CERN Accelerating science

A high-spin isomer in  
98
 Zr 
 , of half-life 1.9 (2) 𝜇⁢𝑠, has been observed using the Lohengrin mass spectrometer of the high-flux reactor of the Institut Laue-Langevin, Grenoble. The isomer was produced by the thermal-neutron induced fission of  
239
 Pu 
 . Measurements at the spectrometer focal point of 𝛾−𝑡 and 𝛾−𝛾−𝑡, relative to the arrival of a fission fragment, allowed the isomer to be identified and the level scheme constructed. The isomeric state at 6603.3 keV of excitation energy is tentatively assigned a spin and parity of (17−) and is proposed to have a 𝜋⁡(𝑔2
9/2)⁢𝜈⁡(𝑔1
7/2⁡ℎ1
11/2) configuration.