Accurate Coulomb Blockade Thermometry up to 60

Primary thermometers are required for the ongoing effort to redefine the Kelvin scale based directly on a fundamental physical constant, namely a fixed value of the Boltzmann constant kB [1]. This task requires primary thermometer realizations using different approaches, where consistency between different methods is compulsory. Noise thermometers, like the Magnetic Field Fluctuation Thermometer (MFFT)[2, 3], Current Sensing Noise Thermometry (CSNT) [4] and the CBT [5] are actually candidates that are under consideration for the low temperature range. Experimentally, the method of CBT is a well established tool for precise determination of temperatures below 1 K [5, 6] with good precision [7]. At higher temperatures though, fabrication inhomogeneities [8] are setting strict limits to the feasibility of CBT, so that no precise sensors operating above about 10 K were reported so far. We will present in this work a CBT operating at temperatures up to 60 K and discuss the uncertainty component arising from fabrication imperfections.