The long-lived xenon isomers 129mXe and 131mXe are of interest for the GAMMA-MRI project, which aims at developing a novel imaging modality based on magnetic resonance of polarized unstable tracers. ...Here, we present the steps leading to and following the production of these two isomers via neutron irradiation of highly-enriched 128Xe and 130Xe gas samples at two high-flux reactors, the High-Flux Reactor (Réacteur à haut flux, RHF) at the Institut Laue-Langevin (ILL) and the MARIA reactor at the National Centre for Nuclear Research (NCBJ). We describe the experimental setups and procedures used to prepare the stable xenon samples, to open the irradiated samples, and to transfer xenon isomers into reusable transport vials. The activity of 129mXe and 131mXe was measured to be in the range of tens of MBq per sample of 0.8(1)mg, and was proportional to thermal neutron flux density. A small activity of unstable contaminants was also visible in the samples, but their level is not limiting for the GAMMA-MRI project’s objectives. In addition, the minimum thermal neutron flux density required to produce 129mXe and 131mXe sufficient for the project could be also determined.
•GAMMA-MRI project - a novel imaging modality.•Gaseous samples preparation for high-flux neutron irradiation.•Successful production of xenon isomers (129mXe and 131mXe) in high-flux nuclear reactors.•Neutron capture cross section for 128Xe and 130Xe in Mauwellian neutron flux.
The magnetic dipole moments (μ) of 209Tlg (N=128) and 207Tlm (N=126) have been measured for the first time using the in-source laser resonance-ionization spectroscopy technique with the Laser Ion ...Source and Trap (LIST) at ISOLDE (CERN). The application of the LIST suppresses the usually overwhelming background of the isobaric francium isotopes and allows access to heavy thallium isotopes with A⩾207. The self-consistent theory of finite Fermi systems based on the energy density functional by Fayans et al. well describes the N dependence of μ for 1/2+ thallium ground states, as well as μ for the 11/2− isomeric states in europium, gold and thallium isotopes. The inclusion of particle-vibration coupling leads to a better agreement between the theory and experiment for μ(Tlg, Iπ=1/2+). It is shown that beyond mean-field contributions to μ cannot be neglected at least for thallium isotopes with Iπ=1/2+.
At CERN-ISOLDE, high-purity radioactive ion beams of 219Fr and 221RaF were investigated with α-decay spectroscopy at the CRIS and ASET experiments in the course of three different experimental ...campaigns. The half-life of 215At, α-decay daughter of 219Fr, is measured to be 36.3(3)9μs, and that of 221Ra was determined to be 26.2(1)6s, both of which are well in line with the trends in this region of the nuclear landscape but at odds with some of the reported literature.
The article describes the commissioning and technical development of the Weak Interaction Studies with 32Ar Decay (WISArD) experiment, installed at the radioactive ion-beam facility ISOLDE/CERN. The ...experiment aims to extend the present limits on scalar and tensor currents in the weak interaction and hence search for physics beyond the Standard Model. The evaluation of these limits relies on measuring the proton energy in beta-delayed proton emission, sensitive to both the beta-neutrino angular correlation coefficient aβν and the Fierz interference term b. The method tries to improve previous studies by considering the positron-proton coincidences when determining the kinematic shift in the energy of the emitted protons. Using this coincidence technique, the aβν and b coefficients will be measured at the per mil level. Simulations were employed to optimize the ion beam transport efficiency and validate proof-of-principle results obtained in November 2018 (Nov2018). Upgrades are ongoing, and we are looking into improvements to the overall performance of the setup.
At CERN-ISOLDE, high-purity radioactive ion beams of
Fr and
RaF were investigated with α-decay spectroscopy at the CRIS and ASET experiments in the course of three different experimental campaigns. ...The half-life of
At, α-decay daughter of
Fr, is measured to be 36.3(3)9μs, and that of
Ra was determined to be 26.2(1)6s, both of which are well in line with the trends in this region of the nuclear landscape but at odds with some of the reported literature.
.
We report on the development and characterization of the first radioactive boron beams produced by the isotope mass separation online (ISOL) technique at CERN-ISOLDE. Despite the long history of ...the ISOL technique which exploits thick targets, boron beams have up to now not been available. This is due to the low volatility of elemental boron and its high chemical reactivity which make the definition of an appropriate production target unit difficult. In addition, the short half-lives of all boron radioisotopes complicate tracer release studies. We report here on dedicated offline release studies by neutron capture and alpha detection done with implanted
10
B in prospective target materials, as well as molecule formation and ionization tests, which suggested the use of multiwalled carbon nanotubes (CNT) as target material and injection of sulfur hexafluoride SF
6
to promote volatile boron fluoride formation. Two target units equipped with an arc discharge electron impact ion source VADIS coupled to a water cooled transfer line to retain non-volatile elements and molecules were subsequently tested online. The measured yield of these first
8
B ISOL beams increases in the series
8
BF
3
<
8
BF
<
8
B
<
8
BF
2
, reaching a maximum yield of
6
.
4
×
10
4
8
BF
2
+
ions per μC of protons.
The main goal of this work is to study the structure of the highest energy states in 8Be populated following the β+-decay and the electron capture (EC) of 8B. With this aim, two experiments were ...performed at ISOLDE-CERN in 2017 and 2018. The first experiment had the aim to resolve the 2+ doublet at 16.6 and 16.9 MeV, in order to study their isospin mixing. The second experiment aimed to determine a value or give an experimental upper limit to the branching ratio of the exotic EC-p decay. In this paper, we present the experimental setups and we discuss the analysis and present the preliminary results obtained so far.
208Po populated through EC/β+ decay Brunet, M.; Berry, T.A.; Podolyák, Zs ...
Journal of physics. Conference series,
12/2020, Letnik:
1643, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The structure of 208Po resulting from the EC/β+ decay of 208At was studied at CERN's ISOLDE Decay Station (IDS). The high statistics afforded by the high yield of 208At and the high efficiency HPGe ...clusters at the IDS allowed for greater insight into lower intensity transitions and thus significant expansion of the 208Po level scheme. Furthermore, investigation into the isomeric state yielded a new half life 377(9) ns in addition to uncovering new transitions populating the state.
Study of exotic decay of Cs isotope close to the proton drip line Das, P.; Dattaf, Ushasi; Chakraborty, S. ...
27th International Nuclear Physics Conference, INPC 2019,Glasgow, United Kingdom,2019-07-29 - 2019-08-02,
12/2020, Letnik:
1643, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The neutron-deficient 115Cs was produced at ISOLDE, CERN by spallation reaction using 1.4 GeV proton on LaC2 target. The exotic decay modes were studied by using a charged particle array (DSSD and ...pad detectors) and a γ-detector array (four Clovers) at the ISOLDE decay station (IDS). In this report, results on observed β-delayed particle emission from 115Cs, a nucleus close to proton drip line, is presented. By measuring the time distribution in the delayed proton spectrum, the half-life of the ground state of 115Cs was extracted. The obtained half-life is in agreement with previous reported value. For the first time, the p-unbound states of 115Xe, obtained by measuring beta-delayed protons from 115Cs is reported.
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