Snapshot of high-energy accelerator progress

27 May 1999

A major event in the international accelerator calendar is the triennial International Conference on High Energy Accelerators. The seventeeth such event, which was held recently in Dubna, Russia, provided a useful view of the current world scene.


Status reports from leading laboratories accounted for a major part of the programme of the International Conference on High Energy Accelerators, which was held at the Joint Institute for Nuclear Research (JINR) in Dubna near Moscow.

G Jackson described the increased luminosity for Fermilab’s Tevatron. An additional ring, the recycler, which utilizes permanent focusing magnets in the main injector tunnel, should be able to triple the antiproton intensity and provide luminosities as high as 1033 cm-2s-1.

The participation of JINR in international accelerator projects, such as CERN’s LHC collider and the TESLA superconducting linear collider, and the most recent results of the operation of the Nuclotron at JINR, was reported by A Sissakian. Deuteron beams from the Nuclotron for experiments with a thin internal target attain 3.2 GeV/nucleon, the intensity of circulating particles being 1.2 x 1010.

D Trines of DESY covered the HERA electron(positron)­proton collider and the DORIS synchrotron radiation source and their improvements. He reported results from the TESLA international project for a linear electron positron collider and spoke on future plans for the Tesla Test Facility.

All of CERN’s machines set new records in 1998. With a new extraction channel, a beam from the SPS synchrotron could be used for generating neutrinos for an experiment in the underground laboratory of Gran Sasso, Italy, 732 km away from CERN (November 1998).

Record run

J Dorfan of SLAC reported from the Stanford Linear Collider where a record 10 month run had just ended. Investigation of the neutron and proton spin structure continues in the fixed-target SLAC programme. For the future the B-factory based on the PEP II electron­positron collider will open a new physics programme.

The Relativistic Heavy-Ion Collider at Brookhaven, with 100 GeV per nucleon for heavy ions and 250 GeV for protons, is nearing completion, reported S Ozaki. The first experiments with colliding beams (gold ions) will be followed by investigations with polarized beams, beginning in the year 2000.

The Budker Institute of Nuclear Physics operates the VEPP-4 electron­positron collider at 5.5 GeV and a luminosity of 1032, according to A Skrinsky of Novosibirsk. Development continues for the VLEPP linear electron­proton collider. BINP takes an active part in the development of the electron­nucleus collider that is proposed at GSI in Darmstadt.

From Japan, with the operation of the KEKB asymmetric electron­positron collider (8 GeV electrons, 3.5 GeV positrons, design luminosity 1034) imminent, S Kurokawa described experiments for this storage ring and the K2K experiment on the oscillations of neutrinos generated by the 12 GeV beam from the KEK proton synchrotron and using the SuperKamiokande detector 250 km west of KEK.

Increased beam intensity

E Troyanov of IHEP reported the main recent results from the 70 GeV Serpukhov proton synchrotron and the status of the Accelerator Storage Complex (UNK). The U-70 accelerator is being upgraded, the ultimate goal being to increase the beam intensity to 5 x 1013 and to prepare the accelerator for an UNK injector. Despite a lack of funds, measures are being taken to maintain 21 km of UNK tunnel, and the manufacture and installation of equipment for the “warm” 600 GeV UNK proton synchrotron is under way.

A Temnykh of Cornell covered the Cornell Electron Storage Ring, which is operating as an electron­positron collider with 6 GeV beams. The available maximum luminosity is 6 x 1032. The replacement of copper cavities by superconducting ones and vacuum improvement will soon boost its luminosity to 1033.

Progress towards CERN’s LHC was reported by P Lebrun. The first full-scale prototype dipole has been built and successfully tested in cooperation with INFN of Italy. Short, straight sections of the ring and their quadrupoles have been designed in co-operation with CEA and CNRS of France. The first prototype magnets for the injection beamline have been designed and manufactured at Budker INP. Other elements of the LHC magnetic system are being designed in co-operation with Canadian, Japanese and US laboratories.

GSI Darmstadt’s Electron­Nucleus Collider project was discussed by K Blasche. Its main aim would be to investigate deep inelastic electron­nucleon and electron­nucleus scattering at collision energies of 10-30 GeV. The design luminosity is 1033 for electron­proton collisions and 4 x 1032 for collisions with uranium nuclei.

The beginning of work for the MUSES project for a radioactive ion Beam Factory at RIKEN, Japan, was reported by T Katayama. This involves four new accelerating facilities. One, a double storage ring, will be used as an ion­ion and electron­ion collider for ions of 1.5 GeV per nucleon and 2.5 GeV electrons. The calculated luminosity for ions of isotopes with a lifetime of 1 min is 1032.

A Kovalenko of JINR and Fermilab’s E Malamud discussed future projects, among them the Very Large Hadron Collider, with beam energies of 2 x 50 GeV using Nuclotron-type magnets. Progress for muon colliders was reviewed by R Palmer of Brookhaven.

S Mitsunobu of KEK and DESY’s D Proch and W Singer described the development of superconducting cavities for future linear colliders. Accelerating fields could reach 40 MV/m.

Linear colliders based on normal conducting cavities (for which the maximum accelerating field strength is 100 200 MV/m) were discussed by V Balakin of Budker INP.

For CERN’s CLIC collider with a maximum energy of 5 TeV and a luminosity of 1034-1035, reported by I Wilson, a new, potentially more effective and cheaper, method uses two-beam acceleration for generating radiofrequency power with the hope of achieving accelerating fields of 150 MV/m. The NLC, TESLA/SBLC and JLC collider projects also envisage gamma­ gamma and gamma­electron collisions. Photon colliders can appreciably increase the research potential of linear colliders for insignificant extra cost, according to V Telnov of BINP.

The message from the round-table discussion chaired by G Loew of SLAC was that linear colliders are promising tools for high-energy physics.

Another round-table discussion recommended that the Dubna experience should become a model for future conferences in the series, with a relatively small number of leading participants for talks and debates on future projects, and with promising young scientists being invited to present novel techniques and technologies.

Despite a serious economic crisis in Russia, the organization of the conference was assured, thanks to the support of INTAS, IUPAP, the Russian Foundation for Basic Research, the Ministry of Science and Technologies of the Russian Federation, the Ministry of Atomic Industry of the Russian Federation, some businessmen and sponsors from Dubna, and, finally, JINR, despite its own financial problems. Aeroflot proposed special tariffs.

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