Instrumentation status of the low-b magnet systems at the Large Hadron Collider (LHC) (original) (raw)
Related papers
2010
The insertion regions located around the four interaction points of the Large Hadron Collider (LHC) are mainly composed of the low-β triplets, the separation dipoles and their respective electrical feed-boxes (DFBX). The low-β triplets are Nb-Ti superconductor quadrupole magnets, which operate at 215 T/m in superfluid helium at a temperature of 1.9 K. The commissioning and the first operation of these components have been performed. The thermo-mechanical behavior of the low-β triplets and DFBX were studied. Cooling and control systems were tuned to optimize the cryogenic operation of the insertion regions. Hardware commissioning also permitted to test the system response. This paper summarizes the performance results and the lessons learned.
Performance of the Main Dipole Magnet Circuits of the LHC during Commissioning
2008
During hardware commissioning of the Large Hadron Collider (LHC), 8 main dipole circuits will be tested at 1.9 K and up to their nominal current. Each dipole circuit contains 154 magnets of 15 m length, and has a total stored energy of up to 1.3 GJ. All magnets are wound from Nb-Ti superconducting Rutherford cables, and contain heaters to quickly
Test Results of the First Pre-Series Quadrupole Magnets for the LHC Hi-Lumi Upgrade
IEEE Transactions on Applied Superconductivity, 2021
The future high luminosity (Hi-Lumi) upgrade of the Large Hadron Collider (LHC) at CERN will include eight (plus two spares) 10.2 m-long Cryo-assemblies which will be components of the triplets for two LHC insertion regions. Each cold mass in the Cryo-assemblies will consist of two 4.2 m-long Nb3Sn high gradient quadrupole magnets, designated MQXFA, with aperture 150 mm and operating gradient 132.2 T/m, for a total of twenty magnets. Before assembling and testing the final cold masses at Fermilab, the component quadrupoles are being tested first at the vertical superconducting magnet test facility of the Superconducting Magnet Division (SMD) at Brookhaven National Laboratory (BNL), in superfluid He at 1.9 K and up to 18.0 kA, in accordance with operational requirements of the LHC. The tests of the first two full-length prototype quadrupole magnets MQXFAP1 and MQXFAP2 at BNL have been reported previously. The first two pre-series magnets, the first two that will be used in the LHC, have also now been tested. This paper reports on the quench test and training results of these two magnets. The test results of these magnets will be important for validating the final MQXFA design for operational magnets.
Power Test of the First Two HL-LHC Insertion Quadrupole Magnets Built at CERN
IEEE Transactions on Applied Superconductivity, 2022
The High-Luminosity project (HL-LHC) of the CERN Large Hadron Collider (LHC), requires low β* quadrupole magnets in Nb 3 Sn technology that will be installed on each side of the ATLAS and CMS experiments. After a successful shortmodel magnet manufacture and test campaign, the project has advanced with the production, assembly, and test of full-size 7.15m-long magnets. In the last two years, two CERN-built prototypes (MQXFBP1 and MQXFBP2) have been tested and magnetically measured at the CERN SM18 test facility. These are the longest accelerator magnets based on Nb 3 Sn technology built and tested to date. In this paper, we present the test and analysis results of these two magnets, with emphasis on quenches and training, voltage-current measurements and the quench localization with voltage taps and a new quench antenna. Index Terms-Low beta quadrupole, Nb 3 Sn, quench, superconducting magnets. I. INTRODUCTION A S PART of the HL-LHC project at CERN, the Nb-Ti inner triplet quadrupole magnets near the ATLAS and CMS interaction points will be replaced with large aperture Nb 3 Sn quadrupole magnets, named MQXF [1], [2]. These magnets are developed, manufactured, and tested in a collaboration between CERN and the US HL-LHC Accelerator Upgrade Project (AUP). The MQXF program includes the construction and test of several short-length model magnets, the 4.2-m-long magnets for Q1 and Q3 (constructed by AUP [3]), and the 7.15-m-long magnets for Q2a and Q2b (MQXFB, constructed by CERN). The first two MQXFB full-length prototype magnets (MQXFBP1 and MQXFBP2) were manufactured, assembled and cryostated at CERN [4]. MQXFBP1 was tested in summer-fall 2020, and MQXFBP2 was tested in winter-spring and fall 2021.
A system for series magnetic measurements of the LHC main quadrupoles
IEEE Transactions on Appiled Superconductivity, 2002
More than 400 twin aperture lattice quadrupoles are needed for the Large Hadron Collider (LHC) which is under construction at CERN. The main quadrupole is assembled with correction magnets in a common cryostat called the Short Straight Section (SSS). We plan to measure all SSSs in cold conditions with an unprecedented accuracy: integrated gradient of the field within 150 ppm, harmonics in a range of 1 to 5 ppm, magnetic axis of all elements within 0.1 mm and their field direction within 0.2 mrad. In this paper we describe the automatic measurement system that we have designed, built, and calibrated. Based on the results obtained on the two first prototypes of the SSSs (SSS3 and SSS4) we show that this system meets all above requirements.
Electrical and Magnetic Performance of the LHC Short Straight Sections
IEEE Transactions on Applied Superconductivity, 2006
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 do-decapole 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.
The test facility for the short prototypes of the LHC superconducting magnets
AIP Conference Proceedings, 2002
The LHC development program relies on cryogenic tests of prototype and model magnets. This vigorous program is pursued in a dedicated test facility based on several vertical cryostats working at superfluid helium temperatures. The performance of the facility is detailed. Goals and test equipment for currently performed studies are reviewed: quench analysis and magnet protection studies, measurement of the field quality, test of ancillary electrical equipment like diodes and busbars. The paper covers the equipment available for tests of prototypes and some special series of LHC magnets to come.
Experimental qualification of the platform for magnetic measurements at CERN
The experimental qualification of a new platform for magnetic measurements at the European Organization for Nuclear Research (CERN) is presented. The platform was validated in comparison with the CERN standard test magnet system at warm conditions using the rotating coil method on a superconducting dipole of the Large Hadron Collider. Further characterization tests were carried out at cryogenic temperature (1.9 K) in order to analyze dynamic phenomena of superconducting magnets with a time resolution never reached before.
Measurements of the LHC Corrector Magnets at Room and Cryogenic Temperatures
The superconducting twin aperture main dipole magnets of the LHC accelerator are equipped with pairs of sextupole and decapole correctors at their ends. Similarly, octupole correctors are aligned at t he end of the main quadrupole magnets. Dedicated stations have been built for tests of these correctors at room temperature as well as superfluid helium temperature. Measurements of the training behav iour and of the magnetic field quality are routinely performed. The search for the magnetic axis and the transfer of its position to fiducials are performed at room temperature. A description and the performances obtained with these two benches are also presented.
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 highluminosity 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.