Parallel Nuclear Refrigerators for Cooling Nanoscale Samples to Microkelvin Temperatures Master’s Thesis

Based on experiments with a prototype version, we describe the design and the construction of an improved second generation nuclear refrigera-tion stage to cool electrons in a nanoscale sample to microkelvin temper-atures: 21 copper plates are used in parallel for cooling separately every lead connected to the sample by using the well established technique of adiabatic nuclear refrigeration. Main improvements are carefully chosen materials and a rigid support structure that prevents vibrations aiming to achieve a smaller heat leak. In addition, estimates on the performance of the new stage are given looking at precooling times, thermal conductances and eddy current heating