F. Rodriguez-Mateos

CERN | CERN · Technology Department (TE)

This contribution describes the experimental program already undergoing and to be completed on the High Luminosity LHC (HL-LHC) 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...

Impedance measurements of superconducting circuits routinely serve as means to anticipate their dynamic response and validate their electrical integrity. Usual procedures involve performing tests on non-powered systems during commissioning and maintenance periods. However, impedance measurements might have a strong potential in diagnostics of power...

Summary of interventions carried out during the LHC (CERN) long shutdown 2 to prepare for Run3 (Consolidations, HL upgrades...) and Run3 operational scenarios

The Large Hadron Collider (LHC) Long Shutdown 2 (2019–2021), following LHC Run 2, was primarily dedicated to the upgrade of the LHC Injectors but it included also a significant amount of activities aimed at consolidation of the LHC machine components, removal of known limitations and initial upgrades in view of the High-Luminosity LHC (HL-LHC) to fa...

This study evaluates the lifetime and aging process of the aluminium electrolytic capacitors to be used in the new protection systems of the High Luminosity LHC superconducting magnets. The accelerated testing and analysis of several groups of capacitors aged for more than one year provided insights into their expected lifespan and aging process. T...

The paper presents a new family of low voltage DC switching energy extraction (EES) systems designed for protection of superconducting magnet circuits at CERN, which is appropriate also in other applications. During normal operation, superconducting magnet circuits can store large amounts of energy in their magnetic fields. In the case of a resisti...

The electrical quality assurance (ELQA) of the superconducting circuits of CERN's Large Hadron Collider (LHC) during its second Long Shutdown (LS2) requires the execution of vast measurement campaigns. Each of 1658 electrical circuits as well as the instrumentation of each of the 1746 individual cryo-assemblies housing magnets, bus-bars and other c...

Achieving the targets of the High Luminosity LHC project requires the installation of new inner triplet magnet circuits for the final focusing of the particle beams on each side of the two main interaction points. Each of the four circuits will include six 150 mm aperture, 132.2 T/m gradient, Nb3Sn quadrupole magnets to be installed in the LHC tunn...

An energy of 362 MJ is stored in each of the two LHC proton beams for nominal beam parameters. This will be further increased to about 700 MJ in the future high luminosity LHC (HL-LHC) and uncontrolled beam losses represent a significant hazard for the integrity and safe operation of the machine. In this paper, a number of failure mechanisms that c...

Cryogenic bypass diodes are part of the baseline powering layout for the circuits of the new Nb3Sn based final focus magnets of the high luminosity Large Hadron Collider. They will protect the magnets against excessive transient voltages during a nonuniform quenching process. The diodes are located inside an extension to the magnet cryostat, operat...

An energy of $362\:\text{MJ}$ is stored in each of the two LHC proton beams for nominal beam parameters. This will be further increased to about $700\:\text{MJ}$ in the future High Luminosity LHC (HL-LHC) and uncontrolled beam losses represent a significant hazard for the integrity and safe operation of the machine. In this paper, a number of failu...

Cryogenic bypass diodes have been installed in all superconducting dipole magnets (1232) and quadrupole magnets (392) of the Large Hadron Collider (LHC) at CERN, and operated during the physics runs since 2009. The bypass diodes are a fundamental ingredient of the quench protection system for those main dipoles and quadrupoles magnets. The diodes a...

The quadrupole magnets for the Large Hadron Collider (LHC) upgrade to higher luminosity are jointly developed by CERN and US-LARP (LHC Accelerator Research Program). These Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn magnets will be protected against overheating after a quench by a com...

The European Organization for Nuclear Research (CERN) and U.S. LHC Accelerator Research Program (LARP) are jointly developing Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn quadrupole magnets to be installed in the LHC for its upgrade to higher luminosity. These magnets' quench protectio...

The newly developed concept of Coupling-Loss Induced Quench (CLIQ) used in the domain of superconducting magnets quench protection has opened a new path towards efficient magnet protection. Subsequently to the first trials using ad hoc solutions in order to confirm functionality and performance of the method, two pre-series of three units each with...

The superconducting dipole magnets of the Large Hadron Collider operate in a superfluid helium bath at 1.9K. As a part of the magnet quench protection system, each dipole magnet is equipped with a bypass diode located in the helium bath. The connection between the superconducting magnet and the cold by-pass diode is made through a clamping system c...

The operation of the High-Luminosity LHC (HL-LHC) relies on the development and operation of new high-field, Nb3Sn based magnets in the two high luminosity regions of the LHC. Several short model and long prototype magnets as well as the final production batch will be extensively tested and validated in dedicated magnet test facilities at CERN. For...

The upgrade of the LHC to achieve higher luminosity requires the installation of twenty-four 150 mm aperture, 12 T, Nb3Sn quadrupole magnets close to the two interaction regions at ATLAS and CMS. The protection of these high field magnets after a quench is particularly challenging due to the high stored energy density, which calls for a fast, effec...

