Search results for "radioactive ion beams"
showing 10 items of 35 documents
Trap-assisted spectroscopy with REXTRAP
2007
International audience; As one of the fashionable techniques for nuclear spectroscopy experiments, the beam manipulation in gas-filled Penning traps permits the accurate measurement of some of the ground state properties of exotic nuclides. It was recently applied using REXTRAP for the measurement of the half-life of 38Ca, one of the 0+ → 0+ β-decaying nuclide of interest for the determination of the Ft value for super-allowed transitions, and the test of the unitarity of the CKM matrix. The experimental setup and the original method of beam purification adopted for this measurement is presented.
New exotic beams from the SPIRAL 1 upgrade
2018
Since 2001, the SPIRAL 1 facility has been one of the pioneering facilities in ISOL techniques for reaccelerating radioactive ion beams: the fragmentation of the heavy ion beams of GANIL on graphite targets and subsequent ionization in the Nanogan ECR ion source has permitted to deliver beams of gaseous elements (He, N, O, F, Ne, Ar, Kr) to numerous experiments. Thanks to the CIME cyclotron, energies up to 20 AMeV could be obtained. In 2014, the facility was stopped to undertake a major upgrade, with the aim to extend the production capabilities of SPIRAL 1 to a number of new elements. This upgrade, which is presently under commissioning, consists in the integration of an ECR booster in the…
Design, construction and cooling system performance of a prototype cryogenic stopping cell for the Super-FRS at FAIR
2015
A cryogenic stopping cell for stopping energetic radioactive ions and extracting them as a low energy beam was developed. This first ever cryogenically operated stopping cell serves as prototype device for the Low-Energy Branch of the Super-FRS at FAIR. The cell has a stopping volume that is 1 m long and 25 cm in diameter. Ions are guided by a DC field along the length of the stopping cell and by a combined RF and DC fields provided by an RE carpet at the exit-hole side. The ultra-high purity of the stopping gas required for optimum ion survival is reached by cryogenic operation. The design considerations and construction of the cryogenic stopping cell, as well as some performance character…
Characterization of a cryogenic ion guide at IGISOL
2012
A small volume cryogenic ion guide has been characterized at the IGISOL facility, Jyvaskyla, as a prototype to verify whether there are any major obstacles to the use of high-density cryogenic helium gas for the stopping and extraction of high-energy ions from a large volume cryogenic ion catcher. The expected temperature scaling of the mass flow through the ion guide has been confirmed, showing that for the same helium density, the differential pumping requirements are less stringent for cryogenic operation. At 90 K a clear reduction in the mass-analyzed impurities is achieved, although lower temperatures are required to freeze out oxygen and nitrogen. This is supported by the reduction in…
Production of zero energy radioactive beams through extraction across superfluid helium surface
2003
A radioactive Ra-223 source was immersed in superfluid helium at 1.2-1.7 K. Electric fields transported recoiled Rn-219 ions in the form of snowballs to the surface and further extracted them across the surface. The ions were focussed onto an aluminium foil and alpha particle spectra were taken with a surface barrier spectrometer. This enabled us to determine the efficiency for each process unambiguously. The pulsed second sound wave proved effective in enhancing the extraction of positive ions from the surface. Thus we offer a novel method for study of impurities in superfluid helium and propose this method for production of zero energy nuclear beams for use at radioactive ion beam facilit…
Collectivity in ${}^{\mathrm{196,198}}$Pb isotopes probed in Coulomb-excitation experiments at REX-ISOLDE
2017
The neutron-deficient ${}^{\mathrm{196,198}}$Pb isotopes have been studied in Coulomb-excitation experiments employing the Miniball γ-ray spectrometer and radioactive ion beams from the REX-ISOLDE post-accelerator at CERN. The reduced transition probabilities of the first excited 2+ states in 196Pb and 198Pb nuclei have been measured for the first time. Values of $B(E2)={18.2}_{-4.1}^{+4.8}$ W.u. and $B(E2)={13.1}_{-3.5}^{+4.9}$ W.u., were obtained, respectively. The experiment sheds light on the development of collectivity when moving from the regime governed by the generalised seniority scheme to a region, where intruding structures, associated with different deformed shapes, start to com…
Cryogenic helium as stopping medium for high-energy ions
2008
We have investigated the survival and transport efficiency of Ra-219 ions emitted by a Ra-223 source in high-density cryogenic helium gas, with ionisation of the gas induced by a proton beam. The combined efficiency of ion survival and transport by an applied electric field was measured as a function of ionisation rate density for electric fields up to 160 V/cm and for three temperature and density combinations: 77 K, 0.18 mg/cm(3), 10 K, 0.18 mg/cm(3) and 10 K, 0.54 mg/cm(3). At low beam intensity or high electric field, an efficiency of 30%, is obtained, confirming earlier results. A sharp drop in efficiency is observed at a "threshold" ionisation rate density which increases with the squ…
A linear radiofrequency ion trap for accumulation, bunching, and emittance improvement of radioactive ion beams
2000
An ion beam cooler and buncher has been developed for the manipulation of radioactive ion beams. The gas-filled linear radiofrequency ion trap system is installed at the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. Its purpose is toaccumulate the 60-keV continuous ISOLDE ion beam with high efficiency and to convert it into low-energy low-emittance ion pulses. The efficiency was found to exceed 10\,\% in agreement with simulations. A more than 10-fold reduction of the ISOLDE beam emittance can be achieved. The system has been used successfully for first on-line experiments. Its principle, setup and performance will be discussed. An ion beam cooler and buncher has been developed fo…
Mirror energy differences above the 0f7/2 shell: First γ-ray spectroscopy of the Tz = −2 nucleus 56Zn
2021
5 pags., 4 figs.
Radioactive ion beams in the region of 100Sn and 78Ni at the NSCL
2004
The regions around the doubly magic nuclei 100 Sn and 78 Ni are of great interest from a nuclear structure standpoint. These nuclei also play a key role in the astrophysical rp- and r-processes, respectively. Recently, nuclei in these regions were studied at the Coupled Cyclotron Facility at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University.