Post-doc position: BASE-CERN

Currently one open post-doc position is available on the BASE CERN experiment.

The BASE collaboration at the antiproton decelerator facility of CERN is performing high-precision comparisons of the fundamental properties of protons and antiprotons. Using advanced, ultra-stable, cryogenic particle traps and superconducting detectors with single particle sensitivity, we have performed the most precise measurement of the proton-to-antiproton charge-to-mass ratio with a fractional precision of 11 significant digits. In another measurement, we have invented a novel spectroscopy method, which allowed for the first ultra-high precision measurement of the antiproton magnetic moment with a fractional precision of 1.5 parts in a billion. Together with our recent measurement of the proton magnetic moment this improves the precision of previous experiments by more than a factor of 3000. A time series analysis of this recent magnetic moment measurement furthermore enabled us to set first direct constraints on the interaction of antiprotons with axion like particles.

A post doc will be involved in all aspects of the operation of BASE. Therefore, we are looking for a candidate with experience in precision measurements, cryogenic engineering, electronics, software engineering, data analysis, and all aspects which are required for the successful operation of an advanced experimental Penning-trap physics laboratory.

The candidate will either be employed by the Max Planck Institute for Nulear Physics, Heidelberg, Germany (P.I. Klaus Blaum) or by RIKEN Fundamental Symmetries Laboratory, Japan (P.I. Stefan Ulmer). Please send your full CV, information on your scientific tracking record and not less than two recommendation letters to Stefan Ulmer (


PhD position: Transportable antiproton trap BASE-STEP


A PhD position is available in the ERC-project STEP, which is supervised by Christian Smorra at the Institute of Physics at the University of Mainz. The project aims to develop a transportable antiproton trap to improve the high-precision measurements of the BASE collaboration comparing the fundamental properties of protons and antiprotons in advanced Penning trap systems.


Project description:

The BASE collaboration conducts high-precision measurements of the fundamental properties of protons and antiprotons with single trapped particles in cryogenic Penning-trap systems at liquid helium temperature (4.2 K).

Magnetic field fluctuations, such as those imposed by the operation of the antiproton decelerator facility of CERN, limit the sensitivity in comparing particle/antiparticle properties as test of the Standard Model of particle physics.

The goal of the BASE collaboration is to relocate antiproton precision measurements from the antiproton decelerator of CERN into a calm magnetic environment by constructing the world’s first transportable antiproton reservoir.

The successful candidate will participate in the construction and commissioning of the transportable trap system at the University of Mainz in Germany. This involves contributions to the design of the transportable Penning trap system, developing an antiproton transfer beamline and the routines for antiproton extraction and transfer, the development of ultra-sensitive detection systems, as well as the software system to control the experiment.

Afterwards, the project will be relocated to the AD/ELENA facility of CERN in Geneva, Switzerland, where the trap system will be commissioned with antiprotons and the relocation of antiprotons into an offline laboratory will be demonstrated.


Further information and applications:

Inquiries and applications should be sent to Christian Smorra ( or Stefan Ulmer (

Candidates should have (or soon obtain) a masters degree in atomic physics or a related field.

Applications should include an academic curriculum vitae (max. 2 pages), transcripts of degree certificates and grades, a letter of motivation (max. 2 pages) and the contact details of at least two referees.

Applications to this position can be submitted at any time. The call will be closed when the position has been filled with a suitable candidate.



Open PhD Position - BASE CERN

BASE is a high precision Penning trap experiment, dedicated to measure the magnetic moment of the antiproton with a fractional  esolution of at least 200 parts in a trillion, on to compare the antiproton-to-proton charge-to-mass ratios with parts per trillion precision. Such measurements provide stringent tests of the fundamental Charge-Partiy-Time invariance and test matter-antimatter-symmetry with ultra-high precision. To accomplish our goals we perform spectroscopy on single particles stored in advanced cryogenic trap systems. The operation of a cryogenic Penning trap experiment involves a broad range of experimental techniques which are related to the design of high-precision multi-Penning trap systems, ultra low-noise electronics engineering, software development as well as mechanical engineering and cryogenic engineering. Several advanced ion trap based quantum metrology methods have been developed in BASE (see list of publications on this website).  All required techniques are combined to investgate the fundamental laws of physics, by experiments with antimatter at lowest energies and with greatest precision.  

For detailed information on available PhD projects, please contact  

The candidate will be affiliated to the Max Planck Institute for Nuclear Physic at Heidelberg, will be a full-time member of BASE at CERN and will reveice its PhD title from the University of Heidelberg, Germany. The applicant needs to meet the standards to become enroled in the PhD program of the university of Heidelberg (excellent undergraduate record).