Surface Instabilities on Liquid Oxygen in an Inhomogeneous Magnetic Field

Liquid oxygen exhibits surface instabilities when subjected to a sufficiently strong magnetic field. A vertically oriented magnetic field gradient both increases the magnetic field value at which the pattern forms and shrinks the length scale of the surface patterning. We show that these effects of the field gradient may be described in terms of an ``effective gravity'', which in our experiments may be varied from 1g to 360g.Comment: 4 pages, 5 embedded figures in eps forma

Calculation of production and decay of radioisotopes for future irradiation experiments and ion beam facilities

Abstract.: The design of future radioactive ion beam (RIB) facilites requires the forecast of radio isotope inventory after irradiation. At CERN - ISOLDE, we developed a software that estimates the activity of irradiated materials as a function of time dedicated to radioactive waste management. This tool can also be used for licensing procedures, planning of irradiation experiments and the estimation of yield

Development of High Efficiency Versatile Arc Discharge Ion Source (VADIS) at CERN Isolde

We report here recent developments of Forced Electron Beam Impact Arc Discharge (FEBIAD) ion sources at CERN-ISOLDE. As a result of the propositions to improve the ionization efficiency, two FEBIAD prototypes have been produced and successfully tested in 2008. Off-line studies showed that the 1+ ionization efficiencies for noble gases are 5 to 20 times larger than with the standard ISOLDE FEBIAD ion sources, and reach 60% for Radon, which allowed the identification at ISOLDE of 229Rn, an isotope that had never previously been observed in the laboratory. A factor 3 increase is also expected for the ionization efficiency of the other elements. The experimental and theoretical methodology is presented. The theoretical model which gives precise insights on the processes affecting the ionization is used to design optimal sources for the different chemical classes of the produced isotopes, as already demonstrated for noble gases

The High Resolution Spectrometer at ISOLDE

ISOLDE's HRS (High Resolution isotope Separator) was recommissioned in mid 2000, after a period out of service. Since then, the separator has routinely run with a mass resolution of 3000-4500 and during 2001 it delivered 72% of ISOLDE's radioactive output. A concerted effort has been made to understand the ion optics and optimise performance. In this paper we present an overview of the HRS and investigate the factors which limit the attainable mass resolution: ion-source emittance; optical aberrations; beam instrumentation and magnet stability

Horizontal deflection of single particle in a paramagnetic fluid

This paper describes the horizontal deflection behaviour of a single particle in paramagnetic fluids under a high-gradient superconducting magnetic field. A glass box was designed to carry out experiments and test assumptions. It was found that the particles were deflected away from the magnet bore centre and particles with different density and/or susceptibility settled at a certain position on the container floor due to the combined forces of gravity and magneto-Archimedes as well as lateral buoyant (displacement) force. Matlab was chosen to simulate the movement of the particle in the magnetic fluid, the simulation results were in good accordance with experimental data. The results presented here, though, are still very much in their infancy, which could potentially form the basis of a new approach to separating materials based on a combination of density and susceptibility. Graphical abstract: [Figure not available: see fulltext.

Effects of thermal shocks on the release of radioisotopes and on molten metal target vessels

The ISOLDE pulsed proton beam peak power amounts to 500 MW during the 2.4 ms proton pulse. The fraction of the proton pulse energy deposited in the target material is at the origin of severe thermal shocks. Quantitative measurement of their effect on the release of radioelements from ISOLDE targets was obtained by comparison of release profiles measured under different proton beam settings. The thermal shock induced in liquids (Pb, Sn, La) lead to mechanical failure of ISOLDE molten metal target vessels. Failure analysis is presented and discussed in the light of the response of mercury samples submitted to the ISOLDE beam and monitored by high-speed optical systems

Production yields of noble-gas isotopes from ISOLDE UCx_{x}/graphite targets

Yields of He, Ne, Ar, Kr and Xe isotopic chains were measured from UC$_{x}$/graphite and ThC$_{x}$/graphite targets at the PSB-ISOLDE facility at CERN using isobaric selectivity achieved by the combination of a plasma-discharge ion source with a water-cooled transfer line. %The measured half-lives allowed %to calculate the decay losses of neutron-rich isotopes in the %target and ion-source system, and thus to obtain information on the in-target %productions from the measured yields. The delay times measured for a UC$_x$/graphite target allow for an extrapolation to the expected yields of very neutron-rich noble gas isotopes, in particular for the ``NuPECC reference elements'' Ar and Kr, at the next-generation radioactive ion-beam facility EURISOL. \end{abstract} \begin{keyword} % keywords here, in the form: keyword \sep keyword radioactive ion beams \sep release \sep ion yields \sep ISOL (Isotope Separation On-Line) \sep uranium and thorium carbide targets. % PACS codes here, in the form: \PACS code \sep code \PACS 25.85.Ge \sep 28.60+S \sep 29.25.Rm