0000000000470287
AUTHOR
U. C. Bergmann
showing 19 related works from this author
Proton dripline studies at ISOLDE: 31Ar and 9C
2002
In this contribution examples of the application of new technologies to disentangle the mechanism of $\beta$-delayed multiparticle emission are given. In particular the mechanism of $\beta$2p-emission from $^{31}$Ar has been resolved and proved to be sequential, a preview of $^{9}$C-decay data is discussed.
Spectroscopy at the drip line: the case of 31Ar
2003
The beta decay of exotic nuclei is directly connected to many different and highly relevant issues. While along the years a hundred of nuclei have been identified as beta delayed proton (β-p) emitters only eight have been found to be β-2p emitters and the β-3p decay mode although energetically allowed has so far not been observed [1].
On-line yields obtained with the ISOLDE RILIS
2003
The ISOLDE resonance ionization laser ion source (RILIS) allows to ionize efficiently and selectively many metallic elements. In recent yield surveys and on-line experiments with the ISOLDE RILIS we observed 23–34 Mg, 26–34 Al, 98–132 Cd, 149 Tb, 155–177 Yb, 179–200 Tl, 183–215 Pb and 188–218 Bi. The obtained yields are presented together with measured release parameters which allow to extrapolate the release efficiency towards more exotic (short-lived) nuclides of the same elements. 2002 Elsevier Science B.V. All rights reserved.
New information on β-delayed neutron emission from Be-12, Be-14
1999
17 pages, 3 tables, 5 figures, 1 appendix.-- PACS nrs.: 23.40.Hc; 27.20.+n.
New information on 12C states from the decays of 12N and 12B
2003
Abstract The properties of states in 12 C above the 3α-threshold are of high current interest for nuclear astrophysics and for the nuclear many-body problem in general. We have initiated a series of experiments aimed at elucidating this region by using the β-decays of 12 N and 12 B. By applying the ISOL method for producing these radioactive isotopes, in combination with modern segmented charged particle detectors, our approach has significant advantages over previous studies of this region.
β-decay of22O
2005
A mass-separated 12 C 22 O molecular ion beam from the ISOLDE facility was used to study the decay of neutron-rich 22 O. The experimental results were compared with the results from an earlier experiment and predictions by shellmodel calculations using various effective interactions. The mechanism leading to the vanishing decay strength to the first 1 + level of the 22 F nucleus, predicted with the USD effective interaction but not supported by the experimental data, is analysed.
Two-proton emission in the decay of Ar-31
1998
18 pages, 7 figures, 2 tables.-- PACS nrs.: 23.40.Hc; 27.30.+t.
Light exotic isotopes: recent beam developments and physics applications at ISOLDE
2002
This paper is divided in three parts: (i) the measurement of yields and decay losses of Li and Be isotopes released from a thin foil tantalum target at the CERN/ISOLDE PS-Booster; (ii) results from beta-decay experiments on Be-12 and Be-14, an improved half-life of 21.49(3) ms has been obtained for Be-12; (iii) the beta-decay of C-9. An outline of the analysis procedure to determine the branching at high excitation energies is given. The ground-state branch has been determined to 54.1(15)%.
News on 12C from beta-decay studies
2004
We discuss the importance of the spectroscopic properties of the resonances of 12C just above the 3α-threshold, and review the existing experimental information of this region with emphasis on O+ and 2+ states. A new experimental approach for studying the β-decays of 12B and 12N is presented based on techniques developed in the context of Radioactive beam (rare isotope) physics. Finally preliminary results from an ongoing analysis of two recent experiments are given. © 2004 Published by Elsevier B.V.
Investigation of the Li9+H2→Li8+t reaction at REX-ISOLDE
2006
The one-neutron transfer reaction Li-9 + H-2 -> Li-8 + t has been investigated in an inverse kinematics experiment by bombarding a deuterated polypropylene target with a 2.36 MeV/u Li-9 beam from the post-accelerator REX-ISOLDE at CERN. Excitation energies in Li-8 as well as angular distributions of the tritons were obtained and spectroscopic factors deduced. (c) 2006 Elsevier B.V. All rights reserved.
