Search results for "Quadrupole"
showing 10 items of 460 documents
The FRS Ion Catcher
2013
At the FRS Ion Catcher at GSI, projectile and fission fragments are produced at relativistic energies, separated in-flight, range-focused, slowed down and thermalized in a cryogenic stopping cell. A multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) is used to perform direct mass measurements and to provide an isobarically clean beam for further experiments, such as mass-selected decay spectroscopy. A versatile RF quadrupole transport and diagnostics unit guides the ions from the stopping cell to the MR-TOF-MS, provides differential pumping, ion identification and includes reference ion sources. The FRS Ion Catcher serves as a test facility for the Low-Energy Branch of the Sup…
Charge radii of neon isotopes across the sd neutron shell
2011
We report on the changes in mean square charge radii of unstable neon nuclei relative to the stable Ne-20, based on the measurement of optical isotope shifts. The studies were carried out using collinear laser spectroscopy on a fast beam of neutral neon atoms. High sensitivity on short-lived isotopes was achieved thanks to nonoptical detection based on optical pumping and state-selective collisional ionization, which was complemented by an accurate determination of the beam kinetic energy. The new results provide information on the structural changes in the sequence of neon isotopes all across the neutron sd shell, ranging from the proton drip line nucleus and halo candidate Ne-17 up to the…
Off-line commissioning of the ISOLDE cooler
2007
International audience; Among the multiple progresses in radioactive ion beam (RIB) manipulation for physics experiments, the beam cooling and bunching in gas-filled RF traps has become a widely used technique. It is particularly well adapted to precision experiments, such as Penning trap mass spectrometry or collinear laser spectroscopy. At ISOLDE, an rf quadrupole cooler and ion buncher (RFQCB) has been designed and developed to deliver radioactive beams of improved quality among most of the on-line experiments. The results of the first off-line tests have shown that high transmission efficiencies could be achieved with different RIBs of alkali metals, as it was expected. During the later…
Laser spectroscopy of radioactive lead and thallium isotopes
1990
By collincar fast beam laser spectroscopy hyperfine structure and isotope shift have been measured of neutron deficient radioactive isotopes of lead (190Pb,191Pb,192Pb,193Pb,194Pb,195Pb,196Pb,197Pb) and thallium (188Tl190Tl,191Tl,192Tl,194Tl,196Tl). Therefrom nuclear magnetic dipole moments, electric quadrupole moments, changes of the mean square charge radii and deformation parameters are deduced and compared with predictions from theory.
Alpha-decay energies of superheavy nuclei for the Fayans functional
2016
Alpha-decay energies for several chains of super-heavy nuclei are calculated within the self-consistent mean-field approach by using the Fayans functional FaNDF$^0$. They are compared to the experimental data and predictions of two Skyrme functionals, SLy4 and SkM*, and of the macro-micro method as well. The corresponding lifetimes are calculated with the use of the semi-phenomenological formulas by Parkhomenko and Sobiczewski and by Royer and Zhang.
Measurement and simulation of the pressure ratio between the two traps of double Penning trap mass spectrometers
2008
Penning traps are ideal tools to perform high-precision mass measurements. For this purpose the cyclotron frequency of the stored charged particles is measured. In case of on-line mass measurements of short-lived nuclides produced at radioactive beam facilities the ions get in general first prepared and cooled by buffer-gas collisions in a preparation trap to reduce their motional amplitudes and are then transported to a precision trap for the cyclotron frequency determination. In modern Penning trap mass spectrometers both traps are placed in the homogeneous region of one superconducting magnet to optimize the transport efficiency. Because the gas pressure inside the precision trap has to …
Simulation studies of the laser ablation ion source at the SHIPTRAP setup
2020
Hyperfine interactions 241(1), 46 (2020). doi:10.1007/s10751-020-01708-0
Collectivity in the light radon nuclei measured directly via Coulomb excitation
2015
Background: Shape coexistence in heavy nuclei poses a strong challenge to state-of-the-art nuclear models, where several competing shape minima are found close to the ground state. A classic region for investigating this phenomenon is in the region around Z=82 and the neutron midshell at N=104. Purpose: Evidence for shape coexistence has been inferred from α-decay measurements, laser spectroscopy, and in-beam measurements. While the latter allow the pattern of excited states and rotational band structures to be mapped out, a detailed understanding of shape coexistence can only come from measurements of electromagnetic matrix elements. Method: Secondary, radioactive ion beams of Rn202 and Rn…
First Offline Results from the S3 Low-Energy Branch
2022
International audience; We present the first results obtained from the S3 Low-Energy Branch , the gas cell setup at SPIRAL2-GANIL, which will be installed behind the S3 spectrometer for atomic and nuclear spectroscopy studies of exotic nuclei. The installation is currently being commissioned offline, with the aim to establish optimum conditions for the operation of the radio frequency quadrupole ion guides, mass separation and ion bunching, providing high-efficiency and low-energy spatial spread for the isotopes of interest. Transmission and mass-resolving power measurements are presented for the different components of the S3-LEB setup. In addition, a single-longitudinal-mode, injection-lo…
Evolution of nuclear structure in neutron-rich odd-Zn isotopes and isomers
2017
Collinear laser spectroscopy was performed on Zn (Z=30) isotopes at ISOLDE, CERN. The study of hyperfine spectra of nuclei across the Zn isotopic chain, N=33–49, allowed the measurement of nuclear spins for the ground and isomeric states in odd-A neutron-rich nuclei up to N=50. Exactly one long-lived (&