Properties of a two-second isomer in¹²⁷Ba measured with a new technique of laser spectroscopy

Abstract

The spin, isotope shift and moments for the two-second isomer in '"Ba have been measured with a new ultrasensitive technique of laser spectroscopy. The results are in agreement with the prediction of the particle plus triarial rotor model with E ~= 0.23 and y = 18". RADiOA(3Ti'v'Il-r' ' " ' " B a from "ivlo("S, 2p2n2nj: measured ko:ope shifi and

Laser spectroscopy for nuclear structure physics

“…The sensitivity of the spectroscopy is limited by backgrounds from uncorrelated laser light scatter, photomultiplier dark or radiation-induced counts and light from fast ion collisions with residual-gas molecules. All but the latter can be reduced by, i), coincidence detection of the fluorescent ion [96] or, ii), bunched delivery of ionic ensembles [127]. Non-optical detection of excitations, those not involving the observation of scattered photons, can be realised by virtue of optical pumping combined with stateselective neutralisation [69] or re-ionisation [35,36].…”

“…The downstream detection of a fluorescent ion may be used to tag a photon detection to a limit corresponding to the spectrometers ability to determine the position origin of the emitted photon. Use of a segmented photomultiplier and imaging optics can provide a depth-of-field limited coincidence window of ∼ 20ns [96,228]. The experimental background is solely limited by isobaric contamination of the ion beam causing collisional light or triggering false coincidences.…”