EuCARD-2 is a project supported by FP7-European Commission that includes, inter alia, a work-package (WP10) called "Future Magnets." This project is part of the long term development that CERN is ...launching to explore magnet technology at 16 T to 20 T dipole operating field, within the scope of a study on Future Circular Colliders. The EuCARD2 collaboration is closely liaising with similar programs for high field accelerator magnets in the USA and Japan. The main focus of EuCARD2 WP10 is the development of a 10 kA-class superconducting, high current density cable suitable for accelerator magnets, The cable will be used to wind a stand-alone magnet 500 mm long and with an aperture of 40 mm. This magnet should yield 5 T, when stand-alone, and will enable to reach a 15 to 18 T dipole field by placing it in a large bore background dipole of 12-15 T. REBCO based Roebel cables is the baseline. Various magnet configurations with HTS tapes are under investigation and also use of Bi-2212 round wire based cables is considered. The paper presents the structure of the collaboration and describes the main choices made in the first year of the program, which has a breadth of five to six years of which four are covered by the FP7 frame.
Abstract
The High Luminosity Large Hadron Collider (HL-LHC) is the new flagship project of CERN. First endorsed in 2013 and approved in 2016, HL-LHC is an upgrade of the accelerator aiming to ...increase by a factor of ten the statistics of the LHC collisions at the horizon of 2035–2040. HL-LHC relies on cutting edge technologies: among them, large aperture superconducting magnets will replace the present hardware to allow a smaller beam size in two interaction points (IPs). The project involves the construction of about 150 magnets of six different types: the quadrupole triplet, two main dipoles and three orbit correctors. The triplet, manufactured at CERN and in the USA, will consist of 30 magnets based on Nb
3
Sn technology, with an operational peak field of 11.4 T. These will be the first quadrupole Nb
3
Sn magnets installed in a particle accelerator. The other five types of magnets, all relying on Nb–Ti technology, present non-trivial challenges in the design and construction; they will be manufactured as part of in-kind contribution under the responsibility of institutes in Japan, China, Spain, and Italy. The project is now in the phase of transition between qualification through short models and prototypes and the beginning of the series construction. In this paper we review the magnet requirements, the reasons for selecting the design, the technological challenges with respect to previous projects, and we summarize the steps that have been taken to validate the baseline.
EuCARD-2 is a project partly supported by FP7-European Commission aiming at exploring accelerator magnet technology for 20 T dipole operating field. The EuCARD-2 collaboration is liaising with ...similar programs for high field magnets in the USA and Japan. EuCARD-2 focuses, through the work-package 10 "Future magnets," on the development of a 10 kA-class superconducting, high current density cable suitable for accelerator magnets, for a 5 T stand-alone dipole of 40 mm bore and about 1 m length. After standalone testing, the magnet will possibly be inserted in a large bore background dipole, to be tested at a peak field up to 18 T. This paper starts by reporting on a few of the highlight simulations that demonstrate the progress made in predicting: dynamic current distribution and influence on field quality, complex quench propagation between tapes, and minimum quench energy in the multitape cable. The multiphysics output importantly helps predicting quench signals and guides the development of the novel early detection systems. Knowing current position within individual tapes of each cable we present stress distribution throughout the coils. We report on the development of the mechanical component and assembly processes selected for Feather-M2 the 5 T EuCARD2 magnet. We describe the CERN variable temperature flowing helium cold gas test system. We describe the parallel integration of the FPGA early quench detection system, using pickup coils and temperature sensors, alongside the standard CERN magnet quench detection system using voltage taps. Finally we report on the first cold tests of the REBCO 10 kA class Roebel subscale coil named Feather-M0.
The design, fabrication, and tests of the new generation of superconducting magnets for the High Luminosity upgrade of the Large Hadron Collider (HL-LHC) require the support of an adequate sensing ...technology able to assure the integrity of the strain-sensitive and brittle superconducting cables through the whole service life of the magnet: assembly up to 150 MPa, cool down to 1.9 K, and powering up to about 16 kA. A precise temperature monitoring is also needed, in order to guarantee the safe working condition of the superconducting cables in the power transmission lines (SC-Link) designed to feed the magnet over long distance. Fiber Bragg Grating-based temperature and strain monitoring systems have been implemented in the first SC-Link prototype and in two subscale dipole magnets and tested in the cryogenic test facility at CERN, at 30 K, 77 K, and 1.9 K.
This contribution describes the experimental program already undergoing and to be completed on the High Luminosity Large Hadron Collider (HL-LHC) Inner Triplet (IT) String, an important intermediate ...milestone of the HL-LHC project at CERN. First, it describes the magnet circuits of the HL-LHC IT String. Afterwards, the different systems installed to perform the experimental program are detailed. The proposed tests are defined for the validation of the cryogenic system, the full remote alignment system, the powering system, and the protection schemes of all magnets working in unison. This strategy will allow for a verification of the integrated powering system before the final installation and commissioning in the HL-LHC's underground areas.
