0000000000021607
AUTHOR
Mustafa Rajabali
showing 16 related works from this author
The Collinear Resonance Ionization Spectroscopy (CRIS) experimental setup at CERN-ISOLDE
2012
The CRIS setup at CERN-ISOLDE is a laser spectroscopy experiment dedicated to the high-resolution study of the spin, hyperfine structure and isotope shift of radioactive nuclei with low production rates (a few per second). It combines the Doppler-free resolution of the in-flight collinear geometry with the high detection efficiency of resonant ionisation. A recent commissioning campaign has demonstrated a 1% experimental efficiency, and as low as a 0.001% non-resonant ionisation. The current status of the experiment and its recent achievements with beams of francium isotopes are reported. The first identified systematic effects are discussed. publisher: Elsevier articletitle: The Collinear …
Nuclear mean-square charge radii of63,64,66,68−82Ga nuclei: No anomalous behavior atN=32
2012
Collinear laser spectroscopy was performed on the ${}^{63,64,66,68\ensuremath{-}82}$Ga isotopes with neutron numbers from $N=32$ to $N=51$. These measurements were carried out at the ISOLDE radioactive ion beam facility at CERN. Here we present the nuclear mean-square charge radii extracted from the isotope shifts and, for the lighter isotopes, new spin and moment values. New ground-state nuclear spin and moments were extracted from the hyperfine spectra of ${}^{63,70}$Ga, measured on an atomic transition in the neutral atom. The ground-state spin of ${}^{63}$Ga is determined to be $I=3/2$. Analysis of the trend in the change in mean-square charge radii of the gallium isotopes demonstrates …
A dedicated decay-spectroscopy station for the collinear resonance ionization experiment at ISOLDE
2013
A newdecay-spectroscopystation(DSS)has been developed to be coupled to the collinear resonance ionization spectroscopy (CRIS) beam line at CERN-ISOLDE. The system uses a rotatable wheel with ten 20 mg=cm2 carbon foils as beam implantation sites for the efficient measurement of charged decay products. Silicon detectors are placed on either side of the carbon foil in an optimal geometry to cover a large solid angle for detecting these charged particles. In addition to the silicon detectors at the on-beam axis position, a second pair of off-beam axis detectors are placed at the wheel position 108 deg. away, allowing longer-lived species to be studied. Up to three high purity germanium detector…
Spins and Magnetic Moments ofK49andK51: Establishing the1/2+and3/2+Level Ordering BeyondN=28
2013
The ground-state spins and magnetic moments of $^{49,51}\mathrm{K}$ have been measured using bunched-beam high-resolution collinear laser spectroscopy at ISOLDE CERN. For $^{49}\mathrm{K}$ a ground-state spin $I=1/2$ was firmly established. The observed hyperfine structure of $^{51}\mathrm{K}$ requires a spin $Ig1/2$ and strongly suggests $I=3/2$. From its magnetic moment $\ensuremath{\mu}(^{51}\mathrm{K})=+0.5129(22){\ensuremath{\mu}}_{N}$ a spin-parity ${I}^{\ensuremath{\pi}}=3/{2}^{+}$ with a dominant $\ensuremath{\pi}1{d}_{3/2}^{\ensuremath{-}1}$ hole configuration was deduced. This establishes for the first time the reinversion of the single-particle levels and illustrates the prominen…
Measurement of the first ionization potential of astatine by laser ionization spectroscopy
2013
The radioactive element astatine exists only in trace amounts in nature. Its properties can therefore only be explored by study of the minute quantities of artificially produced isotopes or by performing theoretical calculations. One of the most important properties influencing the chemical behaviour is the energy required to remove one electron from the valence shell, referred to as the ionization potential. Here we use laser spectroscopy to probe the optical spectrum of astatine near the ionization threshold. The observed series of Rydberg states enabled the first determination of the ionization potential of the astatine atom, 9.31751(8) eV. New ab initio calculations are performed to sup…
Simple Nuclear Structure inCd111–129from Atomic Isomer Shifts
2016
