For more than 20 years, solid niobium has had the monopoly on high-gradient applications of superconducting radio frequency (SRF) cavities for particle accelerators. But it will soon have reached its limits. It was only recently that A. Gurevich, a theoretician from Florida State University, put forward a theory explaining the reasons behind niobium's success and a way of breaking its monopoly. Until now, this theoretical model had never been experimentally demonstrated. This has now changed for a collaborative project between IRFU (Saclay) and INAC (Grenoble) has just made this vital step towards new acceleration technology.
Work on a new clean room, begun in July 2007 at the Saclay accelerator platform, has just been completed. The new clean room will be officially opened on 24 November 2009 and will replace the chemical facilities and clean room of IRFU's Accelerators, Cryogenics and Magnetism Division (SACM) located at L'Orme, which could no longer undergo all the improvements required to keep pace with current development work. A hall in building 124 (previously the Saturne laboratory) has therefore been renovated to accommodate the future facilities and equipment compatible with future accelerator research requirements and collaborative projects with industrial partners interested in the control of superconducting cavity systems.
Engineers and physicists from IRFU have successfully assembled and commissioned three large chambers designed to reconstruct charged particle tracks. The chambers will characterize the neutrino beam used in the T2K (Tokai to Kamiokande) experiment. They are the first large Time Projection Chambers (TPCs) to be equipped with micromesh gas detectors (Micromegas). The chambers have a very large sensitive area (nearly 9m²) and a correspondingly high number of electronic channels (124,000). IRFU built the entire detection system of the three TPCs, comprising 72 Micromegas detectors and all the front-end electronics. Engineers from SEDI, a department specialised in detector, electronics and information technology, specially designed a new chip called AFTER and two printed circuit boards for sending digitised signals to the acquisition system via an array of 72 gigabit optical links. The three chambers were tested with a particle beam at TRIUMF in Canada and have been installed in JPARC (Tokai, Japan) at the end of 2009.
The first beam and cosmic ray tests demonstrated that tracks could be reconstructed with the required degree of precision. This achievement represents a major step forward in the construction of a vital detector for the T2K experiment.
The TPC are now detecting tracks produced by neutrino interaction in the near detector of T2K and provide superior information to measure the momentum and to identify these particles.
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Dernière mise à jour : Jan 11th, 2024
