Giorgio Brianti

The Large Hadron Collider (LHC) in the LEP tunnel

After the remarkable start-up of LEP, the installation of a Large Hadron Collider, LHC, in the LEP tunnel will open a new era for the High Energy Physics. This report summarizes the main LHC parameters and subsytems and describes the more recent studies and developments.

Design study of a superconducting dipole model magnet for the Large Hadron Collider

A design study of a high-field superconducting dipole magnet for the LHC (Large Hadron Collider) project has been carried out in cooperation between CERN and KEK. The objective is to develop a 1-m twin-aperture dipole model magnet based on double shell coil design with a fully symmetric split collaring structure. Development of superconducting cable with high keystone angle is a key technology to realize this magnet. The progress made in the design study and the development of the 1-m dipole model magnet are described.

LHC progress and status

The LHC is a superconducting collider to be installed in the LEP tunnel for high energy pp, Pb ions and ep collisions. An overall machine optimization, including a new lattice arrangement and an increased dipole aperture (56 mm), will be presented. The increased energy to field ratio is (0.81 TeV/T). Recent results from a magnet model with industrially produced coils assembled at CERN reached 10 T with a limited training and ultimately attained 10.5 T. Demonstrating that operational fields in excess of 9 T can be obtained. Results from previous models and a 10 m-long prototype will be given. In total seven of these prototypes are being constructed by industry. In December 1991, the CERN Council unanimously adopted a resolution stating that the LHC is the right machine for the future of CERN and requesting a final proposal in 1993, which is being actively prepared and is summarized in this report.<<ETX>>

Test results of a single aperture 10 tesla dipole model magnet for the Large Hadron Collider

A single aperture dipole magnet has been developed with a design magnetic field of 10 tesla by using Nb-Ti/Cu conductor to be operated at 1.8 K in pressurized super fluid helium, The magnet features double shell coil design by using high keystone Rutherford cable and compact non-magnetic steel collars to be adaptable in split/symmetric coil/collar design for twin aperture dipoles. A design central magnetic field of 10 tesla has been successfully achieved in excitation at 1.95 K in pressurized superfluid helium. Test results of the magnet with a summary of the design and fabrication are presented.

Experience with the CERN pp complex

In the CERN pp complex, antiprotons for collisions with protons or for direct use in experimental targets are provided over a very wide energy range, namely : pp collisions at S = 540 GeV in the SPS, pp collisions at S = 52 GeV in the ISR, ps down to a kinetic energy of 5 MeV from LEAR. This report gives an account of the experience gained so far, mainly in 1982, in actual physics runs in SPS and ISR, and during the commissioning of LEAR. The main novelty concerns an extended physics run of two months in the SPS, where a peak luminosity of 5.3×1028 cm-2 s-1 was reached and an integrated luminosity of 28 nb-2 or 2.80×1034 cm-2) was supplied to the two main experiments UA1 and UA2. Another very encouraging result was obtained in LEAR where p beams, extracted from the Antiproton Accumulator at 3.5 GeV/c and decelerated in the PS to 0.6 GeV/c, were successfully injected and captured in LEAR, decelerated to 50 MeV kinetic energy and stochastically cooled. The first physics run will take place this summer. The ISR have exploited their excellent vacuum and reliability by storing antiprotons for physics runs of up to two weeks. There have been 10 physics runs to date and the peak luminosity achieved was 2.5×1028 cm-2 s-1.

A second collider in the CERN LEP tunnel for pp (pp) and ep physics in the multitev energy range

The LEP collider at present under construction at CERN will provide e9 e9 collisions in four large detectors, initially at a centre of mass energy of 110 GeV to be gradually increased to ˜ 200 GeV by means of superconducting r.f. cavities. First beam is planned for the end of 1988. The tunnel has a circumference of ˜ 27 km and can house a second collider on top of the present one, designated as Large Hadron Collider (LHC)1 (Figs. 1 and 2).

A Strong Focussing Ring, as Beam Stretcher for Synchro-Cyclotrons

The possibility of injecting the Synchro-Cyclotron extracted proton beam into a strong focussing ring called CYBEST, is investigated. It is seen that pion beams produced in internal targets of such a device show some advantages with respect to present Synchro-Cyclotron beams. More detailed studies are needed however for final judgement. CYBEST is realizable if a sufficiently fast extraction from the Synchro-Cyclotron could be obtained. The magnetic structure is simple but occupies a large area and the required aperture is also relatively large.