Search results for "Quadrupole"
showing 10 items of 460 documents
Characterisation of beam focus quality in biomedical nuclear microscopy: A Fourier optics approach
2009
Abstract The central peak widths of the 2D-autocorrelation function have been investigated as a Figure of Merit (FoM) of focus quality in nuclear microscopy using a quadrupole triplet lens system. The beam focus could be reliably characterised for direct scanning transmission ion microscopy (direct-STIM) images obtained with fluences as small as 5.8 × 10 9 ions cm - 2 which colocalisation tests showed did not introduce significant beam-induced changes in the cells.
Quadrupole splitting of Fe(II) spin crossover compounds study of temperature and pressure dependence and the implication for the interaction mechanism
1989
The temperature and pressure dependence of the quadrupole splitting ΔE Q of the 3/2→1/2 nuclear Mossbauer transition of57Fe in the spin crossover compounds [Fe x Zn1−x (2-pic)3]Cl2⋆EtOH and the deuterated analog [Fe x Zn1−x (2-pic-ND2)3] Cl2⋆EtOD (2-pic=2-picolylamine) have been studied. The change of ΔE Q can be linearly related to the defomation of the lattice as observed by X-ray measurements. The dependence of ΔE Q on temperatureT, pressurep, and the fraction γ of molecules in the electronic high spin state in the pure iron (x=1) compounds is therefore interpreted as a result of the change of the lattice contribution to the electric field gradient (EFG) at the nucleus only. The intrinsi…
The design of a new gas-filled separator at JYFL
2003
Abstract A new gas-filled recoil separator, intended mainly for the study of reaction products in mass region of 100–200 produced in symmetric or nearly symmetric reactions, is under design at the Department of Physics in the University of Jyvaskyla. The separator will be of the type DQQ where a horizontally focusing dipole (D) is followed by a quadrupole (Q) doublet. The bending radius of the dipole magnet will be 1850 mm and the bending angle 50°.
Changes in nuclear structure along the Mn isotopic chain studied via charge radii
2016
The hyperfine spectra of $^{51,53-64}$Mn were measured in two experimental runs using collinear laser spectroscopy at ISOLDE, CERN. Laser spectroscopy was performed on the atomic $3d^5\ 4s^2\ ^{6}\text{S}_{5/2}\rightarrow 3d^5\ 4s4p\ ^{6}\text{P}_{3/2}$ and ionic $3d^5\ 4s\ ^{5}\text{S}_2 \rightarrow 3d^5\ 4p\ ^{5}\text{P}_3$ transitions, yielding two sets of isotope shifts. The mass and field shift factors for both transitions have been calculated in the multiconfiguration Dirac-Fock framework and were combined with a King plot analysis in order to obtain a consistent set of mean-square charge radii which, together with earlier work on neutron-deficient Mn, allow the study of nuclear struc…
57Co emission studies of cupric oxide
1990
Results on the incorporation, valence and spin states of Fe(Co) in CuO (with reference to similar studies on high temperature superconductors) and coupling of the Fe(Co) moment to the Cu magnetism in CuO are presented. Freshly prepared57Co: CuO shows two quadrupole doublets D1 and D2 withQ.S. of 2.49 and 1.52,I.S. of 0.35 and 0.70 mm/s and relative abundance of 74% and 26%, respectively at room temperature, the abundance being dependent on time in a sample exposed to ambient conditions and reaching 38 to 62% fifteen months after preparation. Below,TN=2251K, a typical combined magnetic-quadrupole interaction pattern is observed with a single saturation magnetic hfs of 25.6 T, central shift o…
A novel scheme for a highly selective laser ion source
2003
A new type of resonance ionization laser ion source, which shall combine the advantages of a laser ion source with those of an ion trap, is proposed. The primary purpose of such a laser ion source trap, which is based on a gas-filled linear radio-frequency quadrupole ion trap system, is the decoupling of evaporation and ionization processes. Furthermore optimum temporal control on the generated ion bunch is obtained. Both effects will lead to a significantly increased isobaric selectivity and ion beams of low emittance. A large variety of operational modes, ranging from quasi-dc to microseconds-bunched radioactive ion beams with variable pulse width and repetition rate, can be chosen freely…
Optical polarization of neutron-rich sodium isotopes and β-NMR measurements of quadrupole moments
1996
The nuclear quadrupole moments of neutron-rich sodium isotopes are being investigated with the help of in-beam polarization by optical pumping in combination with $\beta$-NMR techniques. First measurements have yielded the quadrupole splittings of NMR signals in the lattice of LiNbO$_{3}$ for the isotopes $^{26}$Na, $^{27}$Na and $^{28}$Na. Interaction constants and ratios of the electric quadrupole moments are derived. In view of future experiments, $\beta$-decay asymmetries for the sequence of isotopes up to the $N$=20 neutron shell closure, $^{26-31}$Na, have been measured.
Nuclear moments and charge radii of rare-earth isotopes studied by collinear fast-beam laser spectroscopy
1983
The collinear fast-beam laser technique is being used to measure systematically hyperfine structures and isotope shifts of unstable nuclides in the rare-earth region. This brief report gives a general survey of the results obtained for the even-Z elements64Gd,66Dy,68Er and70Yb, with emphasis on the nuclear spins and moments. They allow a rather complete mapping of the single-particle structure and the development of nuclear deformation in the N > 82 region. The spins, magnetic moments and spectroscopic quadrupole moments of159–169Yb are presented in detail.
Pairing-quadrupole interplay in the neutron-deficient tin nuclei: First lifetime measurements of low-lying states in 106,108Sn
2020
The lifetimes of the low-lying excited states 2(+) and 4(+) have been directly measured in the neutron-deficient Sn-106,Sn-108 isotopes. the nuclei were populated via a deep-inelastic reaction and the lifetime measurement was performed employing a differential plunger device. the emitted gamma rays were detected by the AGATA array, while the reaction products were uniquely identified by the VAMOS++ magnetic spectrometer. Large-Scale Shell-Model calculations with realistic forces indicate that, independently of the pairing content of the interaction, the quadrupole force is dominant in the B(E2; 2(1)(+) -> 0(g.s)(+)) values and it describes well the experimental pattern for Sn104-114 ; the B…
Laser spectroscopy and the properties of light nuclei near the neutron drip line
1993
The interesting nuclear structure phenomena observed in some light nuclei at the neutron drip line suggest the measurement of basic ground state properties such as spins, magnetic moments and electric quadrupole moments. Here it will be discussed what experiments are presently feasable using laser spectroscopy. For the outstanding example of a “halo” nucleus,11Li, the development of a technique combining β-asymmetry detected optical pumping in a fast beam with NMR spectroscopy has yielded pertinent results, the most recent of which is an experimental value of the nuclear quadrupole moment.