Fast polarized neutron imaging for estimating screening current in superconducting multifilamentary YBCO tape.

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, and the analysis is based on a radiograph of a single polarization component, to showcase the analysis potential for fast measurements with short acquisition time. Regions of internal damage are easily and accurately identified as the technique probes the internal magnetic field of the sample directly. Quantitative measurements of the integrated field strength in various regions are acquired using time-of-flight information. Finally, the strength of the screening currents in each filament of the superconductor are estimated by simulating an experiment with a model sample and comparing it to data. With this, we show that polarized neutron imaging is not only a useful tool for investigating magnetic structures but also for investigating currents.