ATLAS electromagnetic calorimeter Fruitful collaboration of the IN2P3, the CERN and the CEA/DAPNIA, the whole calorimeter modules have been integrated in the cryostat in 2003.
A perfect understanding of detection instruments is essential for the physical interpretation of experimental data. Therefore, DAPNIA physicists and Sédi engineers and technicians work together very closely during the design phases as well as during calibration testing. These close links, which constitute a source of motivation for technical staff, are also a guarantee of the quality and performance of the instruments. However, the respective responsibilities of the physics and instrumentation services are clearly defined and the project organization established several years ago by the Department identifies the role of different players and ensures optimized management of resources, which can be shared between several experiments. The departmental organization matrix thus allows Sédi to work on several projects, focusing on each the skills and critical size to enable the department to make a significant contribution to international collaborative projects.
The preparation of experiments on the Large Hadron Collider (LHC) at CERN has been the dominant activity within the service for the last three years, with a significant commitment to Atlas (manufacture and integration in collaboration with IN2P3 of the liquid argon electromagnetic calorimeter modules,development of the Tower Builder Boards for the Level-1 trigger, development in collaboration with IN2P3 of Hamac ASICs) and to CMS (development and implementation of the optoelectronic monitoring system for the 100,000 crystals in the experiment, design and development of the Selective Readout Processor, which allows a realtime reduction in the flow of data towards the acquisition system). Within Alice, Sédi is contributing alongside other institutes to the manufacture of the cathode pad chambers of the dimuon spectrometer. Sédi’s involvement in the LHC programs also includes software, with a significant contribution to the conditional database of the Atlas muon spectrometer. The creation of the world’s largest camera, the Megacam, is one of the successes of recent years. Sédi was the chief contractor in the project, and was responsible for integration of the focal plane consisting of 40 CCD sensors covering a 1°×1° field with 360 million pixels, development of the associated electronics, and integration and commissioning of the instrument. Research and development on the Micromegas gas detector culminated in the use of the detector in a number of physics experiments at CERN. These were the Compass experiments (design and production of 12 detection planes of 400 x 400 mm2 each, bringing together 12000 electronics channels fitted with SFE16, a low noise ASIC designed and developed by Sédi’s microelectronics group), NA48-Kabes (production of three beam spectrometers operating in a hostile environment with very tight requirements in terms of spatial and temporal resolution) and Cast (development of an X-ray detector with x-y reading and a very low energy threshold). The Edelweiss project installed in the underground laboratory at Modane has also seen major technical and scientific advances with a data acquisition system combining three bolometers integrated by Sédi. Currently, the service is heavily involved in phase II of the experiment, working both on the bolometric detectors and on the acquisition system and mechanical integration of the experiment. The Antares project, which relates to the development of an underwater neutrino observatory, is another of the service’s major commitments. Sédi is responsible for the production of optical modules, the supply of cables linking the submarine to the surface and many electronics developments (ARS front-end ASIC, capture and switching boards, embedded software). A number of experiments being carried out at Ganil are using detectors designed and produced by Sédi. The secondary emission detectors of the Vamos spectrometer offer increased performance in terms of spatial and temporal resolution. Similarly the Mate ASIC designed for the three types of detectors in the Must spectrometer signifi cantly improves its spectroscopic properties. The service has been involved in on-board astrophysics experiments through Herschel (design and development of the subsystem control unit for Spire) and Glast (supply of crystal detector elements for the calibration tests).
During the next three years, the service will continue to be involved at a high level with the detectors on the LHC in the three experiments to which we are contributing. The share of mechanics will however tend to give way to development and production in the fields of electronics and IT. The physics of neutrinos will be a growing area of activity both within the lines of detection of Antares, the immersion of which is planned during this period, and within new projects at reactors (Double-Chooz) and at Japanese accelerators. Bolometric detectors for the physics of dark matter (Edelweiss II) and cosmic background radiation (Olimpo) also constitute an important part of our activity. Finally, involvement in the JWST infrared imaging device will constitute our principal contribution to on-board experiments.
Last update : 05/22 2018 (558)