L. C. Teng

Compensation of Chromatic Aberration in a Single Period Lattice

The requirement of high periodicity (even periodicity two) in a storage-ring lattice imposes a strong restriction on the number and type of insertions that can be included. On the other hand, since the insertions are matched only at one momentum, the ß-function error for an off-momentum orbit is generally greater In a one-period lattice. This large ß-error has several undesirable effects. All of these undesirable effects can be compensated or greatly reduced by judicious arrangement of betatron phasing and by the use of trim sextupoles. The design procedure and the resultant performance will be demonstrated for a model one-period lattice.

Progress Report on the POPAE Design Study

POPAE (Protons on Protons and Electrons) is a storage ring facility at the Fermilab on a scale suitable to permit the collision of 1000 GeV protons with 1000 GeV protons and with electrons of an energy compatible with that scale. In this paper, we summarize our work thus far on the lattice and layout of the proton storage rings. Though the 1000 GeV physical scale is maintained, the design is developed in a 400 GeV context. The proton rings form a racetrack, the two long straight sections of which are each about 1 km in length. Each long straight section contains a number of matched lattice insertions, as well as uncommitted space for additional development. Depending on the assumptions made concerning the beam-beam limit (as yet unknown experimentally), maximum luminosities are calculated to be in the range from 1033 to 1034cm-2 sec-1.

Phase space cooling and PP colliding beams of fermilab

It has recently been suggested1 that the present high energy synchrotrons at CERN and Fermilab could be operated as pp storage rings with a center-of-mass energy of some 800 GeV. The Fermilab Energy Doubler/Saver, in addition, would be quite suitable as a high performance storage ring, producing collisions at 2 TeV in the center-of-mass. In order to achieve useful luminosity it is necessary to: 1) collect antiprotons from ˜-80 GeV protons colliding on a stationary target, 2) cool the phase space of the initially diffuse ps, and 3) accumulate the cooled ps over cycles. Several methods have been devised to carry out this repetitive accumulation and cooling. 2,3,4

Lattice Insertions for POPAE

Four types of insertions are described for the six 200-m straight sections of POPAE. All have dispersion matched to zero. (1) Injection-ejection insertion - This has proper high-6 values and phase advances for horizontal injection and vertical ejection. (2) Phase-adjust insertion - The phase advance in this insertion is adjustable over a range of ~100°. (3) Generalpurpose insertion - The ß* is adjustable from 2.5 to 200 m and the crossing angle is adjustable from 0 to 11 mrad. (4) High-luminosity insertion - This gives an even lower ß* of 1 meter.

Proposals for Synchrotron Light Sources

Ever since it was first applied in the 1960s synchrotron radiation from an accelerating electron beam has been gaining popularity as a powerful tool for research and development in a wide variety of fields of science and technology. By now there are some 20 facilities operating either parasitically or dedicatedly for synchrotron radiation research in different parts of the world. In addition there are another 20 facilities either in construction or in various stages of proposal and design. The experiences gained from the operating facilities and the recent development of insertion devices such as wigglers and undulators as radiation sources led to a new set of requirements on the design of synchrotron radiation storage rings for optimum utility. The surprisingly uniform applicability and unanimous acceptance of these criteria give assurance that they are indeed valid criteria derived form mature considerations and experiences. Instead of describing the design of each of these new facilities it is, thus, more effective to discuss these desirable design features and indicate how they are incorporated in the design using machines listed as examples. 9 refs., 7 figs., 2 tabs.

Choice of Focusing Strength and Aperture for High Energy Synchrotrons and Colliders

At low energies and low intensities the considerations in the choice of the focusing strength (betatron tune v) for a synchrotron are the beam size and the orbit distortion due to field errors which, together, generate a geometrical requirement on the size of the beam pipe and the good field aperture. Indeed, the strong focusing principle was invented to reduce the necessary magnet aperture, thereby the cost of the magnets. The closed orbit distortion increases with v and was cited1 as the factor counteracting the desire to reduce the beam size indefinitely by going to arbitrarily strong focusing. At high energies and intensities and with modern technology this is no longer true. The beam size is generally negligibly small and the orbit distortion can be corrected to arbitrary desired accuracy. Studies of field errors and orbit distortions are now used for sizing the correction magnet system rather than the aperture. Other types of geometrical demands on the aperture arise from beam manipulations such as stacking and resonant extraction. These requirements tend to be local and can usually be satisfied by local lattice insertions (highor low-s, highor zero-dispersion etc.).

Heavy Ion Accelerators for Inertial Fusion

Heavy ion beams make a good driver for inertial fusion. Two types of accelerator are promising for delivering the requisit high current beams - the rf linac/storage ring system pursued at the Argonne National Laboratory and the induction linac scheme developed at the Lawrence Berkeley Laboratory. The progress at these laboratories is, however, regrettably slow due to lack of funding. The general requirements on the driver for heavy ion fusion are reviewed and the status of various R&D efforts is discussed.

POPAE - A 1000 Gev on 1000 Gev Proton-Proton Colliding Beam Facility

A proposal has been developed for the construction of a 1000 GeV on 1000 GeV colliding beam facility at Fermi National Accelerator Laboratory. To achieve the same 2000-GeV center-of-mass energy with a fixed target accelerator would require a beam of more than 2 × 106 GeV. The total circumference of the facility is 5520 m, including six straight sections, each 200 m long. Injection from the Fermilab main ring or Energy Saver/Doubler (ES/D) will be at the energy desired for interactions, thus avoiding the uncertainty, complication, and cost of accelerating very intense beams in the storage rings themselves. Each ring will require 570 superconducting dipole magnets, each 6.2 m long; the field required at 1000 GeV is 60 kG. For a proton current of 5A in each ring at 1000 GeV, the high-luminosity insertion is designed to give L = 4 × 1033 cm-2 sec-1. The proposal was developed during an intensive study from November 1975 to April 1976. This study drew not only on the experience of the CERN ISR2 and previous Fermilab designs, but also on studies of high energy storage rings made at Brookhaven National Laboratory (Isabelle)4 and at CERN (LSR).5