Study of a Sextupole Round Coil Superferric Magnet

Abstract: The LASA Laboratory (INFN, Milan) is developing a new type of superferric magnets suitable to arbitrary multipole order, which we refer to as round coil superferric magnets. It is based on the previous proposal of I. F. Malyshev and V. Kashikhin. This type of magnet is suitable for strain-sensitive superconductors because it only uses a single round coil, which has a large bending radius, to create the magnetic field. The round yoke with arbitrary multipoles is able to create the desired harmonic component for the magnet. A preliminary electromagnetic design of such magnet in sextupole configuration was presented, using MgB2 superconducting tape for the coil. In this paper, we present the advances in the study for the construction of the prototype. We analyze the electromagnetic properties of the coil and of the round multipole iron yoke, focusing on the optimization of the main desired multipole harmonic. We also study the mechanics and quench protection, considering a new type of MgB2 superconducting cable for the coils. At the end of 2017, the magnet will be assembled in the LASA laboratories and then tested in 2018

Quench Protection Study of the <formula formulatype="inline"><tex Notation="TeX">Nb3Sn\hbox{Nb}_{3}\hbox{Sn} </tex></formula> Low-<formula formulatype="inline"><tex Notation="TeX">β\beta</tex></formula> Quadrupole for the LHC Luminosity Upgrade

In the framework of the HiLumi program, the development of high field (conductor peak field 12 T) and large aperture (150 mm in diameter) superconducting quadrupoles is under way. These quadrupoles will provide the final focusing of the beam in the interaction region of the Large Hadron Collider (LHC), in the program of the luminosity upgrade. The quench protection of these magnets is a challenging aspect, mainly for the magnet dimension (8 m long), for the large value of the stored magnetic energy (12 MJ) and for the use of Nb3Sn as conductor. In this paper, the quench protection study is reported, comparing results obtained with different codes for quench analysis. The parametric analysis of the transition under different conditions for the protection scheme is also presented

Measurements and Analysis of Dynamic Effects in the LARP Model Quadrupole HQ02b During Rapid Discharge

This paper presents the analysis of some quench tests addressed to study the dynamic effects in the 1-m-long 120-mm-aperture Nb$_{3}$Sn quadrupole magnet, i.e., HQ02b, designed, fabricated, and tested by the LHC Accelerator Research Program. The magnet has a short sample gradient of 205 T/m at 1.9 K and a peak field of 14.2 T. The test campaign has been performed at CERN in April 2014. In the specific tests, which were dedicated to the measurements of the dynamic inductance of the magnet during the rapid current discharge for a quench, the protection heaters were activated only in some windings, in order to obtain the measure of the resistive and inductive voltages separately. The analysis of the results confirms a very low value of the dynamic inductance at the beginning of the discharge, which later approaches the nominal value. Indications of dynamic inductance variation were already found from the analysis of current decay during quenches in the previous magnets HQ02a and HQ02a2; however, with this dedicated test of HQ02b, a quantitative measurement and assessment has been possible. An analytical model using interfilament coupling current influence for the inductance lowering has been implemented in the quench calculation code QLASA, and the comparison with experimental data is given. The agreement of the model with the experimental results is very good and allows predicting more accurately the critical parameters in quench analysis (MIITs, hot spot temperature) for the MQXF Nb$_{3}$Sn quadrupoles, which will be installed in the High Luminosity LHC

Intelliquench: An Adaptive Machine Learning System for Detection of Superconducting Magnet Quenches

In superconducting magnets, the irreversible transition of a portion of the conductor to resistive state is called a “quench.” Having large stored energy, magnets can be damaged by quenches due to localized heating, high voltage, or large force transients. Unfortunately, current quench protection systems can only detect a quench after it happens, and mitigating risks in Low Temperature Superconducting (LTS) accelerator magnets often requires fast response (down to ms). Additionally, protection of High Temperature Superconducting (HTS) magnets is still suffering from prohibitively slow quench detection. In this study, we lay the groundwork for a quench prediction system using an auto-encoder fully-connected deep neural network. After dynamically trained with data features extracted from acoustic sensors around the magnet, the system detects anomalous events seconds before the quench in most of our data. While the exact nature of the events is under investigation, we show that the system can “forecast” a quench before it happens under magnet training conditions through a randomized experiment. This opens up the way of integrated data processing, potentially leading to faster and better diagnostics and detection of magnet quenchesIn superconducting magnets, the irreversible transition of a portion of the conductor to resistive state is called a “quench.” Having large stored energy, magnets can be damaged by quenches due to localized heating, high voltage, or large force transients. Unfortunately, current quench protection systems can only detect a quench after it happens, and mitigating risks in Low Temperature Superconducting (LTS) accelerator magnets often requires fast response (down to ms). Additionally, protection of High Temperature Superconducting (HTS) magnets is still suffering from prohibitively slow quench detection. In this study, we lay the groundwork for a quench prediction system using an auto-encoder fully-connected deep neural network. After dynamically trained with data features extracted from acoustic sensors around the magnet, the system detects anomalous events seconds before the quench in most of our data. While the exact nature of the events is under investigation, we show that the system can “forecast” a quench before it happens under magnet training conditions through a randomized experiment. This opens up the way of integrated data processing, potentially leading to faster and better diagnostics and detection of magnet quenches

The EuroCirCol 16T Cosine–Theta Dipole Option for the FCC

EuroCirCol is a conceptual design study for a post-LHC research infrastructure based on an energy-frontier of the 100-TeV circular hadron collider “Future Circular Collider.” In the frame of the high-field accelerator magnet design work package of this study, three different options for dipole magnets providing a field of 16 T in a 50-mm aperture are being considered: block-coils, common-coils, and cosine-theta. All options are being explored and will be compared based on the same assumptions, in particular for what regards the conductor performance, operating temperature, and margin. This paper details the cosine-theta option under development at INFN, showing the electromagnetic and mechanical choices