A new technique for measuringgfactors of excited states in fission fragments using large arrays of Ge detectors

Abstract

The theory behind a new, three-dimensional analysis technique for the measurement of time-integral, perturbed angular correlation (IPAC) functions is presented. The new technique is described in relation to existing methods and in terms of its specific application to a large, Ge-detector array. The effective application of the new technique is demonstrated with results from an experiment where the g factors of excited states in 252Cf, secondary fission fragments were determined. A 252Cf source, sandwiched between two iron foils and placed in a saturated magnetic field at the centre of the Gammasphere detector array, was used to make IPAC measurements of prompt γ rays in order to deduce Larmor precession angles of stopped fragments in iron. The g factor of the Iπ = 2+ state in 104Mo was thus measured to be g = +0.248(22). This new measurement shows a factor-of-5 improvement to the precision which has previously been attained in more conventional experiments.

Near-yrast, medium-spin, excited states ofRb91,Rb93Simpson1, Urban2, Sieja3 et al. 2010Phys. Rev. C354150View full textAdd to dashboardCite

“…These sources were placed at the center of the EUROGAM-II [12] and Gammasphere arrays, respectively (see Refs. [13,25], and [26] for more details on these experiments). The 248 Cm data set allowed angular correlations between delayed transitions to be measured.…”

“…The results of this experiment were supplemented by data from measurements of γ rays emitted following the spontaneous fission of 248 Cm and 252 Cf sources, performed with the EUROGAM-II [12] and Gammasphere detector arrays, respectively (see Ref. [13] for more information on the Gammasphere experiment). Data from the latter experiment have allowed the excitation scheme of 91 Rb to be extended.…”

Shape coexistence in the odd-odd nucleus Y98 : The role of the g9/2 neutron extruder

“…The results from the measurement of 248 Cm fission, have been verified and extended in a measurement of γ rays following spontaneous fission of 252 Cf, performed using the Gammasphere array of Ge detectors at Argonne National Laboratory (see Ref. [18] for more information on the experiment). In the measurement about 1.2×10 11 triple coincidences were collected, an order of magnitude more than in the measurement of 248 Cm fission.…”

Parity-doublet structure in the La9057147 nucleus

“…The present data has been obtained from a measurement of high-fold γ-ray cascades following spontaneous fission of 252 Cf, performed using the Gammasphere array of Anti-Compton Spectrometers (ACS) [20]. We have analyzed prompt-γ, triple coincidences using analysis techniques described in Refs.…”