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Trap assisted spectroscopy and mass measurements at ISOLTRAP


The present structure of the Universe and the paths of element formation are to a large extent determined by ground and isomeric-state properties of nuclei. Ion traps are versatile instruments, successfully applied at radioactive-beam facilities, which con tribute to our understanding of these nuclear properties, e.g. by measuring nuclear masses and charge radii, studying electron-neutrino correlations in beta-decay, or testing the unitarity of the CKM quark-mixing matrix. One prominent example is the ISOLTR AP Penning trap experiment at ISOLDE/CERN, where masses of over 300 short-lived nuclei have been measured with a relative uncertainty reaching 0.01ppm. Being unique as a fingerprint, these masses contribute to stringent tests of nuclear structure and astro physical models, e.g. concerning new magic numbers or the nucleosynthesis of the elements, and even tests of the Standard Model with respect to weak interaction.

The TASMATI project has the objective to enhance the experimental setup and to establish a novel and more versatile research environment at ISOLTRAP. The first part will improve conditions for beta- and gamma- decay studies. Since presently many experiments suffer from isobaric and even isomeric contaminants, purification in a trap will allow overcoming this problem. For this purpose a compact tape-station system will be implemented behind the last experimental trap. The second part aims at a better understanding of the nuclear halo systems by laser spectroscopy measurements on Be isotopes (with the highlight: one neutron-halo nucleus 11Be). The cooling, purifying and trapping of these nuclei will improve experimental conditions and reduce errors. Another, smaller development will allow to measure the masses of other neutron-halo nuclei 6,8He (and la ter 11Li,11Be), which requires modifications to the cooling process.

Call for proposal

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Route De Meyrin 385
Geneva 23