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such studies will help our under­ BROOKHAVEN standing of subnuclear particles. CERN Said Lee, "The progress of physics New US - Japanese depends on young physicists encore opening up new frontiers. The Physics Centre RIKEN - Brookhaven Research Center will be dedicated to the t the end of 1996, the beam nurturing of a new generation of Acirculating in CERN's LEAR low recent decision by the Japanese scientists who can meet the chal­ energy antiproton ring was A Parliament paves the way for the lenge that will be created by RHIC." ceremonially dumped, marking the Japanese Institute of Physical and RIKEN, a multidisciplinary lab like end of an era which began in 1980 Chemical Research (RIKEN) to found Brookhaven, is located north of when the first circulated the RIKEN Research Center at Tokyo and is supported by the in CERN's specially-built Antiproton Brookhaven with $2 million in funding Japanese Science & Technology Accumulator. in 1997, an amount that is expected Agency. With the accomplishments of these to grow in future years. The new Center's research will years now part of 20th-century T.D. Lee, who won the 1957 Nobel relate entirely to RHIC, and does not science history, for the future CERN Physics Prize for work done while involve other Brookhaven facilities. is building a new antiproton source - visiting Brookhaven in 1956 and is the , AD - to now a professor of physics at cater for a new range of physics Columbia, has been named the experiments. Center's first director. The invention of The Center will host close to 30 by at CERN scientists each year, including made it possible to -produce postdoctoral and five-year fellows antiprotons. With these beam cooling and visiting scientists. Its research techniques available, focus will begin with theoretical proposed transforming CERN's then physics but will eventually expand to new SPS into a include experimental studies. high energy proton-antiproton collider

With Brookhaven the home of the T.D. Lee is first director of the new RIKEN US- and building big experiments to Relativistic Heavy Collider Japanese Research Center at Brookhaven. search for the W and Z carrier (RHIC), to begin operation in 1999, particles of the weak nuclear force. the new Center's research will relate With CERN anxious to spread its to the experiments that will be research wings, the message fell on performed at RHIC by scientists from fertile ground. In 1983, just three 19 countries. years after CERN accelerated its first RHIC's main purpose is to collide antiprotons in the specially built heavy nuclei such as gold at high , the W and Z energy to continue the search for the were in the bag and the following long-awaited quark-gluon , year Rubbia and van der Meer were the precursor of conventional nuclear awarded their Nobel Prize. as the Universe cooled in the While the W and Z were the big wake of the Big Bang. prizes, this was not the only new But RHIC took on an additional, physics that antiprotons could complementary mission in 1995, provide, and alongside the big when RIKEN agreed to contribute machines the LEAR ring decelerated $20 million to equip RHIC for the the particles for another range of study of the world's highest-energy physics. LEAR hit the headlines in spin-polarized protons (November 1995 when a team working with a 1995, page 1). Scientists hope that special gas jet target at the Jetset

CERN Courier, May 1997 1 Around the Laboratories

For the future CERN is building a new antiproton source - the antiproton decelerator, AD - to cater for a new range of physics experiments. The AD will be built using the former (AC) ring, commissioned in 1987 to supplement the original Antiproton Accumulator and serve a new experimental area inside the ring's four straight sections, two of 28m and two of 15m, linked by densely packed magnet arcs.

