Numerical simulation and experimental validation of the re-design of high Tc current leads for the astro-E2 X-Ray spectrometer detector system

Abstract

The herein presented research work consists on the redesign and thermal model development of the X-Ray Spectrometer (XRS) High Tc Superconducting Current (HTSC) lead assembly. The HTSC leads are used to provide current to the Adiabatic Demagnetization Refrigerator (ADR), which is used for cooling the XRS instrument to a 60 mK platform. The XRS is intended to study X-Rays emitted by astronomical objects, such as black holes, to determine their X-Ray spectrum. In order to achieve a 2.5-year lifetime goal for the XRS it is necessary to developed low thermal conductance leads to supply current to the ADR magnet and the cryostat valve motors with a minimal heat load. Superconducting Magnesium Diboride (MgB2) wires, with 39 K superconductivity, are used to conduct current from the 17 K support structure to the 4 K vapor cooled stage. Nobidium Titanium (NbTi) wires are used to provide a superconducting path from the 4 K stage to the magnet and valves on the 1.3 K Helium cryostat. This research investigation aimed to develop a prototype of the HTSC lead assembly and a computer model to simulate the thermal behavior of this system. Experimental data from the prototype was used to validate the thermal model, which was employed to minimize heat loads in the design