0000000001051900
AUTHOR
J.p. Ramos
showing 13 related works from this author
Production and release of ISOL beams from molten fluoride salt targets
2014
In the framework of the Beta Beams project, a molten fluoride target has been proposed for the production of the required 1013 18Ne/s. The production and extraction of such rates are predicted to be possible on a circulating molten salt with 160 MeV proton beams at close to 1 MW power. As a most important step to validate the concept, a prototype has been designed and investigated at CERN-ISOLDE using a static target unit. The target material consisted of a binary fluoride system, NaF:LiF (39:61 mol.%), with melting point at 649 °C. The production of Ne beams has been monitored as a function of the target temperature and proton beam intensity. The prototype development and the results of th…
Advances in surface ion suppression from RILIS: Towards the Time-of-Flight Laser Ion Source (ToF-LIS)
2016
Abstract We present results from the development towards the Time-of-Flight Laser Ion Source (ToF-LIS) aiming for the suppression of isobaric contaminants through fast beam gating. The capability to characterize high resistance ion sources has been successfully demonstrated. A ninefold selectivity gain has been achieved through suppression of surface ionized potassium, while maintaining >90% transmission for laser-ionized gallium using a thin wall graphite ionizer cavity combined with a fast beam gate. Initial results from the investigation of glassy carbon as a potential hot cavity ion source are presented. Power-cycle tests of a newly designed mount for fragile ion source cavities indicat…
Shape staggering of midshell mercury isotopes from in-source laser spectroscopy compared with density-functional-theory and Monte Carlo shell-model c…
2019
Neutron-deficient Hg177-185 isotopes were studied using in-source laser resonance-ionization spectroscopy at the CERN-ISOLDE radioactive ion-beam facility in an experiment combining different detection methods tailored to the studied isotopes. These include either α-decay tagging or multireflection time-of-flight gating for isotope identification. The endpoint of the odd-even nuclear shape staggering in mercury was observed directly by measuring for the first time the isotope shifts and hyperfine structures of Hg177-180. Changes in the mean-square charge radii for all mentioned isotopes, magnetic dipole, and electric quadrupole moments of the odd-A isotopes and arguments in favor of I=7/2 s…
Enhancing the extraction of laser-ionized beams from an arc discharge ion source volume
2018
© 2018 The Author(s) The Versatile Arc Discharge and Laser Ion Source (VADLIS) is a recently established ion source for the CERN-ISOLDE radioactive ion beam facility. It offers either electron-impact ionization (VADIS-mode) or resonance laser ionization (RILIS-mode). The choice of operating mode depends on the element of interest or the required beam purity. Particle-in-cell simulations using the VSim software show that the ion extraction efficiency of the VADLIS in RILIS-mode can be improved if it is equipped with an insulated extractor plate, to which an optimal voltage can be applied. This enables optimization of the RILIS-mode ion extraction independently of the electron density. Experi…
Dealing with contaminants in Coulomb excitation of radioactive beams
2020
Abstract Data analysis of the Coulomb excitation experiment of the exotic 206Hg nucleus, recently performed at CERN’s HIE-ISOLDE facility, needs to account for the contribution to target excitation due to the strongly-present beam contaminant 130Xe. In this paper, the contamination subtraction procedure is presented.
