66 research outputs found
High-precision mass measurements of nickel, copper, and gallium isotopes and the purported shell closure at N=40
High-precision mass measurements of more than thirty neutron-rich nuclides
around the Z=28 closed proton shell were performed with the triple-trap mass
spectrometer ISOLTRAP at ISOLDE/CERN to address the question of a possible
neutron shell closure at N=40. The results, for 57,60,64-69Ni (Z=28),
65-74,76Cu (Z=29), and 63-65,68-78Ga (Z=31), have a relative uncertainty of the
order of 10^8. In particular, the masses of 72-74,76Cu have been measured for
the first time. We analyse the resulting mass surface for signs of magicity,
comparing the behavior of N=40 to that of known magic numbers and to mid-shell
behavior. Contrary to nuclear spectroscopy studies, no indications of a shell
or sub-shell closure are found for N=40.Comment: 14 figure
Evidence for a breakdown of the Isobaric Multiplet Mass Equation: A study of the A=35, T=3/2 isospin quartet
Mass measurements on radionuclides along the potassium isotope chain have
been performed with the ISOLTRAP Penning trap mass spectrometer. For 35K
T1/2=178ms) to 46K (T1/2=105s) relative mass uncertainties of 2x10-8 and better
have been achieved. The accurate mass determination of 35K (dm=0.54keV) has
been exploited to test the Isobaric Multiplet Mass Equation (IMME) for the
A=35, T=3/2 isospinquartet. The experimental results indicate a deviation from
the generally adopted quadratic form.Comment: 8 pages, 4 figure
Transport and cooling of singly-charged noble gas ion beams
The transport and cooling of noble gas singly-charged ion beams by means of a
Radio Frequency Quadrupole Cooler Buncher (RFQCB) have been studied at the
LIMBE low energy beam line of the GANIL facility. Ions as light as
have been cooled and stored before their extraction in bunches using as
buffer gas. Bunches characteristics have been studied as a function of the
parameters of the device. Sizeable transmissions of up to 10 have been
obtained. A detailed study of the lifetime of ions inside the buncher has been
performed giving an estimate of the charge exchange cross-section. Results of a
microscopic Monte-Carlo transport code show reasonable agreement with
experimental data.Comment: 13 figure
High-precision masses of neutron-deficient rubidium isotopes using a Penning trap mass spectrometer
The atomic masses of the neutron-deficient radioactive rubidium isotopes Rb have been measured with the Penning trap mass spectrometer ISOLTRAP. Using the time-of-flight cyclotron resonance technique, relative mass uncertainties ranging from to were achieved. In all cases, the mass precision was significantly improved as compared with the prior Atomic-Mass Evaluation; no significant deviations from the literature values were observed. The exotic nuclide Rb with a half-life of only 65 ms, is the shortest-lived nuclide on which a high-precision mass measurement in a Penning trap has been carried out. The significance of these measurements for a check of the conserved-vector-current hypothesis of the weak interaction and the unitarity of the Cabibbo-Kobayashi-Maskawa matrix is discussed
Mass spectrometry of atomic ions produced by in-trap decay of short-lived nuclides
The triple-trap mass spectrometer ISOLTRAP at ISOLDE/CERN has demonstrated the feasibility of mass spectrometry of in-trap-decay product ions. This novel technique gives access to radionuclides, which are not produced directly at ISOL-type radioactive ion beam facilities. As a proof of principle, the in-trap decay of has been investigated in a Penning trap filled with helium buffer gas. The half-life of the mother nuclide was confirmed and the recoiling daughter ion was contained within the trap. The ions of either the mother or the daughter nuclide were transferred to a precision Penning trap, where their mass was determined
Mass measurements beyond the major r-process waiting point 80Zn
High-precision mass measurements on neutron-rich zinc isotopes 71m,72-81Zn
have been performed with the Penning trap mass spectrometer ISOLTRAP. For the
first time the mass of 81Zn has been experimentally determined. This makes 80Zn
the first of the few major waiting points along the path of the astrophysical
rapid neutron capture process where neutron separation energy and neutron
capture Q-value are determined experimentally. As a consequence, the
astrophysical conditions required for this waiting point and its associated
abundance signatures to occur in r-process models can now be mapped precisely.
The measurements also confirm the robustness of the N = 50 shell closure for Z
= 30 farther from stability.Comment: 4 pages, 3 figure
Atomic mass measurements of short-lived nuclides around the doubly-magic 208Pb
Accurate atomic mass measurements of neutron-deficient and neutron-rich
nuclides around the doubly-magic 208Pb and of neutron-rich cesium isotopes were
performed with the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The
masses of 145,147Cs, 181,183Tl, 186Tlm, 187Tl, 196Tlm, 205Tl, 197Pbm, 208Pb,
190 to 197Bi, 209,215,216Bi, 203,205,229Fr, and 214,229,230Ra were determined.
The obtained relative mass uncertainty in the range of to is not only required for safe identification of isomeric states
but also allows mapping the detailed structure of the mass surface. A mass
adjustment procedure was carried out and the results included into the Atomic
Mass Evaluation. The resulting separation energies are discussed and the mass
spectrometric and laser spectroscopic data are examined for possible
correlations.Comment: 40 pages, 20 figures, accept. for publication in Nucl. Phys.
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