Future Penning Trap Experiments at GSI FAIR The

Future Penning Trap Experiments at GSI / FAIR – The HITRAP and MATS Projects K. Blaum 1, 2 and F. Herfurth 1 for the HITRAP and MATS Collaboration 1 GSI Darmstadt, 2 Johannes Gutenberg-University Mainz Introduction Motivation and Fields of Application The mass and its inherent connection with Ion traps play an important role not only in high-precision experiments on stable the nuclear and atomic binding energies is particles but also on exotic nuclei. Besides accurate mass measurements they a basic property of a nuclide. Thus, precise have recently been introduced to nuclear decay studies and laser spectroscopy as mass values are important for a variety of well as to tailoring the properties of radioactive ion beams. This broad usage of applications, ranging from nuclear-structure trapping devices at accelerator facilities is based on the manifold advantages of a studies, test of nuclear mass formulas, to three-dimensional ion confinement in well controlled fields: First, the extended tests of the weak interaction, QED, and of observation time is only limited by the half-life of the radionuclide of interest, the Standard Model. The required relative yielding very high precisions for instance for mass measurements. Second, stored accuracy ranges from 10 -5 to below 10 -10 ions can be cooled and manipulated in various ways, even polarization and for stable and short-lived nuclides, which charge breeding of the ions are possible, giving a unique tool in order to prepare most often have half-lives well below 1 s. otherwise impossible experiments. Third, it is possible to create a backing free Substantial progress in Penning trap mass very efficiently, spectrometry has made this method a reducing a number of uncertainty in classical spectroscopic experiments. The prime choice for precision measurements HITRAP and MATS Collaborations propose advanced trapping systems at GSI on stable and rare isotopes. Furthermore, and the future facility FAIR for high-precision mass measurements, tests of QED ion traps can be used advantageously for using highly-charged heavy ions, and decay studies on short-lived radionuclides. precision decay and laser spectroscopy. source of radioactive nuclei and to collect light particles (e- and e+) GSI and FAIR Figure of the proposed Experimental MATS Setup GSI stands for state of the art research on SIS 100/300 radionuclides: ions and radioactive measurements nuclei. FAIR (Facility electron and alpha spectroscopy. The for Antiproton and Ion experimental setup of MATS is a unique is the future of GSI. The FRS future facility is going HESR Super FRS LEB ESR FA CR RESR IR UNILAC NESR different techniques to very short-lived heavy, highly-charged Research) SIS 18 With MATS at FAIR we aim for applying two High-precision and in-trap mass conversion combination of an electron beam ion trap for charge breeding, ion traps for beam to provide ion beams preparation, and a high precision Penning with currently unique trap system for mass measurements and intensity and energy decay studies. Each subsystem is a so intensive versatile tool itself and allows different high- secondary beams - precision experiments resulting in a broad that e. g. bare uranium, exotic nuclei or antiprotons - can be produced for the planned experiments. HITRAP will use the existing GSI facility and the ESR storage ring to decelerate heavy, highly-charged ions. At FAIR physics output. For beam preparation an ion beam cooler and buncher will be used. A magnetic multi-passage spectrometer is implemented for q/A separation of the highly HITRAP will be the core of the low energy ion and antiproton facility FLAIR. -charged ions. For further details see the MATS will be installed at the Low Energy Branch of the Super-FRS at FAIR, Technical Proposal submitted to the FAIR. where radioactive beams with up to 10 000 higher yields than anywhere else will be available. Experiments at HITRAP and MATS The HITRAP project HITRAP will be installed at GSI in order to provide and study bare heavy nuclei or heavy nuclei A number of experiments are planned at HITRAP and MATS using a high-precision Penning trap. Mass measurements with only few electrons at very low energies or even at rest. Highly-charged ions will be performed at both setups using the high accuracy potential and especially at MATS the high sensitivity. A produced by stripping at relativistic energies. Another possibility is the production of radioactive relative mass uncertainty of 10 -9 for radioactive, short lived ions and 10 -11 for stable, highly-charged ions can be nuclei using the fragment separator FRS. After electron cooling and deceleration in the reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT- Experimental Storage Ring ESR the ions are ejected out of the storage ring at 4 Me. V/u and ICR) detection technique on single stored ions. The use of the FT-ICR technique provides true single ion sensitivity. further decelerated in a combination of an IH and RFQ structure. Finally, they are injected into a This is essential to access isotopes that are produced with minimum rates and that very often are the most interesting Penning trap where the ions are cooled to 4 K. From here, the ions can be transferred in a quasi ones. dc or in a pulsed mode to different experimental setups. These are for instance traps to measure In order to test the predictions of quantum-electrodynamics (QED) the g-factor of the bound electron in hydrogen-like the g-factor of the bound electron or the mass of the ion. Other setups are designed to uranium will be measured in a dedicated Penning trap. In turn, these measurements are able to deliver a new access investigate the electronic structure of heavy, highly-charged ions in detail in slow collisions with to fundamental constants, as for instance the mass of the electron or the fine-structure constanta. helium atoms or with surfaces of insulators and semi-conductors. General Information MATS and HITRAP are international collaborations. More than 16 institutes are part of them and cooperate in the design and construction. A letter of intent for the MATS project was submitted in April 2004 to the FAIR committee and approved. A cost review board evaluated recently very positive the financial part of MATS. Already since spring 2004 HITRAP has been an approved midterm project of GSI and construction of the decelerator and the cooler trap have been started in 2005. First experiments at HITRAP are scheduled for 2007. For further information contact: Dr. Klaus Blaum or Dr. Frank Herfurth Address: University of Mainz, Institute of Physics, 55099 Mainz or GSI, 64291 Darmstadt