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LEP Experiments Take Shape LEP experiments take shape Excavation of the 27 kilometre the LEP Experiments Committee, at work in Shanghai cutting and tunnel and vast underground cav­ which carefully monitors the pro­ polishing the BGO crystals for the erns for CERN's new LEP electron- gress of these projects. L3 electromagnetic calorimeter positron collider is forging ahead, One impressive aspect of the before sending them to CERN for and equipment for the machine is work is the development of inge­ acceptance tests. arriving on the site in increasing nious tooling, often using sophis­ After apologizing for having no quantities ready to attack the huge ticated techniques, to facilitate video to show, ALEPH spokesman task of installation (see April issue, construction and assembly of the Jack Steinberger stressed the diffi­ page 1). detector components. culties of fashioning an electro­ At about the same time that LEP For L3, spokesman Sam Ting magnetic calorimeter with its acre construction work began at CERN described how assembly of the and a half (6000 square metres) in 1983, physicists from some huge 7000-ton magnet to surround of wire planes containing hundred research centres through­ the detector continues to make 750 000 wires and millions of con­ out the world began gearing up satisfactory progress with comple­ nections. for the detailed design, construc­ tion of coil segments at CERN Meanwhile other parts of the tion and testing of the millions of keeping step with the supply of detector are coming together components for the four big detec­ steel from the Soviet Union. Pro­ smoothly. Winding of the super­ tors - ALEPH, DELPHI, L3 and duction lines are being set up for conducting magnet will soon get OPAL - which will study LEP's the high precision drift chamber underway at Saclay in France, electron-positron collisions. system to pinpoint muons inside while sectors of the big Time Pro­ (For a detailed description of the magnet. jection Chamber to track particles these four experiments, see The first modules of the hadron inside the solenoid should soon July/August 1984 issue, page 227 calorimeter, using uranium supplied make their appearance at CERN. (DELPHI), September 1984 issue, by the Soviet Union, are at the Also starting is the huge task of page 269 (ALEPH), November Swiss Federal Institute for Reactor installing the thousands of stream­ 1984 issue, page 375 (OPAL), and Research, EIR. er tubes of the hadron calorimeter March 1985 issue, page 47 for A Ting video showed French inside the magnet return yoke. L3.) numerically-controlled machines DELPHI spokesman Ugo Amaldi Three years later, preparations for these four mammoth experi­ ments are well advanced. The ma­ jor aim is to be ready to intercept LEP's first colliding beams towards the end of 1988, which means that some less essential detection subsystems are being left for later. These projects require inter­ national collaboration on a scale unprecedented in a field of science already renowned for its ability to bring together scientists from dif­ ferent countries. Progress was highlighted at a recent meeting of The experiments for the LEP electron-positron collider being built at CERN involve together physicists from some hundred research institutes all over the world. Here a consignment of equipment for the L3 experiment arrives at CERN from the Soviet Union. (Photo CERN 226.2.86) CERN Courier, May 1986 1 related how the iron for the yoke DELPHI'S prototype Ring Imaging tract from the difficulties of con­ of the magnet barrel is making the Cherenkov (RICH), enabling the structing a huge detector by a long journey from Leningrad to final design to be firmed up. Spe­ widely scattered collaboration to CERN by boat, barge and road cial tooling has been developed a strict timescale. through Rotterdam and Strasbourg. for the slotted High Density Projec­ Spokesman Aldo Michelini des­ Winding of the superconducting tion Chamber of DELPHI'S electro­ cribed how all components for the solenoid should soon start at the magnetic calorimeter. magnet should be ready later this Rutherford Appleton Laboratory The OPAL experiment prefers year, and how the 'clean room' is in the UK. to use conventional technology being got ready at CERN for as­ Useful results are coming in from throughout, but this does not de­ sembly of the central detector jet chamber. It is hoped to operate this part of the detector for about a year prior to LEP's first particles. Construction work for other parts of the detector is well ad­ vanced, while simultaneously pro­ totype tests continue for the inner portions of the detector and for the electromagnetic presampler to be fitted between the solenoid and the surrounding lead glass of the electromagnetic calorimeter. 'The 21st century seems to have arrived', remarked one observer at the meeting. Ingenious tooling has been developed to facilitate the construction of the often complex modules for the different LEP experiments. Here is the machine which glues lead wire into ribbons for the High Density Projection Chamber of the DELPHI electromagnetic calorimeter. These ribbons are bent into 'accordions' by another machine, built by Pietro Negri in Milan. (Photo CERN 11.1.86) 2 CERN Courier, May 1986 .
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