Heribert Koziol

Electron cooling experiment at CERN

Abstract Beams of 46 MeV protons have been cooled by means of electrons in the ICE (initial cooling experiment) storage ring. Six two-day runs starting in May 1979 have shown, for proton intensities of up to 3 × 108, a density increase in six dimensional phase space of over a factor of 106, with cooling times in momentum spread and betatron amplitudes of 0.3 and 1.2 s, respectively. The proton beam lifetime was increased by a factor of 40. Measurements of the evolution of momentum spread, beam profile, and neutral atom production rate are in reasonable agreement with theory.

The antiproton decelerator: AD

A simplified scheme for the provision of antiprotons at 100 MeV/c based on fast extraction is described. The scheme uses the existing p~ production target area and the modified Antiproton Collector Ring in their current location. The physics programme is largely based on capturing and storing antiprotons in Penning traps for the production and spectroscopy of antihydrogen. The machine modifications necessary to deliver batches of 1/spl times/10/sup 7/ p~/min at 100 MeV/c are described. Details of the machine layout and the experimental area in the existing AAC Hall are given.

Beam diagnostics for accelerators

This introductory course aims at a reasonably complete coverage of beam diagnostic devices used in linear and circular accelerators and in primary beam lines. The weight is on the concepts and the indication of variants, while for technical details the reader is referred to the literature. The present updated version replaces those from previous General Accelerator Physics Courses.

Measurement of antiproton lifetime using the ice storage ring

Antiprotons have been stored in the ICE Storage Ring and held for 85h with the help of stochastic cooling. We set a limit of at least 32 h for the antiproton lifetime (in its rest frame).

The Antiproton Decelerator: AD

Abstract In view of a possible future programme of physics with low-energy antiprotons, a simplified scheme for the provision of antiprotons at 100 MeV/ c has been studied. It uses the present target area and the modified Antiproton Collector (AC) in its present location. In this report the modifications and the operation are discussed.

Status of the antiproton decelerator: AD

A simplified scheme for the provision of antiprotons at 100 MeV/c in fast extraction is described. The scheme uses the existing p production target area and the modified Antiproton Collector Ring in their current location. Some modifications necessary to deliver batches of 1 × 10 7 antiprotons every minute at 100 MeV/c are described, details of the machine layout and the experimental area in the existing AAC Hall are given.

Experiments on Stochastic Cooling in ICE (Initial Cooling Experiment)

Recent experiments on stochastic cooling have resulted in cooling rates several orders of magnitude higher than obtained previously in the ISR. Two cooling systems reduce betatron oscillations. A third system reduces momentum spread, using the so-called filter method. The favourable signal-to-noise ratio of this method has led to cooling times (e-folding of peak density) of 15 s with 7.107 protons in ICE. Betatron cooling times are longer due to the lower signal-to-noise ratio. Simultaneous cooling in all three planes has yielded lifetimes of about 100 h, a value consistent with losses caused by single scattering on the residual gas. The existing stochastic cooling theory has been confirmed.

Beam Diagnostics at the CERN PS Booster

A description of all beam diagnostics equipment for the CERN PS Booster is given. The following items are discussed in more detail: -a computerized system of position pick-up electrodes, -a 900 MHz electromagnetic pick-up station, -the fast measurement of the betatron-tune and -the measurement line for the ejected beams (spectrometry and emittance measurements).

Beam Optics Studies on the Antiproton Accumulator

The CERN Antiproton Accumulator (AA) was designed to accumulate 6 x 1011 antiprotons per day, using the stochastic cooling technique. Its construction was completed within two years and the first beam circulated in early July 1980. This paper describes the conceptual design of the lattice and how multipole shim corrections were applied to develop the large betatron and momentum design acceptances. We also report how a sequence of such corrections, based on optics studies with proton beams, have been applied to the point that the machine is now approaching design performance.

The Closed Orbit Observation System of the CERN Antiproton Accumulator

The Antiproton Accumulator (AA) works at 3.5 GeV/c central orbit momentum, has 5O¿ m circumference, Q-values around 2 ¿ and a large dispersion, up to 10 m, over most of its circumference (see ref. 1 for description). Closed orbits have to be measured over the whole range of the very large momentum acceptance (6.5%) and at beam intensities as low as 5 × 109 particles (1.5 mA). Furthermore, the pick-up electrodes have to serve as clearing field electrodes and no straight section space was available for them. They have to be compatible with an UHV of 10-11 Torr and bakeable to 300°C. The AA closed orbit observation system therefore has several unusual features: a wide range of dimensions of the pick-up electrodes, adapted to beam size, up to 70 cm horizontal width; location inside the main magnets and quadrupoles; high input impedance head amplifiers, mounted directly on the vacuum chamber feedthroughs; electronic normalizers to provide the ratio of difference/sum signals; high precision for measuring orbits far from centre. Acquisition, calibration, data treatment and display are performed with the single, stand-alone, controls computer.