Reassembly and Test of High-Field Nb3Sn Dipole Demonstrator MDPCT1

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 quenches.

Section: A Magnet Datamentioning

confidence: 99%

“…. Anomaly events detected in all of MDPCT1b current ramps[16] using threshold 3.0 and final threshold 1.6 fitted on 6 randomly selected quenches. Anomalous events are detected in the majority (77%) of quenches.…”

mentioning

confidence: 99%

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

Hoang

Boffo

Tran

et al. 2021

“…The reassembled magnet was called MDPCT1b. The maximum field at the magnet center reached 14.5 T at 1.9 K and next to the magnet lead-end it reached 14.6 T [5]. This is 97% of the magnet design field but its performance quickly degraded, especially after a thermal cycle (TC).…”

Section: Introductionmentioning

confidence: 99%

“…A similar strength dipole magnet was developed and tested in Europe [3]. MDPCT1 was initially tested to 14.1 T at 1.9 K and 4.5 K [4] after which its axial support for outer layers (outer coils) was modified and the magnet retested [5]. The reassembled magnet was called MDPCT1b.…”

Section: Introductionmentioning

confidence: 99%

MDPCT1 Quench Data and Performance Analysis

Stoynev

Baldini

Barzi

et al. 2022

MDPCT1 is a four-layer cos-theta Nb3Sn dipole demonstrator developed and tested at FNAL in the framework of the U.S. Magnet Development Program. The magnet reached record fields for accelerator magnets of 14.1 T at 4.5 K in the first test and 14.5 T at 1.9 K in the second test and then showed large degradation. While its inner coils performed exceptionally well with only two quenches up to 14.5 T and no evidence of degradation, the outer coils degraded over the course of testing. By adopting new measurement and analysis techniques at FNAL we are discussing in detail what happened. Both success and failure in our diagnostics are discussed. The evolution of techniques over the course of two tests (and three thermal cycles) shows the path to address challenges brought by the first four-layer magnet tested at FNAL. This paper presents the analysis of quench data along with diagnostic features and complementary measurements taken in support of the magnet performance analysis.

“…Details of magnet design, fabrication and performance in the first build have been reported previously [1]. The details of MDPCT1b re-assembly and quench performance test are reported in paper [4] at this conference. Here we present the results of the MDPCT1b magnetic measurements, including dipole strength, geometrical field harmonics, and magnetization and yoke saturation effects, emphasizing field changes with respect to the original build [5].…”

Section: Introductionmentioning

confidence: 99%

Field Measurement Results of the 15 T Nb₃Sn Dipole Demonstrator MDPCT1b

DiMarco

Baldini

Barzi

et al. 2021

Self Cite

A 15 T Nb3Sn dipole, MDPCT1, with cos-theta-type coils was developed to demonstrate a possible magnet design for a post-LHC proton-proton Collider. The magnet has 4-layer coils with 60-mm aperture, and has graded current density between the inner and outer layers to maximize performance. The coils are constrained by vertically-split, thick iron laminations, connected by aluminum I-clamps, and a thick stainless-steel skin. The magnet was previously tested at Fermilab with reduced pre-load, and achieved record 14.1 T fields at 4.5 K. Now the magnet was reassembled with full pre-load and cryogenically retested. This paper reports the magnetic measurements results of these tests, including field strength, geometrical harmonics, coil magnetization, and iron saturation characteristics of the demonstrator.