Accurate mass measurements on neutron-deficient krypton isotopes

soumis à Nuclear Physics AThe masses of $^{72-78,80,82,86}$Kr were measured directly with the ISOLTRAP Penning trap mass spectrometer at ISOLDE/CERN. For all these nuclides, the measurements yielded mass uncertainties below 10 keV. The ISOLTRAP mass values for $^{72-75}$Kr outweighed previous results obtained by means of other techniques, and thus completely determine the new values in the Atomic-Mass Evaluation. Besides the interest of these masses for nuclear astrophysics, nuclear structure studies, and Standard Model tests, these results constitute a valuable and accurate input to improve mass models. In this paper, we present the mass measurements and discuss the mass evaluation for these Kr isotopes

Status of HIGISOL a new version equipped with SPIG and electric field guidance

Matière Nucléair

Mass measurement on the rp-process waiting point "7"2Kr

The mass of one of the three major waiting points in the astrophysical rp-process "7"2Kr was measured for the first time with the Penning trap mass spectrometer ISOLTRAP. The measurement yielded a relative mass uncertainty of #delta#m/m=1.2 x 10"-"7 (#delta#m=8 keV). Other Kr isotopes, also needed for astrophysical calculations, were measured with more than one order of magnitude improved accuracy. We use the ISOLTRAP masses of"7"2"-"7"4Kr to reanalyze the role of the "7"2Kr waiting point in the rp-process during X-ray bursts. (orig.)Available from TIB Hannover: RO 801(04-16) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Precision half-life and Q-value measurement of the super-allowed beta emitter (30)S

The b \beta -decay half-life and the ground-state-to-ground-state Q EC -value of 30S were measured with a relative precision of 14 and 2 parts in 104, respectively. The half-life measurement yields a value of 1175.9(17)ms which is in agreement with previous measurements but has a precision that is better by a factor of three. The new super-allowed Q EC -value 5464.32(20)keV is 20 times more precise and slightly larger than the previously adopted value. The experiment was performed at the IGISOL facility at the Accelerator Laboratory of the University of Jyväskylä.This work was supported in part by the Conseil Regional d’Aquitaine. We also acknowledge support from the Academy of Finland under the Finnish Center of Excellence Programme 2006-2011 (Project No. 213503, Nuclear and Accelerator Based Physics Programme at JYFL).Peer Reviewe

Fission yield measurements at IGISOL

The fission product yields are an important characteristic of the fission process. In fundamental physics, knowledge of the yield distributions is needed to better understand the fission process. For nuclear energy applications good knowledge of neutroninduced fission-product yields is important for the safe and efficient operation of nuclear power plants. With the Ion Guide Isotope Separator On-Line (IGISOL) technique, products of nuclear reactions are stopped in a buffer gas and then extracted and separated by mass. Thanks to the high resolving power of the JYFLTRAP Penning trap, at University of Jyväskylä, fission products can be isobarically separated, making it possible to measure relative independent fission yields. In some cases it is even possible to resolve isomeric states from the ground state, permitting measurements of isomeric yield ratios. So far the reactions U(p,f) and Th(p,f) have been studied using the IGISOL-JYFLTRAP facility. Recently, a neutron converter target has been developed utilizing the Be(p,xn) reaction. We here present the IGISOL-technique for fission yield measurements and some of the results from the measurements on proton induced fission. We also present the development of the neutron converter target, the characterization of the neutron field and the first tests with neutron-induced fission