[en] Published in summary form only. German version published in Technische Rundschau Sulzer (1991) (no.4) p. 18-20

[en] The roles of CERN and the ECFA in the planning of LEP are stated and a brief assessment is given of the work to be done in further technological studies, in preparing the experimental programme, and to ensure the best use possible can be made of the LEP facility. (W.D.L.)

[en] This report consists of a collection of documents produced by a Study Group on Large Electron-Positron Storage Rings (LEP). The reactions of interest in the weak, electromagnetic and strong interactions are discussed. The technical feasibility of the relevant experiments is investigated by attempting, in each case, the design of an experimental set-up. Event rates are estimated using currently prevailing theoretical models and by extrapolation of results at present accelerators. A number of technical reports previously issued by members of the LEP Design Study Group are included as appendices. (author)

[en] At the end of 1992, LEP completed its fourth year of operation, producing more than 28 inverse picobarns of integrated luminosity in each of the four experiments and a total of three million hadronic Z⁰s. For the first time the machine operated for physics with a new high-tune optics producing the smaller transverse emittance eventually needed for future operation at higher energy. As well as gaining valuable experience with this optics the luminosity lifetime could be improved by using wigglers to control the evolution of beam emittance during a run. In addition, the so-called 8-bunch open-quotes pretzelclose quotes scheme was commissioned, allowing the number of bunches per beam to be increased from four to eight towards the end of the year. Present performance limitations are discussed and future plans for increasing both the energy and luminosity are described

[en] Synchrotron Radiation interferences between small dipoles in the very low (visible) frequency range have been studied at the LEP diagnostic mini-wiggler. Their understanding allowed a substantial brightness gain by adequate layout modifications. The phenomenon is described analytically in terms of time coherence effects. This serves as a basis for further detailed numerical simulations of the experiment by means of stepwise ray-tracing, and allows precise interpretation of the spectral, polarization and intensity measurements collected at LEP. It also provides guidelines for SR diagnostic at injection energy in LHC

[en] The spirit behind LEP phase 1 is to achieve a first beam as fast as possible with as little equipment as necessary but without a guaranteed luminosity. The philosophy of a 'stripped down' version of LEP is different from the '1/6 stage' in the Pink Book where the construction of the complete machine including the whole infrastructure was envisaged but only 1/6 of the r.f. was to be installed. This would have implied too long a time until the turn on of a first beam. Hence a big effort is being made to reduce the number of components and their complexity to achieve 50 GeV per beam in 1986 with an essentially constant budget of CERN. However, it is essential at the same time not to compromise any of the future development possibilities. (Auth.)

No abstract available

[en] The optics for physics operation in LEP was changed from 60 degree to 90 degree at the start of 1992 with a view to improved Z⁰ production, preparation for future operation at higher energies and the use of the same optics in machine developments. The developments included running LEP with twice the number of bunches and using resonant depolarisation for energy calibration. Perturbation to steady operation was felt at the start of the year but was soon overcome as the benefits of smaller emittances were realised. The peak luminosity increased to 1.15 10³¹ and the luminosity lifetime improved. New operational software halved the time taken between dumping one coast and the start of data taking on the next. The 8+8 bunch operation was introduced as routine operation for the last month. Overall, there was an increase in integrated luminosity from 17.6 inverse picobarns per experiment in 1991 to 28.6 in 1992. Along with improvements in detector efficiency, almost 3 million hadronic Z⁰s were recorded by the four experiments, an increase from 1.27 million in 1991

[en] This paper describe the status of the LEP machines and of the four LEP detectors, up to and including the LEP pilot run which took place from August 13 to 18, 1989

[en] Published in summary form only