[en] On completion of the ACOL project, the increased beam intensity in the Antiproton Accumulator, AA, will be derived from extensions to the transverse and longitudinal acceptances via the new Antiproton Collector ring being constructed around the AA. Each of these extensions should give a factor of 3 to 4 improvement, i.e. an overall gain of at least 10 in anti-proton yield. The increased transverse acceptance has necessitated a redesign of the antiproton target station, which will be equipped to function with various passive and active targets. The antiproton collector lens will be a lithium lens, but high-current magnetic horns and a plasma lens are also under development. At start-up in 1987 antiproton yields into the ACOL nominal acceptance, Δp/p=6%, A_h, A_V = 200 mm-mrad, are expected to be as predicted. Target and collector lens lifetime limitations may make further gains more difficult than initially supposed, but if these can be overcome another factor of two is possible

[en] Following the decision to construct a collecting ring, with an enhanced acceptance for antiprotons, around the antiproton accumulator (AA) already in operation at CERN, it became necessary to redesign the transfer line between an improved target station and the new ring (AC). The new design had to satisfy two main requirements. Firstly, it should provide a transmission efficiency as high as possible for antiprotons in the AC acceptance; and secondly, collimate, in the target zone itself, as much as possible all secondary particles coming from the target but which are outside the AC acceptance. The design of the line must provide phase-space matching between the source and the AC, as well as having a region of momentum dispersion. It must also satisfy the constraints imposed by the apertures of the bending and quadrupole magnets which are to a large extent determined by the costs involved and the very limited distance available between the antiproton source and the ring. The design of the components for this line is also dependent on the necessity to provide remote-handling capability, particularly for those elements nearest the source. The detailed design is not yet completed

[en] The new Antiproton Accumulator Complex is now in operation at CERN. We consider the possibility of using this facility to create and store antideuterons and conclude that we could achieve an accumulation rate of about 2x10⁶ particles/day. No major rebuild of the rings is envisaged, but it is thought that modification to existing components and becoming operational would take about 5 to 6 months. We stress, however, that the operation of such a facility and the use of any stack of antideuterons for particle physics would be extremely taxing. (orig.)

[en] The construction of an electron beam ion source is in progress to give an ion current of fully stripped ions up to Argon¹⁸⁺. The present equipment is designed to study the focusing of the electron beam and the extraction of ions in order to determine the parameters for an operational source. Experiments on a Brillouin - focussed electron beam are currently carried out, and results from computer simulations of the magnetic field and the electron beam as well as results from experimental investigations on the electron gun and the magnetic field properties will be presented. (orig.)

[en] A new collector ring (AC) is being built around the existing Antiproton Accumulator (AA) machine in order to increase the accumulation rate of antiprotons. A much larger fraction of the particles produced at an improved target station will be transported to AC with a new 3.5 GeV/c beam line. This increased flux will be injected using a large aperture pulsed septum magnet capable of handling the 240 π.mm.mrad transverse emittances. Because the antiproton beam traverses the septum gap in air no vacuum problems arise and consequently the magnet can be of simple, glued construction. The beam requirements together with some of the unusual engineering design features of the 1.6 m long, 1 Tesla curved septum magnet are discussed

[en] A new collector ring (AC) is being built around the existing Antiproton Accumulator (AA) machine in order to increase the accumulation rate of antiprotons. A much larger fraction of the particles produced at an improved target station will be transported to AC with a new 3.5 GeV/c beam line. This increased flux will be injected using a large aperture pulsed septum magnet capable of handling the 240 π.mm.mrad transverse emittances. Because the antiproton beam traverses the septum gap in air no vacuum problems arise and consequently the magnet can be of simple, glued construction. The beam requirements together with some of the unusual engineering design features of the 1.6 m long, 1 Tesla curved septum magnet are discussed

[en] Antiprotons are produced for the CERN Antiproton Accumulator (AA) by focusing 26 GeV/c protons onto a 3 mm diameter, 11 cm long copper wire. Negatively charged particles with momenta about 3.5 GeV/c are focused by a short focal length coaxial horn and transported to the AA by a normal quadrupole focusing channel. The yield of antiprotons was found to be considerably less than anticipated (factor about 2) and the reason is presumed to be the assumption of too large a production cross-section in the original machine design proposal. Studies involving new horn design, introduction of an axial current (approx. = 150 kA) along the target and use of lithium lenses as an alternative to the magnetic horn are under way. Some preliminary measurements involving some of these techniques have been made, both to confirm the validity of calculations and to test the feasibility of building targets and focusing systems to withstand the mechanical forces and heat load due to the proton beam and the high pulsed currents

[en] There is an interest in accelerating atomic nuclei to produce particle beams for medical therapy, atomic and nuclear physics, inertial confinement fusion and particle physics. Laser Ion Sources, in which ions are extracted from plasma created when a high power density laser beam pulse strikes a solid surface in a vacuum, are not in common use. However, some new developments in which heavy ions have been accelerated show that such sources have the potential to provide the beams required for high-energy accelerator systems. copyright 1996 American Institute of Physics

[en] Following the pioneering work on lithium lenses at INP, Novosibirsk, a 2 cm diameter lens was designed and built at Fermilab as an antiproton collector for the antiproton source of the Tevatron I project. A lens of this type was tested at the CERN Antiproton Accumulator (AA) as an antiproton collector and then as a prefocusing element before the AA pulsed current target. In the latter case the purpose was to increase the proton beam convergence at the target to compensate the defocusing effect on the proton beam of the current in the target. As an antiproton collector the lithium lens performed as predicted increasing the antiproton yield into the AA by 40%. In the prefocusing configuration beam convergence and spot size on the target were considerably improved over the standard arrangement using a pulsed quadrupole triplet and the lens has survived 1.4 M pulsed quadrupole triplet and the lens has survived 1.4 M pulses of current from 290 to 350 kA in a 26 GeV/c beam of up to 1.4 10¹³ protons

[en] Following the pioneering work on lithium lenses at INP, Novosibirsk, a 2 cm diameter lens was designed and built at Fermilab as an antiproton collector for the antiproton source of the Tevatron I project. A lens of this type was tested at the CERN Antiproton Accumulator (AA) as an antiproton collector and then as a prefocusing element before the AA pulsed current target. In the latter case the purpose was to increase the proton beam convergence at the target to compensate the defocusing effect on the proton beam of the current in the target. As an antiproton collector the lithium lens performed as predicted increasing the antiproton yield into the AA by 40%. In the prefocusing configuration beam convergence and spot size on the target were considerably improved over the standard arrangement using a pulsed quadrupole triplet and the lens has survived 1.4 M pulses of current from 290 to 350 kA in a 26 GeV/c beam of up to 1.4 x 10¹³ protons