The β2p decay mechanism of Ar
2000
We have measured the beta-decay of Ar-31 with a high granularity setup sensitive to multiparticle decay branches. Two-proton emission is observed from the isobaric analog state in Cl-31 to the four lowest states in P-29 and furthermore from a large number of states fed in Gamow-Teller transitions. The mechanism of two-proton emission is studied via energy and angular correlations between the two protons. In all cases the mechanism is found to be sequential yielding information about states in S-30 up to 8 MeV excitation energy. Improved data on the beta-delayed one-proton branches together with the two-proton data provide precise information about the beta-strength distribution up to 15 MeV…
Clarification of the Three-Body Decay ofC12(12.71 MeV)
2003
Using $\ensuremath{\beta}$ decays of a clean source of $^{12}\mathrm{N}$ produced at the IGISOL facility, we have measured the breakup of the $^{12}\mathrm{C}$ (12.71 MeV) state into three $\ensuremath{\alpha}$ particles with a segmented particle detector setup. The high quality of the data permits solving the question of the breakup mechanism of the 12.71 MeV state, a longstanding problem in few-body nuclear physics. Among existing models, a modified sequential model fits the data best, but systematic deviations indicate that a three-body description is needed.
Spectroscopy with β2p and β-ν recoil shifts
2002
9 pages, 4 figures.-- Printed version published Apr 22, 2002.
Beta-decay properties of the neutron-rich $^{94-99}$Kr and $^{142-147}$Xe isotopes
2002
Beta-decay half-lives and delayed-neutron emission probabilities of the neutron-rich noble-gas isotopes Kr94-99 and Xe142-147 have been measured at the PSB-ISOLDE facility at CERN. The results are compared to QRPA shell-model predictions and are used in dynamic calculations of r-process abundances of Kr and Xe isotopes. (C) 2002 Elsevier Science B.V. All rights reserved.
Accelerated radioactive beams from REX-ISOLDE
2003
In 2001 the linear accelerator of the Radioactive beam EXperiment (REX-ISOLDE) delivered for the first time accelerated radioactive ion beams, at a beam energy of 2 MeV/u. REX-ISOLDE uses the method of charge-state breeding, in order to enhance the charge state of the ions before injection into the LINAC. Radioactive singly-charged ions from the on-line mass separator ISOLDE are first accumulated in a Penning trap, then charge bred to an A/q < 4.5 in an electron beam ion source (EBIS) and finally accelerated in a LINAC from 5 keV/u to energies between 0.8 and 2.2 MeV/u. Dedicated measurements with REXTRAP, the transfer line and the EBIS have been carried out in conjunction with the first co…
Decay of48-50Ar isotopes
2011
International audience; Information on β-decay properties of neutron-rich 84-05Ar was obtained at the ISOLDE mass-separator facility at CERN using isobaric selectivity. This was achieved by a combination of a plasma-ion source with a cooled transfer line and subsequent mass-separation. Normally, argon beams cannot be mass-separated from intense multi-charged symmetric fission krypton and xenon. Several techniques were used successfully in order to overcome this problem. Implication of the obtained information for a better understanding of the origin of the 48Ca/46Ca isotopic anomaly discovered in inclusions from the Allende meteorite is discussed.
Two-proton decay of the isobaric analogue state of Ar-31
1998
8 pages, 1 table, 4 figures.-- Journal issue title: "Nucleus-Nucleus Collisions".
Low energy reactions with radioactive ions at REX-ISOLDE-the 9Li + 2H case
2005
19 pages, 12 figures, 2 tables.-- PACS nrs.: 25.60.-t; 25.45.-z; 27.20.+n.-- et al. ISOLDE Collaborattion and REX-ISOLDE Collaboration.
Clarification of the Three-Body Decay of 12C (12.71 MeV)
1991
Using β decays of a clean source of 12 N produced at the IGISOL facility, we have measured the breakup of the 12 C (12.71 MeV) state into three α particles with a segmented particle detector setup. The high quality of the data permits solving the question of the breakup mechanism of the 12.71 MeV state, a longstanding problem in few-body nuclear physics. Among existing models, a modified sequential model fits the data best, but systematic deviations indicate that a three-body description is needed. peerReviewed