experiment saw the world's first atoms of (January 1996, page 1). The discovery of atomic antimatter made headlines across the world, but the big scientific question remained unanswered - does antimatter behave in exactly the same way as matter? Subtle differences between the behaviour of matter and antimatter could have significant implications for our understanding of how the Universe as we know it emerged from the Big Bang. To answer this question, LEAR would no longer be available, its destiny having already been decided. LEAR will now be converted into the LEIR ion ring to prepare beams of lead and other heavy nuclei prior to injection into CERN's new LHC collider, to come into operation in 2005. The new AD antiproton source will be built using the former Antiproton protons using a special production nal bunches of 5 x 107 antiprotons Collector (AC) ring, commissioned in target at the PS proton synchrotron, should survive. At this stage, the 1987 to supplement the original AA using the latest improvements in antiprotons will be ready for ejection and relieve it of the onerous task of beam handling techniques. into the waiting beamlines serving precooling the injected antiproton Initial stochastic cooling will reduce the experiments. beam prior to stacking in the AA. momentum spreads to just 0.1%, With the exploration of In this way CERN's antiproton levels after which the antiprotons will be or similar anti-atoms high on the were boosted tenfold. decelerated to 2 GeV/c momenta and agenda, the new ATHENA and The AC/AD transformation cost of the resultant beam blow-up ATRAP experiments will use some 7 million Swiss francs plus compensated by further stochastic magnetic trapping techniques to some external manpower will be cooling. create and capture more than 1000 provided by special contributions The existing 1.6 MHz radio- neutral atoms of antihydrogen per from several countries, including frequency system to decelerate the hour, and using precision laser Denmark, Germany, Italy, Japan, antiprotons will be modified to cover techniques for hyper-accurate Poland and the US. a frequency range of 0.5 -1.6 MHz, . The 'ring' has four straight sections, while the system used to rotate the Another experiment will be by a two of 28m and two of 15m, linked by particle bunches has to be moved to Japanese-European collaboration to densely packed magnet arcs. The AA free space for the new electron continue the exploration of and AC were concentric, with the AC cooling system. antiprotonic atoms, where a LEAR on the outside. Dismantling the AA When deceleration has reached experiment by a Tokyo/Okazaki/ ring liberates space for a new 300 MeV/c momenta, electron Munich/Budapest/CERN team experimental area enclosed by the cooling becomes the order of the discovered that AD. day. Using the cooler previously used can be extraordinarily stable For the AD, antiprotons, selected at at LEAR, momenta will finally reach a (December 1994, page 18). Earlier 3.57 GeV/c in the traditional way, will floor at 100 MeV/c. At these ener­ this year, the Japanese Ministry of continue to be produced by 26 GeV gies, an estimated 25% of the origi­ Education, Science, Sports and

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The COMPASS spectrometer at CERN's SPS proton synchrotron will combine a common core with interchangeable elements for proton (hadron) and muon beams. The common equipment consists of ring-imaging Cerenkov counters, RICH, electromagnetic and hadronic calorimeters, ECAL and HCAL, muon filters, and the spectrometer magnet SM2. The main difference between the two configurations will be the target system and upstream spectrometer magnet, SM1-H.

Culture (Monbusho) announced this HCALI muon setup project had been selected as an HCAL2 important ongoing project. The AD construction schedule sees I the new ring being commissioned in ll|poi torgeiiu RICH 2 I 1998 and ready to supply its first M antiprotons in 1999. | 01 t t \ ECAL2 {A-wali 2 ECAL1 u-wai! 1

