Highly sensitive superconducting circuits at ∼700 kHz with tunable quality factors for image-current detection of single trapped antiprotons

We developed highly sensitiveimage-currentdetectionsystems based on superconductingtoroidal coils and ultra-lownoiseamplifiers for non-destructivemeasurements of the axial frequencies (550 –800 kHz) of single antiprotons stored in acryogenic multi-Penning-trapsystem. 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-lownoiseamplifiers and the trapsystem, 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 thedetector ’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 improvedmeasurements of the proton-to-antiproton charge-to-mass ratio.

Source: Review of Scientific Instruments - November 15, 2016 Category: Physics Authors: H. Nagahama, G. Schneider, A. Mooser, C. Smorra, S. Sellner, J. Harrington, T. Higuchi, M. Borchert, T. Tanaka, M. Besirli, K. Blaum, Y. Matsuda, C. Ospelkaus, W. Quint, J. Walz, Y. Yamazaki and S. Ulmer Source Type: research