Utveckling av styrprogram för mätning av kritisk strömtäthet i supraledare

Sammanfattning: Superconductivity is in the process of going from research into engineering disciplines. It is desirable to determine whether a particular superconducting material is applicable for a specific application by determining its physical limitations. The focus in this paper is directed to limitations in applied current density, and the design of software to be able to measure this parameter. We have developed the software in Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) to extend an existing control program at the Electrum Laboratory (KTH). The developed software's functionality is verified during the work in measurements on precision resistors with very low resistance, in order to verify that correct IV characteristic is achieved. This has shown that the measured data are consistent with the specifications and that the software is working properly. The critical current density has been measured by a pulse method, performed on a superconducting material composed of Y Ba2Cu3O7 at temperatures below 90 K (-183oC). Achieved data from the measurements are analyzed and show that the developed software can be used to estimate critical current densities with fair precision.