V. Shiltsev

High energy particle colliders: past 20 years, next 20 years and beyond

Particle colliders for high energy physics have been in the forefront of scientific discoveries for more than half a century. The accelerator technology of the collider has progressed immensely, while the beam energy, luminosity, facility size and the cost have grown by several orders of magnitude. The method of colliding beams has not fully exhausted its potential but its pace of progress has greatly slowed down. In this paper we very briefly review the method and the history of colliders, discuss in detail the developments over the past two decades and the directions of the R and D toward near future colliders which are currently being explored. Finally, we make an attempt to look beyond the current horizon and outline the changes in the paradigm required for the next breakthroughs.

Collimation with Hollow Electron Beams

A novel concept of controlled halo removal for intense high-energy beams in storage rings and colliders is presented. It is based on the interaction of the circulating beam with a 5-keV, magnetically confined, pulsed hollow electron beam in a 2-m-long section of the ring. The electrons enclose the circulating beam, kicking halo particles transversely and leaving the beam core unperturbed. By acting as a tunable diffusion enhancer and not as a hard aperture limitation, the hollow electron beam collimator extends conventional collimation systems beyond the intensity limits imposed by tolerable losses. The concept was tested experimentally at the Fermilab Tevatron proton-antiproton collider. The first results on the collimation of 980-GeV antiprotons are presented.

Tevatron Electron Lenses: Design and Operation

The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

Generation and diagnostics of uncaptured beam in the Fermilab Tevatron and its control by electron lenses

In the Collider Run II, the Tevatron operates with 36 high intensity bunches of 980 GeV protons and antiprotons. Particles not captured by the Tevatron RF system pose a threat to quench the superconducting magnet during acceleration or at beam abort. We describe the main mechanisms for the origination of this uncaptured beam, and present measurements of its main parameters by means of a newly developed diagnostics system. The Tevatron Electron Lens is effectively used in the Collider Run II operation to remove uncaptured beam and keep its intensity in the abort gaps at a safe level.

Experimental Demonstration of Colliding-Beam-Lifetime Improvement by Electron Lenses

We report the first experimental demonstration of compensation of beam-beam interaction effects in high-energy particle collider by using space-charge forces of a low-energy electron beam. In our experiments, an electron lens, a novel instrument developed for the beam-beam compensation, was set on a 980-GeV proton bunch in the Tevatron proton-antiproton collider. The proton bunch losses due to its interaction with antiproton beam were reduced by a factor of 2 when the electron lens was operating. We describe the principle of electron lens operation and present experimental results.

Tevatron Beam Halo Collimation System: Design, Operational Experience and New Methods

Collimation of proton and antiproton beams in the Tevatron collider is required to protect CDF and D0 detectors and minimize their background rates, to keep irradiation of superconducting magnets under control, to maintain long-term operational reliability, and to reduce the impact of beam-induced radiation on the environment. In this article we briefly describe the design, practical implementation and performance of the collider collimation system, methods to control transverse and longitudinal beam halo and two novel collimation techniques tested in the Tevatron.

Overview of the Tevatron collider complex: goals, operations and performance

For more than two decades the Tevatron proton-antiproton collider was the centerpiece of the worlds high energy physics program. The collider was arguably one of the most complex research instruments ever to reach the operation stage and is widely recognized for numerous physics discoveries and for many technological breakthroughs. In this article we outline the historical background that led to the construction of the Tevatron Collider, the strategy applied to evolution of performance goals over the Tevatrons operational history, and briefly describe operations of each accelerator in the chain and achieved performance.

Accelerator physics at the Tevatron Collider

Introduction.- Beam Orbits and Optics, Methods Used at the Tevatron Accelerators.- Magnets and Magnetic Field Effects.- Longitudinal Beam Manipulations.- Collective Instabilities in the Tevatron Collider Run II Accelerators.- Emittance Growth and Beam Loss.- Antiproton Production and Cooling.- Beam-Beam Effects and Their Simulations.- Beam Instrumentation.- Appendix A.

The Legacy of the Tevatron in the Area of Accelerator Science

For more than 25 years, the Tevatron was the highest-energy accelerator in the world. It provided the first access to particle collisions beyond 1 TeV and achieved an ultimate performance that was a factor of 400 beyond the original design goals. This article reviews the many formidable challenges that were overcome, and the knowledge gained, in building, operating, and improving the Tevatron during its lifetime. These challenges included the first operation of an accelerator based on superconducting magnets; production of antiprotons in sufficient numbers to support a usable luminosity; management of beam–beam, intrabeam, and other collective effects; novel manipulations of the beam longitudinal phase space; and development and application of a wide variety of innovative technologies. These achievements established the legacy of the Tevatron as the progenitor of all subsequently constructed high-energy hadron colliders.

Mikhail Lomonosov and the dawn of Russian science

Curiously unsung in the West, Lomonosov broke ground in physics, chemistry, and astronomy; won acclaim as a poet and historian; and was a key figure of the Russian Enlightenment.