Isomer shifts have been determined in ^{111-129}Cd by high-resolution laser spectroscopy at CERN-ISOLDE. The corresponding mean square charge-radii changes, from the 1/2^{+} and the 3/2^{+} ground states to the 11/2^{-} isomers, have been found to follow a distinct parabolic dependence as a function of the atomic mass number. Since the isomers have been previously associated with simplicity due to the linear mass dependence of their quadrupole moments, the regularity of the isomer shifts suggests a higher order of symmetry affecting the ground states in addition. A comprehensive description assuming nuclear deformation is found to accurately reproduce the radii differences in conjunction wi…
Ground-state spins and moments of72,74,76,78Ga nuclei
2011
Laser spectroscopy was performed on the ${}^{72,74,76,78}$Ga isotopes at On-Line Isotope Mass Separator (ISOLDE) facility, CERN. Ground-state nuclear spins and moments were extracted from the measured hyperfine spectra. The results are compared to shell-model calculations, which provide a detailed probe of the nuclear wave function. The spin is established from the shape of the hyperfine structure and the parity inferred from a comparison of shell-model calculations with the measured nuclear moments. The ground states of ${}^{76,78}$Ga are both assigned a spin and parity of ${I}^{\ensuremath{\pi}}={2}^{\ensuremath{-}}$, while ${}^{74}$Ga is tentatively assigned as ${I}^{\ensuremath{\pi}}={3…
New subshell closure atN=58emerging in neutron-rich nuclei beyondNi78
2010
The structure of neutron-rich nuclei beyond $^{78}\mathrm{Ni}$ was studied using postaccelerated radioactive beams of $^{83,84,85}\mathrm{Ga}$ utilizing $\ensuremath{\beta} \ensuremath{\gamma}$ and $\ensuremath{\beta}\ensuremath{-}n \ensuremath{\gamma}$ spectroscopy. Our data, when combined with energy level systematics, suggests a possible new spherical subshell closure at $N=58$ is created by the nearly degenerated $\ensuremath{\nu}3{s}_{1/2}$ and $\ensuremath{\nu}2{d}_{5/2}$ orbitals being well separated from other orbitals above $N=50$. The near degeneracy of these states could be evidenced by isomerism in this region. The energies of the ${2}_{1}^{+}$ and proposed ${4}_{1}^{+}$ states …
From Calcium to Cadmium: Testing the Pairing Functional through Charge Radii Measurements of Cd100−130
2018
Differences in mean-square nuclear charge radii of $^{100--130}\mathrm{Cd}$ are extracted from high-resolution collinear laser spectroscopy of the $5s\text{ }{^{2}S}_{1/2}\ensuremath{\rightarrow}5p\text{ }{^{2}P}_{3/2}$ transition of the ion and from the $5s5p\text{ }{^{3}P}_{2}\ensuremath{\rightarrow}5s6s\text{ }{^{3}S}_{1}$ transition in atomic Cd. The radii show a smooth parabolic behavior on top of a linear trend and a regular odd-even staggering across the almost complete $sdgh$ shell. They serve as a first test for a recently established new Fayans functional and show a remarkably good agreement in the trend as well as in the total nuclear charge radius.
Magnetic and quadrupole moments of neutron deficient 58-62Cu isotopes
2011
Abstract This paper reports on the ground state nuclear moments measured in 58–62Cu using collinear laser spectroscopy at the ISOLDE facility. The quadrupole moments for 58–60Cu have been measured for the first time as Q ( Cu 58 ) = − 15 ( 3 ) efm 2 , Q ( Cu 59 ) = − 19.3 ( 19 ) efm 2 , Q ( Cu 60 ) = + 11.6 ( 12 ) efm 2 and with higher precision for 61,62Cu as Q ( Cu 61 ) = − 21.1 ( 10 ) efm 2 , Q ( Cu 62 ) = − 2.2 ( 4 ) efm 2 . The magnetic moments of 58,59Cu are measured with a higher precision as μ ( Cu 58 ) = + 0.570 ( 2 ) μ N and μ ( Cu 59 ) = + 1.8910 ( 9 ) μ N . The experimental nuclear moments are compared to large-scale shell-model calculations with the GXPF1 and GXPF1A effective i…
Nuclear charge radii of potassium isotopes beyond N=28
2014
We report on the measurement of optical isotope shifts for 38, 39, 42, 44, 46–51 K relative to 47 K from which changes in the nuclear mean square charge radii across the N = 28 shell closure are deduced. The investigation was carried out by bunched-beam collinear laser spectroscopy at the CERN-ISOLDE radioactive ion-beam facility. Mean square charge radii are now known from 37K to 51K, covering all ν f7/2-shell as well as all νp3/2-shell nuclei. These measurements, in conjunction with those of Ca, Cr, Mn and Fe, provide a first insight into the Z dependence of the evolution of nuclear size above the shell closure at N = 28