The goal of the High Luminosity LHC project is upgrading the LHC in order to increase its luminosity by a factor of five. To achieve this, 24 150-mm-aperture 12-T Nb 3Sn quadrupole magnets are to be installed close to the two interaction regions at ATLAS and CMS. This new generation of high-field magnets poses a significant challenge concerning the...

Quench heaters are an essential part of the protection of all high-current large hadron collider (LHC) superconducting circuits. About 2000 dipole and quadrupole magnets are equipped with quench heaters in order to protect them against development of excessive voltage and overheating after a resistive transition. The quench heaters are made of stai...

Due to their pulsed and fast discharge operation, the superconducting systems of ITER will experience high voltage variations and, as a result, the instrumentation for quench detection will also experience those high voltage levels. Therefore the risk of an electrical breakdown between instrumentation wires and ground cannot be discarded. Current L...

The design of the ITER primary quench detection system is nearly completion, and the baseline is presented in this article. The paper describes the primary quench detection devices that will protect the magnets against the quench in the cable-in-conduits conductors of the coils. The CS will be protected by one system based on co-wound tapes, and an...

This paper outlines the key points in the specification of insulating breaks that must be inserted in the cryogenic cooling lines that supply super critical helium, at 4.5 K to the magnet system of ITER. Electrical requirements, including partial discharge and breakdown under Paschen conditions are described as well as the pressure leak tightness a...

In the ITER superconducting magnets the dielectric separation between the CICC (Cable-In-Conduit Conductors) and the helium supply pipes is made through the so-called insulating breaks (IB). These devices shall provide the required dielectric insulation at a 30 kV level under different types of stresses and constraints: thermal, mechanical, dielect...

The primary quench detection for ITER magnets is classically based on resistive voltage measurements. In addition, a safety related secondary quench detection relying on signals of thermohydraulic nature is required for the TF coils. Although not required by safety, a similar secondary quench detection system has been investigated for the other ITE...

The ITER tokamak is a very complex electromagnetic system that requires a careful assessment for for assuring its reliable operation as well as its mechanical integrity. In this paper we discuss the effects of the fast electromagnetic transients on the superconducting magnet system. Of particular complexity is the analysis of the quench detection s...

The Central Solenoid (CS) of the ITER Magnet system is split into six independently powered coils enclosed inside an external structure which provides vertical precompression thus preventing separation of the coils and acting as a support to net resulting loads. The analyses include an assessment of the mechanical behavior of the different componen...

During a fast discharge of the TF system, eddy currents and high associated heat production in the winding plates can induce a quench by heat transfer. A quasi 2D model based on the coupled GANDALF and FLOWER codes allows the calculation of the radial heat transfer from the plates to the CICC through the conductor insulation as well as hydraulic tr...

In order to ensure the safety of the ITER TF magnets, a primary quench detection system has been foreseen, based on voltage detection. In addition, a secondary quench detection could rely on signals of thermo-hydraulic nature. As a matter of fact, the development of a quench in a CICC leads to significant variations of pressure and mass flow at the...

At variance with most of the existing superconducting systems operating in the world, the ITER central solenoid (CS) magnet is a fast pulsed system. This peculiarity creates a specific situation regarding the quench detection system, as a small resistive signal associated with a quench has to be discriminated from the high inductive signals imposed...

The quench detection system in ITER superconducting magnet systems is a real challenge for the poloidal field (PF) system and the central solenoid (CS) due to their fast-pulsed operation. An existing CEA code allowing very precise magnetic field calculations in tokamaks (Traps) has been upgraded (TrapsAv) to calculate the inductive voltages induced...

The commissioning of the Large Hadron Collider at CERN includes the powering of about 1600 superconducting electrical circuits to currents ranging from 55Â A to 11.8 kA. A large number of splices (over 70'000) are present at the magnet interconnects, which can only be validated with current at cryogenic conditions. This paper discusses the thermal...

The protection system for the superconducting elements of the Large Hadron Collider (LHC) at the European Laboratory for Particle Physics (CERN), and its associated equipment are presented: quench detectors, cold diodes, quench heaters and related power supplies, extraction resistors and associated current breakers. Features such as radiation resis...

High field superconducting magnets working at superfluid helium temperature are requested for the 7 TeV LHC accelerator. Several single and twin aperture 1 m long dipole models were measured to compare the differences in behaviour due to design and fabrication. They are shown to be valid models to predict the behaviour of full length magnets. The a...

Following the successful testing of the first 1-metre model of the 70 mm aperture quadrupole for the LHC low- insertions, two further 1-metre magnets have been built. All magnets feature a four-layer coil wound from two 8.2 mm wide graded NbTi cables and a four-way split yoke supporting structure. In this paper we review the training history of the...