Rf SQUID (Superconducting Quantum Interference Device) Detector for Single-Ion Trapping Experiments

摘要

The authors have designed and constructed a novel superconducting detector sensitive enough to detect the axial motion of a single, trapped ion. This detector employs a tuned, superconducting transformer matched to a rf SQUID (superconducting quantum interference device) to yield an effective current sensitivity of 2.7 x 10 to the -15 power A/the square root of Hz at 160 kHz. To optimize the detection system, the authors have used existing small-signal equivalent circuit models, and thus have tested these models in a new regime. The authors include details of our superconducting circuitry and of the modifications required to stabilize the commercial SQUID controls at 160 kHz. Finally, they present typical detected signals from trapped ions. Reprints. (aw)