Development of the CRIS (Collinear Resonant Ionisation Spectroscopy) beam line
2012
The CRIS (Collinear Resonant Ionisation Spectroscopy) beam line is a new experimental set up at the ISOLDE facility at CERN. CRIS is being constructed for highresolution laser spectroscopy measurements on radioactive isotopes. These measurements can be used to extract nuclear properties of isotopes far from stability. The CRIS beam line has been under construction since 2009 and testing of its constituent parts have been performed using stable and radioactive ion beams, in preparation for its first on-line run. This paper will present the current status of the CRIS experiment and highlight results from the recent tests. ispartof: pages:012070-6 ispartof: Journal of Physics: Conference Serie…
Proton-Neutron Pairing Correlations in the Self-Conjugate NucleusK38Probed via a Direct Measurement of the Isomer Shift
2014
A marked difference in the nuclear charge radius was observed between the ${I}^{\ensuremath{\pi}}={3}^{+}$ ground state and the ${I}^{\ensuremath{\pi}}={0}^{+}$ isomer of $^{38}\mathrm{K}$ and is qualitatively explained using an intuitive picture of proton-neutron pairing. In a high-precision measurement of the isomer shift using bunched-beam collinear laser spectroscopy at CERN-ISOLDE, a change in the mean-square charge radius of $⟨{r}_{\mathrm{c}}^{2}⟩{(}^{38}{\mathrm{K}}^{m})\ensuremath{-}⟨{r}_{\mathrm{c}}^{2}⟩{(}^{38}{\mathrm{K}}^{g})=0.100(6)\text{ }\text{ }{\mathrm{fm}}^{2}$ was obtained. This is an order of magnitude more accurate than the result of a previous indirect measurement fr…
Laser assisted decay spectroscopy at the CRIS beam line at ISOLDE
2012
A new collinear resonant ionization spectroscopy (Cris)beam line has recently been installed at Isolde, Cern utilising lasers to combine collinear laser spectroscopy and resonant ionization spectroscopy. The combined technique offers the ability to purify an ion beam that is heavily contaminated with radioactive isobars, including the ground state of an isotope from its isomer, allowing sensitive secondary experiments to be performed. A new programme aiming to use the Cris technique for the separation of nuclear isomeric states for decay spectroscopy will commence in 2011. A decay spectroscopy station, consisting of a rotating wheel implantation system for alpha decay spectroscopy, and thre…
Shell structure of potassium isotopes deduced from their magnetic moments
2014
\item[Background] Ground-state spins and magnetic moments are sensitive to the nuclear wave function, thus they are powerful probes to study the nuclear structure of isotopes far from stability. \item[Purpose] Extend our knowledge about the evolution of the $1/2^+$ and $3/2^+$ states for K isotopes beyond the $N = 28$ shell gap. \item[Method] High-resolution collinear laser spectroscopy on bunched atomic beams. \item[Results] From measured hyperfine structure spectra of K isotopes, nuclear spins and magnetic moments of the ground states were obtained for isotopes from $N = 19$ up to $N = 32$. In order to draw conclusions about the composition of the wave functions and the occupation of the …
Laser spectroscopy of gallium isotopes beyond N = 50
2012
The installation of an ion-beam cooler-buncher at the ISOLDE, CERN facility has provided increased sensitivity for collinear laser spectroscopy experiments. A migration of single-particle states in gallium and in copper isotopes has been investigated through extensive measurements of ground state and isomeric state hyperfine structures. Lying beyond the N = 50 shell closure, 82Ga is the most exotic nucleus in the region to have been studied by optical methods, and is reported here for the first time. ispartof: pages:012071-6 ispartof: Journal of Physics: Conference Series vol:381 issue:1 pages:012071-6 ispartof: Rutherford Centennial Conference on Nuclear Physics location:Manchester, UK dat…