0000000000641779
AUTHOR
Federica Defranchi Bisso
Experimental study of isomeric intruder ½+ states 197,203At
A newly observed isomeric intruder ½ + state [ T ½ = 3.5 ( 6 ) ms ] is identified in 203 At using a gas-filled recoil separator and fusion-evaporation reactions. The isomer is depopulated through a cascade of E 3 and mixed M 1 / E 2 transitions to the 9 / 2 − ground state, and it is suggested to originate from the π ( s ½ ) − 1 configuration. In addition, the structures above the ½ + state in 203 At and 197 At are studied using in-beam γ -ray spectroscopy, recoil-decay tagging, and recoil-isomer decay tagging methods. The ½ + state is fed from 3 / 2 + and 5 / 2 + states, and the origin of these states are discussed. peerReviewed
Determination of the fission half-life for the isotope 250No
My Master Thesis is titled “Determination of the fission half-life for the isotope 250No”. The data I analyse in this work were collected in an experiment run in April, 2015, at the accelerator laboratory of the University of Jyväskylä. The Physics motivation for the experiment is explained in my thesis, as well as the involved theoretical background. This isotope was previously proven to decay via spontaneous fission. Also an isomeric state was found. The question I give an answer to in my work is whether the isomeric state fissions directly or it gamma-decays to the ground state, which then fissions itself. Besides both half-lives (for the ground state and the isomeric state) were calcula…