title: Highly sensitive superconducting circuits at ∼700 kHz with tunable quality factors for image-current detection of single trapped antiprotons.
abstract: We developed highly sensitive image-current detection systems based on superconducting toroidal coils and ultra-low noise amplifiers for non-destructive measurements of the axial frequencies (550-800 kHz) of single antiprotons stored in a cryogenic multi-Penning-trap system. The unloaded superconducting tuned circuits show quality factors of up to 500 000, which corresponds to a factor of 10 improvement compared to our previously used solenoidal designs. Connected to ultra-low noise amplifiers and the trap system, signal-to-noise-ratios of 30 dB at quality factors of >20 000 are achieved. In addition, we have developed a superconducting switch which allows continuous tuning of the detector's quality factor and to sensitively tune the particle-detector interaction. This allowed us to improve frequency resolution at constant averaging time, which is crucial for single antiproton spin-transition spectroscopy experiments, as well as improved measurements of the proton-to-antiproton charge-to-mass ratio.
authors.affiliation: RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nagahama
authors.affiliation: RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: G
authors.initials: G
authors.lastname: Schneider
authors.affiliation: RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Mooser
authors.affiliation: RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Smorra
authors.affiliation: RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Sellner
authors.affiliation: Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Harrington
authors.affiliation: RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Higuchi
authors.affiliation: Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Borchert
authors.affiliation: RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Besirli
authors.affiliation: Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Blaum
authors.affiliation: Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuda
authors.affiliation: Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Ospelkaus
authors.affiliation: GSI - Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Quint
authors.affiliation: Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Walz
authors.affiliation: RIKEN, Atomic Physics Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamazaki
authors.affiliation: RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ulmer