hadron setup

Set a course for the future showed to be quarks. A later experi­ in the COMPASS hadron beam ment conducted by the European programme too. In what is likely to be ith the closure of the Omega Muon Collaboration, EMC, at CERN experimentally the most challenging Wspectrometer (March, page 2) in the mid 1980s showed that these part of the programme, charmed still fresh in people's minds, CERN quarks carry only a small fraction of hadron decays producing a pair of has ensured a future for the multi­ the nucleon's spin. The SMC, with its leptons or a lepton and another purpose spectrometer concept with high quality polarized target, took hadron will be studied. This will probe initial approval of the COMPASS over from the EMC, and has gone as the internal structure of charmed programme. far as it can in quantifying this effect. mesons, and investigate the COMPASS, which stands for Current thinking points to gluons as transitions from heavy to light quarks Common Muon and Proton contributing to the nucleon's spin, in heavy hadron decays. Further Apparatus for Structure and and this is one of the ideas ahead, COMPASS plans to search Spectroscopy, will physically take the COMPASS will put to the test. for baryons containing two charmed place of the Spin Muon Collabora­ By looking for charmed mesons quarks, extending the currently tion, SMC, apparatus in CERN's high emerging from deep inelastic known baryon spectrum. intensity muon beam (January, scattering events, COMPASS will In the shorter term, the spectro­ page 2). Its initial physics aims will be probe the gluonic content of the scopy programme will address to continue the work of SMC into nucleus. This is because charmed another long standing question. It will nucleon structure, and to study in particles are mainly produced when a look for so-called exotic particles detail the hadron spectrum. For this virtual radiated by the incident made up of quarks and gluons - latter task, the muon beamline will be muon combines with a gluon from the particles such as glueballs, com­ modified to transport hadrons with target nucleon. posed only of gluons, quark-gluon energies up to 300 GeV as well as This method has been used in the hybrids, and quark-antiquark combi­ muons. past by the EMC to measure the nations which do not fit into existing Deep inelastic scattering momentum distribution of gluons in meson multiplets. The COMPASS experiments in which a high energy the nucleon. COMPASS will use a experiments will complement studies projectile scatters from a quark inside polarized target to probe the gluon recently completed at CERN's LEAR a nucleon were pioneered at SLAC, spin. By measuring charm production Low Energy Antiproton Ring, where Stanford, in the 1960s. These in deep inelastic scattering, new evidence for glueballs has been experiments demonstrated that COMPASS aims to provide the collected by the Crystal Barrel nucleons are made up of small definitive answer to a question which detector (October 1996, page 4). pointlike objects, which subsequent has been troubling physicists for over With its unusual mixture of muon studies using beams at a decade. and proton physics, COMPASS has CERN's bubble chamber Charmed particles play a major role attracted researchers with a diverse

4 CERN Courier, May 1997 Around the Laboratories

range of backgrounds. The core of in widespread use as insertion the SMC collaboration brings two FERMILAB devices - wigglers and undulators - decades of muon physics in synchrotron radiation sources and experience, whilst researchers from Permanent magnets free electron lasers: several facilities facilities as varied as LEAR and the and the Antiproton use ten or more, each up to 4.5 m in Omega spectrometer, both recently length.) closed, will carry on their studies with Recycler Ring Fermilab is also building permanent COMPASS. magnets for the newly approved But this disparity in experimental he Fermilab Main Injector project Antiproton Recycler Ring, an background disguises a great Tand the Tevatron luminosity important addition to the Fermilab similarity in physics goals. Although upgrades made a major step forward accelerator complex and a key factor their methods were different, February 20 with the successful first in the rising luminosity of the COMPASS members hailing from operation of the permanent magnet 8 Tevatron. LEAR, Omega, and the SMC have all GeV line. The achievement marks Fermilab's permanent magnets use been involved in studying the the first large-scale use of permanent strontium ferrite, an inexpensive structure of hadrons, and COMPASS magnets for high-energy commercially available material used is a logical place for them to come accelerators*, and helps establish mainly for automotive and consumer together. permanent magnets as a cost-saving applications. (The average new The programme foreseen for and effective accelerator technology. automobile uses about 10 kg of the COMPASS is to build a state-of-the- The 8 GeV line will connect stuff.) art spectrometer capable of handling Fermilab's new Main Injector to the A steel pole tip shapes the up to 2x108 particles per two-second Fermilab Booster, and is the first- , in a "hybrid" spill from CERN's SPS Super Proton commissioned component of the configuration pioneered by Klaus Synchrotron. This will be ready by Main Injector project. Halbach. This scheme allows an 1999. An initial five-year period of (*However permanent magnets are extremely precise magnetic field running is foreseen, after which the progress made will determine any future programme. With COMPASS and the recently approved AD Antiproton Decelerator (page 1) both set to start physics after the LEP Large Electron collider switches off, CERN's period of waiting for the LHC looks set to be full of new physics.

Fermilab recently operated a new 8 GeV beamline using permanent magnets. The line will connect Fermilab's new Main Injector to the Fermilab Booster, and is the first-commis­ sioned component of the Main Injector project. The achievement marks the first large-scale use of permanent magnets for high-energy accelerators.

CERN Courier, May 1997 5