Electrical and Thermal View Points for Designing Conduction-Cooled Specimen Holder for Short Sample Testing

Abstract

Abstract Theelectrical and stabilitypropertiesof superconductivestrandsareoftencharacterizedby short sample testing.These tests are often done in a measurement system where the sample is cooled by liquid cryogen or cold gas flow. In both approaches, the sample temperature during a measurement is stabilized by the abundance of available cooling power. This also helps to protect the sample during a thermal runaway i.e. quench. However, in some characterizations, e.g. minimum quench energy testing, the cooling conditions can have a significant effect on the results. Therefore a more adiabatic solution is prefer able as iten able seasier comparison of the results from different measurement stations. One solution to achieving the desired adiabacy is to use conduction-cooling and vacuum insulation. As there is no cooling fluidtorelyon, as cheme for sample protection has to be implemented. Inaconduction-cooled setup, one way to protect the sampleis to use an active protection system in conjunction with aproperly designed sample holder. In this publication, we present an electrical and thermal analysis of a conduction-cooled sample holder suitable for both critical current and minimum quench energy measurements. A coupled electro-thermal finite element method model was constructed to study the sample holder performance during measurement. For our application, the performance is defined by the ohmic losses in the holder component sand by the recovery time from as amplequench.