Detailed study of the decay of 21Mg Jensen, E. A. M.; Nielsen, S. T.; Andreyev, A. ...
The European physical journal. A, Hadrons and nuclei,
07/2024, Letnik:
60, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Beta-delayed proton and gamma emission in the decay of
21
Mg has been measured at ISOLDE, CERN with the ISOLDE Decay Station (IDS) set-up. The existing decay scheme is updated, in particular what ...concerns proton transitions to excited states in
20
Ne. Signatures of interference in several parts of the spectrum are used to settle spin and parity assignments to highly excited states in
21
Na. The previously reported
β
p
α
branch is confirmed. A half-life of 120.5(4) ms is extracted for
21
Mg. The revised decay scheme is employed to test mirror symmetry in the decay and to extract the beta strength distribution of
21
Mg that is compared with theory.
The CERN-ISOLDE fast tape station Stegemann, S.; Atanasov, D.; Au, M. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
08/2023, Letnik:
541
Journal Article
Recenzirano
Odprti dostop
The employment of a suitable radioactive decay spectroscopy setup is essential for the operation of radioactive ion beam (RIB) facilities. CERN-ISOLDE recently developed a new fast tape station (FTS) ...setup to replace its more than 40 years old predecessor. The new FTS is equipped with several β-detectors, a HPGe-detector, provisions for an α-detector, and constitutes a significant improvement in terms of transport times and detector noise characteristics. Since 2021 it is routinely used as the primary asset for yield determination and quality control of produced RIBs at ISOLDE. We address in this work its technical features and introduce the utilized control system.
Nucleosynthesis in Type I X-ray bursts (XRB) proceeds eventually through the rp-process near the proton drip-line. Several N=Z nuclei act as waiting points in the reaction network chain. ...Astrophysical calculations of XRB light curves depend upon the theoretical modelling of the beta decays of interest, with the N=Z waiting points
64
Ge,
68
Se,
72
Kr,
76
Sr, and their second-neighbours N=Z+2 being key nuclei in this context. We have carried out different experimental campaigns at ISOLDE (CERN) to determine the B(GT) distributions, in the decay of several N=Z, N=Z+2 and their daughters, of particular relevance in rp-process calculations. To this aim the Total Absorption Spectroscopy technique is applied. Here we present results on the beta decay of
64
Ga and the status of the analysis of
64
Ge. Our results provide benchmarks for testing and constraining models under terrestrial conditions that can be used later for predictions in stellar environments.
Half-lives of the low-lying yrast states of 212Po have been measured using the delayed coincidence fast-timing method. We report on the first measurement of the 41+ half-life, as well as a new ...measurement of the 61+ half-life with improved accuracy compared to previous studies. The extracted lifetime of the 41+ and 61+ state have been determined to be 100(14) ps and 1.66(28) ns respectively. With these measurements, precise values are now available for the reduced transition strengths B(E2) of all ground state band levels in 212Po up to the first 8+ state, in particular B(E2; 41+→21+) = 9.4(13) W.u. and B(E2;61+→41+) = 8.7(15) W.u. Comparison of the new available data with an α-clustering model calculation provides evidence that the inclusion of the α-cluster degree of freedom significantly improves agreement with experimental data compared to earlier shell model calculations.
β-decay properties in the Cs decay chain Benzoni, G.; Lică, R.; Borge, M.J.G. ...
Journal of physics. Conference series,
02/2018, Letnik:
966, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The study of the decay of neutron-rich Cs isotopes has two main objectives: on one side β decay is a perfect tool to access the low-spin structures in the daughter Ba nuclei, where the evolution of ...octupole deformed shapes can be followed, while, on the other hand, the study of the gross properties of these decays, in terms of decay rates and branching to delayed-neutron emission, are fundamental inputs for the modelling of the r-process in the Rare-Earth Elements peak. Results obtained at CERN-ISOLDE are discussed within this framework and compared to existing data and predictions from state-of-the-art nuclear models.
Models of the β-delayed neutron emission (βn) assume that neutrons are emitted statistically via an intermediate compound nucleus post β decay. Evidence to the contrary was found in an 134In β-decay ...experiment carried out at ISOLDE CERN. Neutron emission probabilities from the unbound states in 134Sn to known low-lying, single-particle states in 133Sn were measured. The neutron energies were determined using the time-of-flight technique, and the subsequent decay of excited states in 133Sn was studied using γ-ray detectors. Individual βn probabilities were determined by correlating the relative intensities and energies of neutrons and γ rays. The experimental data disagree with the predictions of representative statistical models which are based upon the compound nucleus postulate. Our results suggest that violation of the compound nucleus assumption may occur in β-delayed neutron emission. This impacts the neutron-emission probabilities and other properties of nuclei participating in the r-process. A model of neutron emission, which links the observed neutron emission probabilities to nuclear shell effects, is proposed.
The ROSPHERE γ-ray spectroscopy array Bucurescu, D.; Căta-Danil, I.; Ciocan, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2016, Letnik:
837
Journal Article
Recenzirano
The ROmanian array for SPectroscopy in HEavy ion REactions (ROSPHERE) has been designed as a multi-detector setup dedicated to γ-ray spectroscopy studies at the Bucharest 9MV Tandem accelerator. ...Consisting of up to 25 detectors (either Compton suppressed HPGe detectors or fast LaBr3(Ce) scintillator detectors) together with a state of the art plunger device, ROSPHERE is a powerful tool for lifetime measurements using the Recoil Distance Doppler Shift (RDDS) and the in-beam Fast Electronic Scintillation Timing (FEST) methods. The array's geometry, detectors, electronics and data acquisition system are described. Selected results from the first experimental campaigns are also presented.
A customizable and cost-efficient particle-detection system for transfer experiments at ROSPHERE has been designed and tested. Results from the commissioning experiment employing the 2n-transfer ...reaction 94Zr(18O, 16O)96Zr are presented and discussed. The device allows for an efficient suppression of contributions from fusion-evaporation reactions and an improvement of the peak-to-background ratio by about one order of magnitude. The construction, characteristics, and performance are presented and further developments are outlined.
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