The CERN Cryogenic Test Facility for the Atlas Barrel Toroid Magnets

The superconducting magnet system of the ATLAS detector will consist of a central solenoid, two end-cap toroidal magnets (ECT) and the barrel toroid magnet (BT) made of eight coils symmetrically placed around the central axis of the detector. The magnets will be tested individually in a 5000 m2 experimental area prior to their final installation at an underground cavern of the LHC Collider. For the BT magnets, a dedicated cryogenic test facility has been designed which is currently under the construction and commissioning phase. A liquid nitrogen pre-cooling unit and a 1200 [email protected] refrigerator will allow flexible operating conditions via a rather complex distribution and transfer line system. Flow of two-phase helium for cooling the coils is provided by centrifugal pumps immersed in a saturated liquid helium bath. The integration of the pumps in an existing cryostat required the adoption of novel mechanical solutions. Tests conducted permitted the validation of the technical design of the cryostat and its instrumentation. The characteristics of one pump were measured and pressure rise of 300 mbar at nominal flow of 80 g/s confirmed the specifications

Cryogenics for CERN experiments: past, present and future

Use of cryogenics at CERN was originated (in the 1960s) by bubble chambers and the associated s.c. solenoids. Complex cryoplants were installed to provide cooling at LH2 and LHe temperatures. Continuity (in the 1970s) in He cryogenics for experiments was provided by spectrometer magnets for fixed target physics of the SPS accelerator. More recently (in the 1980s), large "particle-transparent" s.c. solenoids for collider experiments (LEP) have been built demanding new cryoplants. The LHC experiments (in the 2000s) will continue the tradition with s.c. dipoles (ALICE and LHCb), solenoids (CMS, ATLAS) and toroids (ATLAS) of unusual size. Cryogenics for experiments using noble liquids follows the same trend since the development (in the 1970s) of the first shower LAr detectors. A LKr calorimeter (about 10 m3) will be operated in 1996 and the ATLAS experiment foresees a set of three huge LAr calorimeters (almost 90 m3 total volume of liquid) to be installed underground

Proton Unbound States in T=3/2 and T=2 Nuclei and the Reaction Rates for Sequential Two-proton Capture Reactions in the rp-Process

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Efficacité de l’interprofessionnalité : des preuves, un défi… [Efficacy of interprofessionnality : evidence and challenges]

Skillmix is often proposed as a measure to address the growing needs of an aging population with its expected increase in chronic diseases. This article reports on a symposium on interprofessional collaboration which took place in the canton of Valais in Switzerland. Reviews of the literature on interprofessional collaboration show evidence in favor of the effectiveness of having interactions between physicians, nurses, pharmacists and physiotherapists. A critical analysis of different forms of coordinated care within family medicine supports the effectiveness of these approaches. However, these approaches now need to be tested in Switzerland