The LIEBE high-power target: Offline commissioning results and prospects for the production of 100Sn ISOL beams at HIE-ISOLDE
2020
Abstract With the aim of increasing the primary beam intensity in the next generation Radioactive Ion Beam facilities, a major challenge is the production of targets capable of dissipating high beam power, particularly for molten targets. In that context, a direct molten loop target concept was proposed for short-lived isotopes for EURISOL. The circulation of molten metal enables the production of droplets enhancing the radioisotope diffusion. The concept also includes a heat exchanger ensuring thermal equilibrium under interaction with high proton beam power. A target prototype, named LIEBE, has been designed and assembled to validate this concept in the ISOLDE operation environment. The p…
Quadrupole deformation of Xe-130 measured in a Coulomb-excitation experiment
2020
Physical review / C 102(5), 054304 (2020). doi:10.1103/PhysRevC.102.054304
Production of molecular sideband radioisotope beams at CERN-ISOLDE using a Helicon-type plasma ion source
2013
In order to account for the increasing demand for strong molecular beams for nuclear physics experiments at ISOLDE, a new radioactive ion source concept based on an RE discharge in a magnetized plasma was developed at CERN. Experimental studies at the ISOLDE offline separator show that the optimum conditions for CO+ and CO2+ ion production are given when the ion source is operated with He plasma, in line with expectations based on their electron impact ionization cross-sections. At optimum tuning, ionization efficiencies of 2.5% and 4% were measured for CO+ and Ar+, respectively. The capability of the Helicon ion source prototype for ISOL operation was evaluated during two online runs at th…
The upgraded ISOLDE yield database – A new tool to predict beam intensities
2020
At the CERN-ISOLDE facility a variety of radioactive ion beams are available to users of the facility. The number of extractable isotopes estimated from yield database data exceeds 1000 and is still increasing. Due to high demand and scarcity of available beam time, precise experiment planning is required. The yield database stores information about radioactive beam yields and the combination of target material and ion source needed to extract a certain beam along with their respective operating conditions. It allows to investigate the feasibility of an experiment and the estimation of required beamtime. With the increasing demand for ever more exotic beams, needs arise to extend the functi…
In-source laser spectroscopy of dysprosium isotopes at the ISOLDE-RILIS
2019
A number of radiogenically produced dysprosium isotopes have been studied by in-source laser spectroscopy at ISOLDE using the Resonance Ionization Laser Ion Source (RILIS). Isotope shifts were measured relative to $^{152}$Dy in the 4 f$^{ 10}$6s$^{2}$ $^5$I$_8$ (gs) $\rightarrow$ 4 f$^{ 10}$6s6p (8,1)$^8_o$ (418.8 nm$_{vac}$) resonance transition. The electronic factor, F, and mass shift factor, M, were extracted and used for determining the changes in mean-squared charge radii for $^{145m}$Dy and $^{147m}$Dy for the first time. A number of radiogenically produced dysprosium isotopes have been studied by in-source laser spectroscopy at ISOLDE using the Resonance Ionization Laser Ion Source (…
First application of the Laser Ion Source and Trap (LIST) for on-line experiments at ISOLDE
2012
The Laser Ion Source and Trap (LIST) provides a new mode of operation for the resonance ionization laser ion source (RILIS) at ISOLDE/CERN, reducing the amount of surface-ionized isobaric contaminants by up to four orders of magnitude. After the first successful on-line test at ISOLDE in 2011 the LIST was further improved in terms of efficiency, selectivity, and reliability through several off-line tests at Mainz University and at ISOLDE. In September 2012, the first on-line physics experiments to use the LIST took place at ISOLDE. The measurements of the improved LIST indicate more than a twofold increase in efficiency compared to the LIST of the 2011 run. The suppression of surface-ionize…
Blurring the boundaries between ion sources: The application of the RILIS inside a FEBIAD type ion source at ISOLDE
2016
For the first time, the laser resonance photo-ionization technique has been applied inside a FEBIAD-type ion source at an ISOL facility. This was achieved by combining the ISOLDE RILIS with the ISOLDE variant of the FEBIAD ion source (the VADIS) in a series of off-line and on-line tests at CERN. The immediate appli- cations of these developments include the coupling of the RILIS with molten targets at ISOLDE and the introduction of two new modes of FEBIAD operation: an element selective RILIS mode and a RILIS + VADIS mode for increased efficiency compared to VADIS mode operation alone. This functionality has been demonstrated off-line for gallium and barium and on-line for mercury and cadmi…
Quadrupole and octupole collectivity in the semi-magic nucleus 80,206Hg126
2023
The first low-energy Coulomb-excitation measurement of the radioactive, semi-magic, two proton-hole nucleus 206Hg, was performed at CERN’s recently-commissioned HIE-ISOLDE facility. Two γ rays depopulating low-lying states in 206Hg were observed. From the data, a reduced transition strength B(E2; 2+ 1 → 0+ 1 ) = 4.4(6) W.u was determined, the first such value for an N = 126 nucleus south of 208Pb, which is found to be slightly lower than that predicted by shell-model calculations. In addition, a collective octupole state was identified at an excitation energy of 2705 keV, for which a reduced B(E3) transition probability of 30+10−13 W.u was extracted. These results are crucial for understand…