High-accuracy mass determination of unstable cesium and barium isotopes

Abstract

Direct mass measurements of short-lived Cs and Ba isotopes have been performed with the tandem Penning trap mass spectrometer ISOLTRAP installed at the online isotope separator ISOLDE at CERN. Typically, a mass resolving power of 600 000 and an accuracy of m 13 keV have been obtained. The masses of 123;124;126 Ba and 122m Cs were measured for the rst time. A least-squares adjustment has been performed and the experimental masses are compared with theoretical ones, particularly in the frame of a macroscopic-microscopic model.

First Results from the CARIBU Facility: Mass Measurements on ther-Process Path

“…Also listed in Table I are comparisons to other direct measurements. The agreement for the 7 nuclides measured by both the CPT and ISOLTRAP [25][26][27][28] is excellent. The 19 common ground-state measurements with JYFLTRAP [24] are mostly in agreement, but with 2 masses-of 133 Te and 140 Te-disagreeing by 5.6 and 3.2 σ, respectively.…”

“…Because β decay is the process that moves material to higher proton numbers, the β-decay lifetimes of the nuclei involved determine how quickly the heaviest elements can be reached. The balance between neutron capture (n, γ) and photodissociation (γ, n) reactions determines the distribution of isotope populations within [23] and other direct measurements from JYFLTRAP [24], ISOLTRAP [25][26][27][28], and the FRS-ESR ring [29,30]. In the difference columns, uncertainties in parentheses are the combined uncertainties, and those in braces are of the sources cited.…”

High-accuracy mass spectrometry of fission products with Penning traps

“…During recent years, masses of around fission fragments have been measured with Penning traps. Most of the measurements have been performed at JYFLTRAP [40][41][42][43][44][45][46][47][48][49][50] and ISOLTRAP [51][52][53][54][55][56][57][58][59][60][61][62][63]8] facilities. Some nuclei in the relevant region have also been studied at CPT [64,65], LEBIT [66] and TITAN [23].…”

“…Three selected models that gave the best agreement were the Finite Range Droplet Model (FRDM95 [73]), which is a microscopic-macroscopic model applying shell model corrections onto liquid-drop model, the model by Duflo and Zuker [74], which separates the Hamiltonian into monopole and multipole terms, and a mean-field model HFB-21 [75]. Comparison of ISOLTRAP [52,8] and CPT data [64,65]. The updated mass values had the biggest impact on the root-mean-square deviation (σ rms ) of the model HFB-21, which was decreased by around 100 keV compared to the dataset based on AME03 values.…”

Rich band structure and multiple long-lived isomers in the odd-odd Cs118 nucleus

“…The lightest odd-odd Cs nucleus with known spectroscopic information is the proton emitter 112 Cs [9,10], in which five firm and two tentative transitions have been identified and assigned to the π h 11/2 ⊗ νh 11/2 configuration based on systematics [5]. The low-lying states of Cs nuclei have been studied over many years, also exploiting the high yields of radioactive beams of Cs isotopes at ISOL facilities [11,12]. Two long-lived isomers have been identified in 118 Cs, the nucleus studied in the present work, one with T 1/2 = 14(2) s and low spin I = 2, and the other with T 1/2 = 17(3) s and high spin I = (6, 7, 8) [12,13].…”