The LHC Dipole Geometry as Built in Industry

The LHC dipoles magnets are produced in 5 industrial production sites in Europe. The production is well underway and more than half of the total quantity has been delivered to CERN. One of the important characteristics of the dipole magnets is their geometry. To achieve the requested mechanical tolerances on the magnets, which are 15 m long and have a 28 t mass, the final assembly operations includes precise optical measurements. To ensure the good quality and high production rate, the final assembly procedure has been automated as much as possible. The authors report here about the assembly procedure, the features of the software that guides the optical measurements (and consequently the assembly operations) and the results obtained on the geometry in the different sites

Models and experimental results from the wide aperture Nb-Ti magnets for the LHC upgrade

MQXC is a Nb-Ti quadrupole designed to meet the accelerator quality requirements needed for the phase-1 LHC upgrade, now superseded by the high luminosity upgrade foreseen in 2021. The 2-m-long model magnet was tested at room temperature and 1.9 K. The technology developed for this magnet is relevant for other magnets currently under development for the high-luminosity upgrade, namely D1 (at KEK) and the large aperture twin quadrupole Q4 (at CEA). In this paper we present MQXC test results, some of the specialized heat extraction features, spot heaters, temperature sensor mounting and voltage tap development for the special open cable insulation. We look at some problem solving with noisy signals, give an overview of electrical testing, look at how we calculate the coil resistance during at quench and show that the heaters are not working We describe the quench signals and its timing, the development of the quench heaters and give an explanation of an Excel quench calculation and its comparison including the good agreement with the MQXC test results. We propose an improvement to the magnet circuit design to reduce voltage to ground values by factor 2. The program is then used to predict quench Hot-Spot and Voltages values for the D1 dipole and the Q4 quadrupole.Comment: 8 pages, Contribution to WAMSDO 2013: Workshop on Accelerator Magnet, Superconductor, Design and Optimization; 15 - 16 Jan 2013, CERN, Geneva, Switzerlan

Performance of the Superconducting Corrector Magnet Circuits during the Commissioning of the LHC

The LHC is a complex machine requiring more than 7400 superconducting corrector magnets distributed along a circumference of 26.7 km. These magnets are powered in 1446 different electrical circuits at currents ranging from 60 A up to 600 A. Among the corrector circuits the 600 A corrector magnets form the most diverse and differentiated group. All together, about 60000 high current connections had to be made. A fault in a circuit or one of the superconducting connections would have severe consequences for the accelerator operation. All magnets are wound from various types of Nb-Ti superconducting strands, and many contain parallel protection resistors to by-pass the current still flowing in the other magnets of the same circuit when they quench. In this paper the performance of these magnet circuits is presented, focussing on the quench behaviour of the magnets. Quench detection and the performance of the electrical interconnects will be dealt with. The results as measured on the entire circuits are compared to the test results obtained at the reception of the individual magnets

FIRST RESULTS OF AN EXPERIMENT ON ADVANCED COLLIMATOR MATERIALS AT CERN HIRADMAT FACILITY

A comprehensive, first-of-its-kind experiment (HRMT-14) has been recently carried out at CERN HiRadMat facility on six different materials of interest for Beam Intercepting Devices (collimators, targets, dumps). Both traditional materials (Mo, W and Cu alloys) as well as advanced metal/diamond and metal/graphite composites were tested under extreme conditions as to pressure, density and temperature, leading to the development of highly dynamic phenomena as shock-waves, spallation, explosions. Experimental data were acquired, mostly in real time, relying on extensive integrated instrumentation (strain gauges, temperature and vacuum sensors) and on remote acquisition devices (laser Doppler vibrometer and high-speed camera). The experiment was a success under all points of view in spite of the technological challenges and harsh environment. First measurements are in good agreement with results of complex simulations, confirming the effectiveness of the acquisition system and the reliability of advanced numerical methods when material constitutive models are completely available. Valuable information has been collected as to thermalshock robustness of tested materials

Hydrostatic Levelling System Going Mobile

The LHC Collimator Survey Train has alreadyshown that automated survey measurements in theLHC are technically feasible [1]. Nevertheless manyconstraints apply when making automated measure-ments in an accelerator environment. The researchof adapted measurements techniques and strategiesis an essential part in the development process ofa new generation survey train. From the automa-tion point of view, the measurements in the verticalplane are particularly challenging and one solutionwould be the use of a Hydrostatic Levelling System.They are frequently used in high precision monitoringapplications but with a few compromises a mobileand very flexible version can be build. This paperdescribes the approach, development and tests of amobile HLS which is able to cope with the constraintsand boundary conditions given by the LHC

Remote Control of Heterogeneous Sensors for 3D LHC Collimator Alignment

Periodically the alignment of LHC collimators needs to be verified. Access for personnel is limited due to the level of radiation close to the collimators

High-Speed Data Acquisition of Sensor Signals for Physical Model Verification at CERN HiRadMat (SHC-DAQ)

A high-speed data acquisition system was successfully developed and put into production with the sensors in a harsh radiation environment in a couple of months to test new materials impacted by proton beams for future use in beam intercepting devices

New Cryogenic Test Station at CERN for Superconducting Magnets and their Components

Following the optimization planning of the superconducting magnet test facilities at CERN, a new station for vertical test of R&D magnet has been installed in a building already dedicated to horizontal test of long superconducting magnets built for the LHC. This paper describes the main cryogenic and powering characteristics of the new test station. It gives the details of each cryostat and the related equipment that composes the test station. Although the test station is optimized for low temperature superconducting magnet testing, it offers a wide range of possibility for testing equipment and components of magnets and accelerators over a large range of temperature between 1.8 K and 50 K. The test station will be completed in the next coming years with a cryostat, briefly described here, dedicated for large magnets up to 1 m diameter and 2.5 m long