Compact RF resonator for cryogenic ion traps
  We report on the investigation and implementation of a lumped-component, radio-frequency resonator used in a cryogenic vacuum environment to drive an ion trap. The resonator was required to achieve the voltages necessary to trap (about 100 V), while dissipating as little power as possible (< 250 mW). Ultimately a voltage gain of 100 was measured at 5.7 K. Single calcium ions were confined in a trap driven by this device, providing proof of successful resonator operation at low temperature. 
D. Gandolfi, M. Niedermayr, M. Kumph, M. Brownnutt, R. Blatt
physics.atom-ph quant-ph