CERN1's Large Electron Positron Collider, LEP, started up for physics right on time on the 2 May, a considerable achievement for the Laboratory's technicians and engineers who have worked flat out to put right the damage caused by an act of sabotage earlier in the year.
The sabotage was discovered on Monday the 13th February. About 1300 electronic modules had been removed from the control system of two of the Laboratory's accelerators, the Proton Synchrotron (PS), and the PS Booster, which form part of the chain which ends up with LEP. All the missing equipment was soon discovered, undamaged, hidden about the laboratory, and the painstaking task of reassembly began. In addition to the reinstallation of 1300 modules, thousands of cables had to be reconnected. It is a great credit to the staff involved and a reflection of their motivation that CERN's 1995 physics programme was able to start on time. As a result of some rescheduling of operations, the net loss in the Laboratory's physics activities will be only one week of the antiproton programme, which got under way on the 21st April and is already in full swing.
The countdown to collisions in LEP began when the four experiments, ALEPH, DELPHI, L3, and OPAL closed up their detectors on Saturday 22nd April. The first beam of 20GeV positrons was injected at 4pm on the same day, and by 7pm, LEP engineers had already retuned the machine after the long winter shutdown, allowing positrons to circulate the full 27km of the LEP ring. Electron beams were injected and circulated overnight, and by Monday lunchtime, the first beam of 1995 was accelerated to the full energy of 45GeV. The rest of the week was spent commissioning new equipment designed to bring a greater collision rate than ever before, and the beams were finally brought into collision at 11pm on 2 May.
1995 promises to be an exciting year for CERN. The CP LEAR experiment is already collecting good quality data with antiprotons, hoping to understand the mechanism, known as charge-parity (CP) violation, which has lead to the domination of matter over antimatter in the Universe. The two experiments, CHORUS and NOMAD, devoted to the elusive neutrino particle are hoping to shed some light on the Universe's dark matter. CHORUS will continue its harvest of data, whilst NOMAD will start routine data taking after preliminary runs in 1994. Finally LEP itself is set for another record breaking year, with physicists confidently expecting more data than ever before.