0000000000504627
AUTHOR
Joonas Ojala
Testing of the SPEDE conversion electron spectrometer at ISOLDE
Työssä testattiin uutta SPEDE-ilmaisinta CERNin ISOLDE-laboratorion MINIBALLkoeasemalla, jossa selvitetään ytimien rakenteita käyttämällä radioaktiivia suihkuja. Ilmaisimen testauksessa käytettiin radioaktiivisia Bi-207 ja Hg-191 lähteitä. SPEDE-ilmaisimella pystytään havaitsemaan sisäisen konversion elektroneja. Ytimen viritystilan purkautumisessa sisäinen konversio on kilpaileva prosessi tavanomaisemmalle γ-emissiolle. Sisäistä konversiota tutkimalla saadaan selvitettyä ytimen rakenteen ominaisuuksia kuten esimerkiksi E0-siirtymät ytimissä. SPEDE-ilmaisin mahdollistaa samanaikaiset γ- ja elektronispektrometriset mittaukset MINIBALL-koeasemalla. Työssä käytettiin kokeellisten mittaustulost…
Reassigning the shapes of the 0+ states in the 186Pb nucleus
Across the physics disciplines, the 186Pb nucleus is the only known system, where the two first excited states, together with the ground state, form a triplet of zero-spin states assigned with prolate, oblate and spherical shapes. Here we report on a precision measurement where the properties of collective transitions in 186Pb were determined in a simultaneous in-beam γ-ray and electron spectroscopy experiment employing the recoil-decay tagging technique. The feeding of the 0+2 state and the interband 2+2→2+1 transition have been observed. We also present direct measurement of the energies of the electric monopole transitions from the excited 0+ states to the 0+ ground state. In contrast to…
Observation of the proton emitter 116,57La59
The quantum tunneling and emission of a single constituent nucleon provide a beautifully simple and unique window into the complex properties of atomic nuclei at the extreme edge of nuclear existence. In particular, for odd-odd proton emitting nuclides, the associated decay energy and partial half-life can be used to probe the correlations between the valence neutrons and protons which have been theoretically predicted to favour a new type of nuclear superfluidity, isoscalar neutron-proton pairing, for which the experimental “smoking gun" remains elusive. In the present work, proton emission from the lanthanum isotope 11657La59, 23 neutrons away from the only stable isotope 13957La82, is re…