Feb 6 – 8, 2006
CERN
Europe/Zurich timezone

Study of the neutron-rich tellurium isotopes by laser spectroscopy

Feb 7, 2006, 11:30 AM
25m
Council Chamber, 503/1-001 (CERN)

Council Chamber, 503/1-001

CERN

CH-1211 Geneva 23

Speaker

Brigitte Roussiere (Institut de Physique Nucléaire)

Description

Laser spectroscopy gives access to fundamental properties of the ground and rather long-lived isomeric states such as the change in the mean square charge radius ( ) and the nuclear moments. Measurements on tellurium isotopes (Z = 52) can provide reliable information on the shape of nuclei, structure of states, and effects of dynamics. Indeed from A = 115 to 133, all the odd-A Te isotopes exhibit an isomeric state and the measurement of the isomeric shift gives us a direct indication of the influence of the neutron-core coupling on the nuclear deformation. Moreover the determination of the magnetic moments yields information on the structure of the states. In particular the measurements on the neutron-rich tellurium isotopes allow us to study the variation of the kink at N = 82 approaching the proton magic number Z = 50. ISOLDE offers the opportunity for studying the tellurium isotope series over a wide mass range, from the nuclei located near the N = 66 neutron mid-shell to the neutron- rich ones beyond the neutron shell closure at N = 82. In this contribution we will present the laser spectroscopy experiment performed on the neutron-rich tellurium isotopes and the results obtained up to now. The neutron-rich Te isotopes have been produced by the 238U fission induced by 1 GeV protons in a uranium carbide target associated with a hot plasma ion source. The laser spectroscopy measurements have been performed on the 127-136Te ground states and on the 123,125,127,129,131,133Te isomeric states using the COMPLIS (COllaboration for Measurements using a Pulsed Laser Ion Source) setup that allows resonance ionization spectroscopy (RIS) on laser- desorbed atoms. To avoid direct and disturbing ionization of the isobars by the non- resonant step, a three step process had to be used to ionize selectively the tellurium isotopes: 214.35, 591.6 and 1064 nm. Spectroscopic information (isotope shift and hyperfine structure) has been obtained by scanning the first excitation step (the 5p4 3P2  5p3 6s 3S1 optical transition at 214.35 nm) of the RIS process. The analysis of the data is still in progress. However the   values obtained for the even-even isotopes show that the kink at N = 82 remains in Te, i. e. in an isotopic series with a proton number very close to the magic number Z = 50.

Primary author

Brigitte Roussiere (Institut de Physique Nucléaire)

Presentation materials