Minimal Acquisition Time Polarized Neutron Imaging of Current Induced Magnetic Fields in Superconducting Multifilamentary YBCO Tape

TL;DR

This paper demonstrates the use of polarized neutron imaging to quickly and accurately visualize internal magnetic fields and damage in superconducting YBCO tapes, providing quantitative insights into current-induced magnetic phenomena.

Contribution

It introduces a minimal acquisition time polarized neutron imaging method for analyzing magnetic fields in superconductors, highlighting its ability to detect internal damage and measure screening currents.

Findings

Internal damage regions are easily identified.

Quantitative magnetic field measurements are achieved.

Screening currents are estimated through simulation comparison.

Abstract

In this paper we showcase the strengths of polarized neutron imaging as a magnetic imaging technique through a case study on field-cooled multifilamentary YBCO tape carrying a transport current while containing a trapped magnetic field. The measurements were done at J-PARC's RADEN beamline, measuring a radiograph of a single polarization component, to showcase the analysis potential with minimal acquisition time. Regions of internal damage are easily and accurately identified as the technique probes the internal magnetic field of the sample, thereby avoiding surface-smearing effects. Quantitative measurements of the integrated field strength in various regions are acquired using time-of-flight information. Finally, we estimate the strength of the screening currents in the superconductor during the experiment by simulating an experiment with a model sample and comparing it to the experimental data. With this, we show that polarized neutron imaging is not only a useful tool for investigating magnetic structures but also for investigating samples carrying currents.