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Conférences et séminaires » Séminaire présenté par Pierre Delahaye, CNRS/IN2P3-GANIL

Séminaire présenté par Pierre Delahaye, CNRS/IN2P3-GANIL

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ISOL beam R&D for fundamental physics

Par : Pierre Delahaye, CNRS/IN2P3-GANIL
Date : mardi 22 février 11h00 2011 à 11h00
Lieu : IPHC, Salle de Réunion 2e étage du Bâtiment 27

Résumé :
From the 1930’s to the late 1950’s, studies of nuclear beta – decay have played a decisive role for the development of the present theory of the weak interactions. Nowadays, precisions experiments studying nuclear beta-decay complement high energy physics measurements searching for signature of physics beyond the standard model.

Radioactive ion beams produced with the so-called Isotope Separation On Line (ISOL) method have an optical quality which is comparable to this of the stable ion beams. In turn, the ISOL low energy radioactive ion beams can be easily manipulated in electromagnetic traps. The development of such electromagnetic traps for nuclear physics in the past two decades has permitted to reach unprecedented precisions for a variety of spectroscopy measurements : for the mass measurement of radioactive nuclides, for collinear laser spectroscopy, or for new types of experiments studying beta-decay.

At GANIL, the SPIRAL facility delivers radioactive beams of gaseous elements of unique purity and intensity. Since 2005, LPC Caen leads an on-line experiment in the low energy beam lines of SPIRAL aiming at the beta-decay of trapped 6He+ ions. In such pure Gamow Teller decay, the β-γ angular correlation parameter is sensitive to the existence of tensor interactions. During the last two beam-times, enough statistics could be collected to set the lowest limit on such exotic interactions in nuclear beta-decay. The corresponding data is still under analysis. It was recently realized that the setup used for this experiment could additionally be used for the study of the beta-decay of T=1/2 nuclides, contributing to the tests of CVC and of the unitarity of the CKM matrix. Such mirror transitions would advantageously complement the database of the super-allowed 0+ -> 0+ transitions presently used to deduce the highest precision value for Vud, by providing an independent determination of the corrected FT value for Fermi transitions. A number of isotopes candidates for this measurement could be delivered from an upgraded SPIRAL facility, able to produce new beams from more than 20 condensable elements compared to the 7 gaseous ones readily available. Such upgrade, relying on state – of – the – art ionization techniques in hot plasma sources, and of charge breeding for the purpose of post-acceleration, is one of the major directions taken by GANIL in the transition period to SPIRAL 2. The scientific interest for the SPIRAL upgrade has been recently attested in the fields of nuclear astrophysics, nuclear reactions, nuclear structure and tests of fundamental symmetries as developed above, by letters of intent which were submitted to the GANIL Physical Advisory Committee.

In this seminar I’ll present latest results from the LPC trap experiment, the status of the SPIRAL 1 upgrade and in what this upgrade and ISOL beam R&D at SPIRAL and SPIRAL 2 contribute offering unique perspectives for this kind of precision experiments at the present GANIL facility, and for the future DESIR facility at GANIL.

Personne à contacter : Radomira LOZEVA