon seminars dealt with new results and projects.

This Seminar has been organized in Erice, in the frame of the Eloisatron project activities, with the special purpose of bringing together an interdisciplinary group of distinguished physicists with prominent interest in the development of the accelerators. Listening to the invited lectures, examining the new topics and reviewing ideas for the acceleration of particles to energies beyond those attainable in machines whose construction is under way or is now contemplated are all important moments of this Seminar that will offer to the Italian Physicists a very important opening over the scenario of the accelerators. In connection with the Eloisatron project developments future Workshop-Seminars are now envisioned, each one aimed to a very specific topic in the field of the particle accelerators. The Editors v CONTENTS Overview of Linear Collider Studies ... -. ... K. Johnsen Principles of Beat-Wave Accelerators ... ... 15 U. de Angelis, R. Fedele and V.G. Vaccaro Wake Field Acceleration. ... ... 29 W. Bialowons, H.D. Bremer, F. -J. Decker, M. v. Hartrott, H.C. Lewin, G. -A. Voss, T. Weiland, P. Wilhelm, Xiao Chengde and K. Yokoya Energy Efficiency and Choice of Parameters for Linear Colliders ... 45 J. Clauss A Two-Stage RF Linear Colliders using a Superconducting Drive Linac ... -. ... -. ... . . -. ... -- 67 \~. Schne 11 The Micro Lasertron. An Efficient Switched-Power Source of mm Wave 1 ength Radi at ion --. -. . -. ... . -. -. . . -. . . -. 89 R.B. Palmer Collider Scaling and Cost Estimation ... ... -- 105 R.B.

This book presents an account of the course "Spectroscopy of Solid-State Laser-Type Materials" held in Erice, Italy, from June 16 to 30, 1985. This meeting was organized by the International School of Atomic and Molecular Spectroscopy of the "Ettore Majorana" Centre for Scientific Culture. The objective of the course was to present and examine the recent advances in spectroscopy and theoretical modelling relevant to the interpretation of luminescence and laser phenomena in several classes of solid-state materials. The available solid-state matrices (e.g. halides, oxides, glasses, semiconductors) and the full range of possible activators (transition ions, rare earth ions, post-transition ions, actinides, color centres) were considered. By bringing together specialists in the fields of solid-state luminescence and of solid-state laser materials, this course provided a much-needed forum for the critical . assessment of past developments in the R&D of solid-state lasers. Additional objectives of the meeting were to identify new classes of host/activator systems that show promise of laser operation; to alert researchers in solid-state luminescence to current technological needs for solid-state tunable lasers operating in the visible and infrared spectral regions; and generally to provide the scientific background for advanced work in solid state lasers. A total of 71 participants came from 54 laboratories and 21 nations (Austria, Belgium, Canada, F.R. of Germany, France, Greece, Ireland, Israel, Italy, the Netherlands, P.R. of China, Poland, Rumania, Sweden, Switzerland, South Korea, Spain, Turkey, United Kingdom, U.S.A. and U.S.S.R.).

The NATO Advanced Study Institute on Physios of St~ong Fields was held at Maratea/Italy from 1-14 June, 1986. The school was devoted to the advances, theoretical and experimental, in physics of strong fields made during the past five years. The topic of the first week was almost exclusively quantum electrodynamics, with dis cussions of symmetry breaking in the ground state, of the physics of strong fields in heavy ion collisions and of precision tests of perturba tive quantum electrodynamics. The famous positron lines found at GSI (Darmstadt) and the related question "new particle versus vacuum decay" - (yes or no or both) - constituted the center of experimental advances. This was followed in the second week by the presentation of a broad range of other areas where strong fields occur, reaching from nuclear physics over quantum chromodynamics to gravitation theory and astrophysics. We were fortunate to be able to calIon a body of lecturers who not only made considerable personal contributions to this research but who are also noted for their lecturing skills. Their enthusiasm and dedication for their work was readily transmitted to the students resulting in a very suc cessful school.

Introduction to Gauge Field Theory provides comprehensive coverage of modern relativistic quantum field theory, emphasizing the details of actual calculations rather than the phenomenology of the applications. Forming a foundation in the subject, the book assumes knowledge of relativistic quantum mechanics, but not of quantum field theory. The book

The second course of the International School on Physics with Low Energy Antiprotons was held in Erice, Sicily at the Ettore Majorana Centre for Scientific Culture, from May 20 to May 31, 1987. The School is dedicated to physics accessible to experiments using low energy antiprotons, especially in view of operation of the LEAR facility at CERN with the upgraded antiproton source AAC (Antiproton Accumulator AA and Antiproton Collector ACOL). The first course in 1986 covered topics related to fundamental symmetries. This book contains the proceedings of the second course which focused on spectroscopy of light and heavy quarks. These proceedings contain both the tutorial lectures and contri butions presented by participants during the School. The papers are organized in four sections: The first section includes theoretical reviews. Section II contains experimental reviews and covers the results in meson spectroscopy from DM2, MARK III, GAMS and n-WA76. Section III presents the new meson spectroscopy experiments in pre paration at CERN and Fermilab: Crystal Barrel, OBELIX, Jetset and E760. Section IV is dedicated to LEAR and to future facilities where meson spectroscopy would be a principal component of the physics programme. We should like to thank Dr. Alberto Gabriele and the staff of the Ettore Majorana Centre who provided for a smooth running of the School and a very pleasant stay. We are particularly grateful to Mrs. Anne Marie Bugge for her crucial help during the preparation and running of the School and for the editing of these Proceedings.