Circuit model for HTS flux pump with flux conservation, dynamic resistance, and flux flow

A switchless HTS flux pump and circuit model for a centimeter scale double-loop superconducting circuit of 2Gtape are presented. The flux pump mechanism − which does not use a traveling magnetic wave − operates via the generation of finite resistivity in the different arms of the multiply-connected superconducting circuit, resulting in the build up of a nonzero dc voltage which drives a superconducting persistent current. Using the principle of flux conservation, flux flow, and dynamic resistance, a theoretical model is given which is in qualitative agreement with the preliminary data presented.</p

Circuit model for HTS flux pump with flux conservation, dynamic resistance, and flux flow

A switchless HTS flux pump and circuit model for a centimeter scale double-loop superconducting circuit of 2Gtape are presented. The flux pump mechanism − which does not use a traveling magnetic wave − operates via the generation of finite resistivity in the different arms of the multiply-connected superconducting circuit, resulting in the build up of a nonzero dc voltage which drives a superconducting persistent current. Using the principle of flux conservation, flux flow, and dynamic resistance, a theoretical model is given which is in qualitative agreement with the preliminary data presented.</p

High frequency properties of a planar ion trap fabricated on a chip

We report on the measurement of the high frequency properties of a planar Penning ion trap fabricated on a chip. Two types of chips have been measured: the first manufactured by photolithographic metal deposition on a p-doped silicon substrate and the second made with printed circuit board technology on an alumina substrate. The input capacitances and the admittances between the different trap's electrodes play a critical role in the electronic detection of the trapped particles. The measured input capacitances of the photolithographic chip amount to 65-76 pF, while the values for the printed circuit board chips are in the range of 3-5 pF. The latter are small enough for detecting non-destructively a single trapped electron or ion with a specifically tuned LC resonator. We have also measured a mutual capacitance of ∼85 fF between two of the trap's electrodes in the printed circuit board chip. This enables the detection of single, or very few, trapped particles in a broader range of charge-to-mass ratios with a simple resistor on the chip. We provide analytic calculations of the capacitances and discuss their origin and possible further reduction.</p