The advanced trapping facility MATS at FAIR

Abstract The number of operating Penning traps at Radioactive Ion Beam facilities has increased in the last decade from just one before 2000, to six in 2008, besides several more under construction or in the commissioning phase, as reflected in several contributions to this special issue. The continuous developments have permitted performing mass measurements with relative mass uncertainties ( δm / m ) of 10 −7 –10 −8 on many isotopes from (every time) more exotic nuclei. This has enlarged the scope of physics one can address in Penning-trap mass spectrometry, and although more developments are going on, and will be pursued during the next years, a limiting factor especially important on addressing very exotic nuclei is the production yield, to be overcome by upgrading existing facilities and building up new ones. This is the motivation to build up MATS at the future Facility for Antiprotons and Ion Research (FAIR) in Darmstadt (Germany). As already stated in the Technical Design Report of the facility, MATS will make use of the most advanced techniques developed more recently, or under development at the existing Penning-trap facilities at RIBs or University laboratories. This article will start giving a brief overview on the physics in reach at existing facilities. Then, the limiting factors for mass measurements on exotic nuclei and the main aspects for going beyond the state-of-art will be discussed to come through the MATS facility. The paper will end presenting some possible candidates for the very first experiments on mass measurements with MATS at FAIR.