We demonstrate experimentally a precise realization of Coulomb Blockade Thermometry (CBT) working at temperatures up to 60 K. Advances in nano fabrication methods using electron beam lithography allow us to fabricate a uniform arrays of sufficiently
small tunnel junctions to guarantee an overall temperature reading uncertainty of about 1%
The hold time $tau$ of a single-electron trap is shown to increase significantly due to suppression of environmentally assisted tunneling events. Using two rf-tight radiation shields instead of a single one, we demonstrate increase of $tau$ by a fact
or exceeding $10^3$, up to about 10 hours, for a trap with only two superconductor (S) -- normal-metal (N) tunnel junctions and an on-chip resistor $R$ (R-SNS structure). In the normal state, the improved shielding made it possible to observe $tausim$ 100 s, which is in reasonable agreement with the quantum-leakage-limited level expected for the two-electron cotunneling process.
We present an experimental study of hybrid turnstiles with high charging energies in comparison to the superconducting gap. The device is modeled with the sequential tunneling approximation. The backtunneling effect is shown to limit the amplitude of
the gate drive and thereby the maximum pumped current of the turnstile. We compare results obtained with sine and square wave drive and show how a fast rise time can suppress errors due to leakage current. Quantized current plateaus up to 160 pA are demonstrated.