Racetrack model coils (RMC) have been built at CERN during the past decade, as an R&D tool to qualify conductors and technologies developed for high field superconducting accelerator magnets (Perez ...et al. , 2016). RMC, assembled in a dipole magnet configuration, proved to be an efficient instrument reducing cost and feed-back time while developing new magnets. In a similar way, as for the High-Luminosity Large Hadron Collider (HL-LHC) project, CERN has designed the enhanced RMC (eRMC) made of two flat coils using 40 (1 mm diameter) Nb 3 Sn strand cable produced with Rod Restack Process (RRP) technology. This conductor geometry, originally designed and produced to build the block coil dipole magnet FRESCA2 (Rochepault et al. , 2019), was chosen to reduce the production time and shorten the road towards the feasibility demonstration to reach 16-18 T magnetic fields in a dipolar configuration. Like previous model coils built at CERN (Short model coils (SMC) & RMC), eRMC1a has been built using the "bladders and keys" type mechanical structure. This paper describes the main construction steps and the powering test results. At 1.9 K the magnet produced 16.5 T peak field in the conductor, the highest ever for a dipole magnet of this configuration.
The High-Luminosity project (HL-LHC) of the CERN Large Hadron Collider (LHC), requires low <inline-formula><tex-math notation="LaTeX">\beta</tex-math></inline-formula>* quadrupole magnets in Nb ...<inline-formula><tex-math notation="LaTeX">_\text{3}</tex-math></inline-formula>Sn technology that will be installed on each side of the ATLAS and CMS experiments. After a successful short-model magnet manufacture and test campaign, the project has advanced with the production, assembly, and test of full-size 7.15-m-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 <inline-formula><tex-math notation="LaTeX">_\text{3}</tex-math></inline-formula>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.
The luminosity upgrade of the Large Hadron Collider (HL-LHC) requires the development of a new generation of superconducting magnets based on Nb 3 Sn technology. To monitor the magnet ...thermo-mechanical behavior during its service life, from the coil fabrication to the magnet operation, reliable sensing systems need to be implemented. In the framework of the FP7 European Project EUCARD, Nb 3 Sn racetrack coils are developed as test beds for the fabrication validation, the cable characterization, and the instrumentation development. Fiber optic sensors (FOS) based on fiber Bragg grating (FBG) technology have been embedded in the coils of the short model coil (SMC) magnet. The FBG sensitivity to both temperature and strain required the development of a solution able to separate the mechanical and temperature effects. This paper presents the feasibility study of the implementation of embedded FBG sensors for the temperature and strain monitoring of the 11-T-type conductor. We aim to monitor and register these effects during the coil fabrication and cool down in a standalone configuration.
This paper describes the standalone magnet cold testing of the high temperature superconducting (HTS) magnet Feather-M2.1-2. This magnet was constructed within the European funded FP7-EUCARD2 ...collaboration to test a Roebel type HTS cable, and is one of the first high temperature superconducting dipole magnets in the world. The magnet was operated in forced flow helium gas with temperatures ranging between 5 and 85 K. During the tests a magnetic dipole field of 3.1 T was reached inside the aperture at a current of 6.5 kA and a temperature of 5.7 K. These values are in agreement with the self-field critical current of the used SuperOx cable assembled with Sunam tapes (low-performance batch), thereby confirming that no degradation occurred during winding, impregnation, assembly and cool-down of the magnet. The magnet was quenched many tens of times by ramping over the critical current and no degradation nor training was evident. During the tests the voltage over the coil was monitored in the microvolt range. An inductive cancellation wire was used to remove the inductive component, thereby significantly reducing noise levels. Close to the quench current, drift was detected both in temperature and voltage over the coil. This drifting happens in a time scale of minutes and is a clear indication that the magnet has reached its limit. All quenches happened approximately at the same average electric field and thus none of the quenches occurred unexpectedly.
HL-LHC IT STRING: Status and Perspectives Bajko, M.; Baglin, V.; Ballarino, A. ...
IEEE transactions on applied superconductivity,
08/2024, Letnik:
34, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The HL-LHC IT STRING, an integrated test stand for the major components of the HL-LHC Inner Triplet (IT) zone, is in its construction phase in a surface building at CERN. The main motivation is to ...study and validate the collective behavior of the different systems: magnets, circuit protection, cryogenics for magnets and superconducting link, magnet powering, vacuum, alignment, and interconnections between magnets and superconducting link. During the past two years, the major focus has been on the technical infrastructure definition and implementation, while preparing the installation sequences and procedures for the major elements. The String Validation Program (SVP) has been agreed with the HL-LHC Work Packages, allowing to set up a joint and optimized test program and to integrate it in a schedule. In this paper we describe the IT String installations and describe the main differences between the HL-LHC IT String and the future HL-LHC machine. The main line of the test program and the motivation of a full thermal cycle with a cost benefit analysis will be presented.
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