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The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

The Large Electron-Positron Collider (LEP) was the largest lepton collider ever built, and gave high precision measurements of the W and Z particles. LEP was commissioned in 1989 and shut down in 2000, to leave room for the LHC. In conjunction with an energy upgrade, new, superconducting, final- focus (low-$\beta$) quadrupole magnets were built. The new magnets resembled much those built for the ISR luminosity upgrade, i.e., the coils were wound with a single rectangular wire. They operated at 4.5 K in a cryostat especially developed to fit into the limited space available in the shield placed in front of the experiment.

The Tevatron was the first synchrotron built with superconducting magnets and paved the way for large scale applications of superconductivity. It was installed in the tunnel at Fermi National Accelerator Laboratory, Batavia, Illinois (USA). It operated reliably from 1983 to 2011, producing protons and anti-protons with energies up to 980 GeV. Besides the technology prowess, the Tevatron enabled the discovery of the top quark in 1995, the last fermion of the Standard Model to be observed.

These documents represent the filing system of Christopher Llewellyn Smith during his period as Director-General of CERN. They cover all aspects of CERN's activities, and include: relations with the Delegations relations with Administrative Sector, Accelerator and Technology Sector, and Computing and Research Sector minutes of Directorate, Management Board meetings, etc... minutes of scientific committees and other committees meetings conferences correspondence documents concerning official visits personnel matters concerning appeals, early retirements, policy, recruitment... * DG working files