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This paper contains a summary of the results of the magnetic and mechanical alignment tests performed at CERN on the first 111 arc Short Straight Sections. These include the mechanical axis of the Cold Bore Tube at room temperature, the magnetic axis of main quadrupoles and correctors at both room and cryogenic temperature, and the field direction of the main quadrupoles. The measurements show that the quality of the assemblies is generally within the requirements for the machine. [ABSTRACT FROM AUTHOR]

The Short Straight Section (SSS) for the Large Hadron Collider arcs, containing in a common cryostat the lattice quadrupoles and correction magnets, have now entered series production. The foremost features of the lattice quadrupole magnets are a two-in-one structure containing two 56 mm aperture, two-layers coils wound from 15.1 mm wide NbTi cables, enclosed by the stainless steel collars and ferromagnetic yoke, and inserted into the inertia tube. Systematic cryogenic tests are performed at CERN in order to qualify these magnets with respect to their cryogenic and electrical integrity, the quench performance and the field quality in all operating conditions. This paper reports the main results obtained during tests and measurements in superfluid helium. The electrical characteristics, the insulation measurements and the quench performance are compared to the specifications and expected performances for these magnets. The field in the main quadrupole is measured using three independent systems: 10-m long twin rotating coils, an automatic scanner, and single stretched wire. A particular emphasis is given to the integrated transfer function which has a spread of around 12 units rms in the production and is a critical issue. The dodecapole harmonic component, which required trimming through a change in coil shims, is also discussed. Finally, the magnetic axis measurements at room temperature and at 1.9 K, providing the nominal vertical shift for installation are reported. [ABSTRACT FROM AUTHOR]

The detailed shape of the 15 m long superconducting LHC dipole cold mass is of high importance as it determines three key parameters: the beam aperture, nominally of the order of 10 beam standard deviations; the connectivity of the beam- and technical lines between magnets; the transverse position of nonlinear correctors mounted on the dipole ends. An offset of the latter produces unwanted beam dynamics perturbations. The tolerances are in the order of mm over the length of the magnet. The natural flexibility of the dipole and its mechanical structure allow deformations during handling and transportation which exceed the tolerances. This paper presents the observed deformations of the geometry during handling and various operations at CERN, deformations which are interpreted thanks to a simple mechanical model. These observations have led to a strategy of dipole geometry control at CERN, based on adjustment of the position of its central support (the dipole is supported at three positions, horizontally and vertically) to recover individually or statistically their original shape as manufactured. The implementation of this strategy is discussed, with the goal of finding a compromise between conflicting requirements: quality of the dipole geometry, available resources for corrective actions and magnet installation strategy whereby the geometry tolerances depend on the final magnet position in the machine. [ABSTRACT FROM AUTHOR]

A reel-to reel MOCVD system has been developed for a fast and economic process to get high quality YBCO coated conductor tapes. Several oxides buffer layer sequences (based on YSZ, CeO[sub 2], Y[sub 2]O[sub 3] …) were then grown epitaxially on two kinds of tape. Effective stacking for MOCVD reported here are YSZ/Y[sub 2]O[sub 3]/YBCO and YSZ/CeO[sub 2]/YBCO, respectively, on oxidized Ni RABiTS microalloys (0,1% W) and on SS/YSZ (IBAD) tapes. First, EBSD and AFM techniques have been used to characterize the substrates. Superconducting YBCO films were fully characterized by SEM, XRD and AC susceptibility measurements Epitaxial growth was depicted with a strong in-plane and out-of plane texture: FWHM of YBCO φ-scans were 8.5° on Ni tape and 9° on IBAD Hastelloy tapes. High performances were also measured by AC susceptibility, with J[sub c] values of 0.6 MA/cm² at 77 K (0 T) on Ni tape and close to 1 MA/cm² on IBAD substrates, with a sharp transition (ΔT[sub c] < 0.4 K) and a T[sub c] onset at 90 K. Deposition of 2 meter buffered YSZ and CeO[sub 2]/YBCO films have also been performed showing good in-plane alignment (φ-scan YSZ: FWHM = 11°) with a tape velocity set at 4 m/h. [ABSTRACT FROM AUTHOR]