Our article "Highly sensitive superconducting circuits at ∼700 kHz with tunable quality factors for image-current detection of single trapped antiprotons" has been published in Review of Scientific Instruments. There we describe 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 the BASE multi-Penning-trap system.

A crucuial device in the BASE multi-Penning trap system is a reservoir trap for antiprotons. This trap is loaded with a cloud of antiprotons provided by CERN's antiproton decelerator and methods were developed to extract single particles from this reservoir and to supply them to our high precision measurement traps. This allows BASE to continuously perform experiments with antiprotons, independent from accelerator maintenance and shutdown cycles.

A short overview-article on BASE has been released in CERN's EP-newsletter.

We developed a technique to extract arbitrary fractions of antiprotons in a reservoir trap. This method enables us to operate BASE almost independent from accelerator cycles, and especially during the winter shut-down when magnetic field noise in the antiproton decelerator hall is low. For further details read this article.  

In a paper published today in Nature we report the high-precision comparison of the antiproton-to-proton charge to mass ratio. In our measurements we compared the cyclotron frequencies of antiprotons to that of negatively charged hydrogen ions, which are used as a proxy for the proton. We achieved a fractional precision of 69 parts in a trillion, which corresponds in our magnetic field of 1.95 Tesla to an absolute energy resolution of 2mHz. Our result is consistent with CPT invariance.

BASE member Stefan Ulmer has been selected to receive the IUPAP Young Scientist Prize 2014 in Fundamental Metrology. With this prize the International Union of Pure and Applied Physics (IUPAP) honors his work on proton and antiproton magnetic moment measurements.

In a paper just published in Nature we report on the first direct high precision measurement of the proton magnetic moment. By application of the elegant double Penning trap technique we achieved a fractional precision of 3.3 parts per billion. Our value is consistent with the currently accepted CODATA value, but 2.5 times more precise.

Congratulations, BASE member Dr. Christian Smorra applied successfully for one of the highly competitive CERN fellowships. We are thankful for the very strong support by CERN.

In a just in Physics Letters B published article we report on the first successful demonstration of the double Penning trap technique with a single proton. This is a major step towards a  measurement of the particle's magnetic moment with ppb precision. The method can be applied to the antiproton, which will enable one of the most sensitive tests of CPT symmetry with baryons.