0000000000076407
AUTHOR
I. S. Grant
showing 9 related works from this author
First on-line laser spectroscopy of radioisotopes of a refractory element
1999
The first fully on-line isotope shift measurement of a radioactive refractory element is reported. Collinear laser-induced fluorescence measurements were made on the radioactive isotopes ${}^{170,172,173,174}\mathrm{Hf}$ produced with a flux of $2--3\ifmmode\times\else\texttimes\fi{}{10}^{3}$ ions per second from an ion-guide fed isotope separator. The method may be applied to all elements and isomers with lifetimes as short as 1 ms. The systematics of the new charge radii measurements are well reproduced by theory, with the maximum deformation in the chain occurring significantly below the midshell.
The nuclear structure of 229Th
2002
Abstract The γ -rays following the β − decay of 229 Ac have been investigated by means of γ -ray singles and γγ -coincidence measurements using Ge detectors. Multipolarities of 40 transitions in 229 Th have been established by measuring conversion electrons with a mini-orange electron spectrometer. The half-lives of the 146.35, 164.53 and 261.96 keV levels have been measured using the advanced time delayed βγγ (t) method. The low-lying states in 229 Th and observed transition rates have been interpreted within the quasiparticle–phonon model with inclusion of Coriolis coupling. Two octupole correlated parity partner bands, with K π =5/2 ± and K π =3/2 ± , were identified in 229 Th.
On-line laser spectroscopy of refractory radioisotopes at the JYFL IGISOL facility
1998
A major objective of the laser-IGISOL program has been realized with the first ever on-line observation of collinear laser induced fluorescence from an ion of a refractory element. The measurements demonstrate that the IGISOL can be operated in a mode that produces ion beams of good emittance with reasonable extraction efficiency. The technique has been used to study the neutron-deficient Hf isotopes.
First collinear laser spectroscopy measurements of radioisotopes from an IGISOL ion source
1997
Abstract The standard Doppler-free technique of collinear laser spectroscopy has been successfully applied to radioisotopes from the ion-guide isotope separator (IGISOL) at the University of Jyvaskyla. The laser resonance fluorescence signals for the 140,142,144 Ba radioisotopes show that the ion beam energy spread is less than 6 eV, allowing the laser technique to have both high resolution and a sensitivity comparable with the best obtained at conventional facilities.
First measurement of radioisotopes by collinear laser spectroscopy at an ion-guide separator
1997
The first successful application of an ion-guide separator (IGISOL) for collinear laser spectroscopy of radioisotopes has achieved an efficiency comparable with the best obtained with catcher-ionizer facilities. The ion beam energy spread was determined to be less than 6 eV, allowing laser fluorescence resonance signals for the Ba-140,Ba-142,Ba-144 radioisotopes to be detected with high resolution and sensitivity. Applications of this technique to measuring nuclear properties of refractory elements and short lived isomers promises to be particularly advantageous.
Quadrupole deformed and octupole collective bands in 228Ra
1998
Spins and parities for collective states in $^{228}$Ra have been determined from conversion electron measurements with a mini-orange $\beta$-spectrometer. The fast-timing $\beta\gamma\gamma(t)$ method has been used to measure lifetimes of T$_{1/2}$=550(20) ps and 181(3) ps for the $2^{+}_{1}$ and $4^{+}_{1}$ members of the K=0$^{+}$ band, and T$_{1/2} \leqslant$ 7 ps and $\leqslant$ 6 ps for the $1^{-}_{1}$ and $3^{-}_1$ members of the K = $0^{-}$ band, respectively The quadrupole moments, $Q_{0}$ deduced from the B (E2; 2$_{1}^{+} \rightarrow 0_{1}^{+}$) and B (E2; 4$_{1}^{+} \rightarrow 2_1^{+}$) rates are in good agreement with the previously measured value and the systematics of the reg…
A thirty second isomer in Hf
1997
An isomer has been detected in Hf-171 with a half-life of T-1/2 = 29.5(9) s. The state was populated in the Yb-170(alpha,3n)Hf-171m reaction at a beam energy of E-alpha = 50 MeV in an on-line ion guide isotope separator. The isomeric Hf-17lm(+) beam was extracted from the ion guide, mass-analysed and implanted in the surface of a microchannel-plate. The half-life of the collected activity was measured from the decay of the microchannel-plate count rate. We associate the isomer with the first excited slate in Hf-171 with spin 1/2(-) at an excitation energy of 22(2) keV.
Quadrupole moments and mean-square charge radii in the bismuth isotope chain
1997
Abstract Isotope shifts and hyperfine structures of the 205,206,208,210,210m,212,213 Bi isotopes have been studied on the 306.7 nm line using gas cell laser spectroscopy. The neutron-rich isotopes are the first isotones of Pb to be measured immediately above the N = 126 shell closure. The ground state quadrupole moments of the even- N isotopes increase as neutrons are added or removed from the N = 126 shell, but no corresponding increase is observed in the charge radii.
Nuclear moments and charge radii of bismuth isotopes
2000
Isotope shifts and hyperfine structures have been measured on the 306.7 nm line in bismuth isotopes with A = 205-210, 210m, 212 and 213 by gas cell laser spectroscopy. More precise measurements were made for the A = 207-209 isotopes in atomic beam measurements. Nuclear magnetic and quadrupole moments were deduced. A detailed comparison of the nuclear charge radii systematics has been made in the region using a King plot technique.