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Pisa pushes new frontiers

24 July 2006

The island of Elba, off the coast of Tuscany, hosted the 10th Pisa meeting on frontier detectors, a quarter of a century since the meetings began. Giorgio Chiarelli reports.

Sur l’île d’Elbe, des physiciens tournés vers le futur

La dixième rencontre de “Pise” sur le thème Frontier Detectors for Fontier Physics (FD4FP) a eu lieu sur l’île d’Elbe du 21 au 27 mai. Quelque 300 participants étaient présents cette année et 200 contributions ont été sélectionnées. Les thèmes abordés allaient de la calorimétrie aux détecteurs à gaz en passant par les dispositifs à semi-conducteurs, l’électronique, l’identification des particules ou les appareils conçus pour l’astrophysique des particules et la cosmologie. Deux nouveautés étaient également au programme: une séance spéciale sur les expériences du Grand collisionneur de hadrons (LHC) et une table ronde sur les accélérateurs du futur. Des entreprises de haute technologie du monde entier ont également participé en exposant leurs produits et en présentant des exposés.

The Pisa meetings on Frontier Detectors for Frontier Physics (FD4FP) began 25 years ago as a small gathering in Tirrenia, near the INFN Pisa Laboratory. This year more than 300 participants from 21 countries attended the 10th in the series, held on Elba on 21-27 May. Lello Stefanini, chair of the FD4FP executive board, reminded the audience in his opening address that, after beginning in Pisa, the meeting moved to Castiglione della Pescaia in 1983 and 1986, and finally settled in La Biodola on Elba in 1989. This year it attracted about 200 selected contributions. As detector development and construction takes place in close collaboration with industries, hi-tech firms from all over the world displayed their products alongside presentations and direct interaction with researchers.

To mark the 10th meeting, there were two main modifications to the schedule. The first was a special session on experiments for the Large Hadron Collider (LHC) at CERN. Following an introduction by Michelangelo Mangano of CERN and John Carr of Centre de Physique des Particules de Marseille to the future of high-energy and astroparticle physics, a number of speakers described the main features and the status of the LHC detectors. After years of detector R&D and construction, four large devices are becoming reality and beginning to take data with cosmic rays in preparation for the real beams.

In a second innovation, day two of the meeting included a round table on strategies for future accelerators, chaired by Albrecht Wagner, chair of the International Committee for Future Accelerators and director of DESY. Fermilab’s Jim Strait showed how the laboratory is running the Tevatron while broadening both its neutrino programme (with the MINOS and NoVA experiments) and its effort on the R&D for a future International Linear Collider (ILC).

During the round table, Jos Engelen of CERN stressed the importance at CERN of R&D for the Compact Linear Collider (CLIC) and SuperLHC studies while keeping the main focus of the laboratory on the start-up and the exploitation of the physics capabilities of the long awaited proton-proton collider, the LHC. Barry Barish, director of the ILC Global Design Effort, outlined how a triadic approach – with facilities for neutrino physics, an exploratory high-energy frontier with proton-proton colliders and a precision high-energy frontier with e+e- colliders – would address most of the open problems in particle physics. He also showed how the efforts of a large community that is gathered to design a baseline ILC are making progress towards a Reference Design Report to be available by the end of 2006.

Atsuto Suzuki of KEK showed the impressive results from the KEK-B facility and progress with the Japan Proton Accelerator Research Complex. The multipurpose accelerator complex is on schedule to provide beams to the users by 2008. At the same time the Japanese community is fully involved in the R&D for the ILC to be ready either to participate in an early built ILC or to upgrade the KEK-B facility. Finally in the round table, Roberto Petrozio, INFN president and chair of the Funding Agencies for the Linear Collider (FALC) committee, presented the INFN’s strategies for future accelerators aimed mainly at e+e (low and high energy) colliders, high-intensity radioactive beams for nuclear physics, and the exploitation of hadron beams for medical applications. He clearly indicated how the synergy among different projects is key to the approach. As chair of FALC, Petrozio later reported on recent discussions aimed at harmonizing and optimizing the human and financial resources in high-energy physics in the near future.

A discussion ended the round-table session, with several questions and comments raised from the floor, mainly aimed at understanding how the field will be able to widen the support for its projects and fulfil its promises with the resources available. There was a consensus that a successful start-up of the LHC will be a testbed for the capability of the particle-physics community and might boost it to become bolder and seek even more ambitious goals.

The remaining sessions followed the established tradition, covering all aspects of design, development and running of detectors for high-energy physics. Topics ranged from calorimetry to gas detectors, from solid-state devices to electronics, from particle identification to devices designed for astroparticle physics and cosmology, in so many presentations that only a few aspects can be highlighted here.

Silicon represented the lion’s share among the contributions. Over the years, the use of this material has extended from tracking detectors to calorimetry and particle identification, because the only limitation seems to be our own imagination. What was once used to miniaturize particle detectors and make them more compact is now the base for large-scale devices, for example for trackers for the LHC experiments and for the Gamma-ray Large Area Space Telescope. The need for a further reduction in the amount of material used and the requirements of the next generation of colliders demand an even closer integration of electronics and detectors, so more groups are now involved in developing and understanding monolithic devices.

Moving away from planar devices, 3D silicon detectors, presented at the ninth FD4FP meeting, are now better understood and seem able to provide detectors that are almost free from dead zones. At the ninth meeting, Valery Saveliev of Obninsk State University proposed silicon photomultipliers (SiPM). The past three years have seen a number of groups developing detectors based on this original R&D concept, so it is not surprising that several contributions presented results on SiPM or on devices based on similar concepts that are now being built by several firms around the world.

Several contributions focused on detectors based on gas, showing that they have a future besides the LHC, both on the ground and in space. Richard Wigmans of Texas Tech University presented the results of the dual read-out calorimeter project, DREAM. The separate measurement of the electromagnetic and hadronic component of a hadron shower seems the best way to a precise determination of its energy. It will be interesting to see whether in the near future an experiment will translate this R&D into a full-scale detector.

The growing application of high-energy physics techniques in other fields of research (mainly, but not exclusively, in medicine and biology) was well described in a dedicated session of posters and presentations. Reports on the results of two field studies in archaeological sites, at the Aquileia port near Udine and at the Traiano and Claudio port near Rome Airport, showed an intriguing use of muons, detected by scintillating fibres, for underground mapping.

Three young participants received the 2006 FD4FP Young Physicist Award for their work and presentations. Nicola Cesca, who has a fellowship at the University of Ferrara reported on the semiconductor small-animal scanner, SiliPET; Bilge Demirkoz, a graduate student at Oxford University, presented the ATLAS Semiconductor Tracker; and Judith McCarron, a graduate student at Edinburgh University, presented tests and results of the hybrid photon detector for the ring imaging Cherenkov detector of the LHCb experiment for the LHC.

Further reading

For electronic versions of the presentations, or to view the webcast, which was broadcast live, see www.pi.infn.it/pm/2006.

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