20 research outputs found
A novel transparent charged particle detector for the CPET upgrade at TITAN
The detection of an electron bunch exiting a strong magnetic field can prove
challenging due to the small mass of the electron. If placed too far from a
solenoid's entrance, a detector outside the magnetic field will be too small to
reliably intersect with the exiting electron beam because the light electrons
will follow the diverging magnetic field outside the solenoid. The TITAN group
at TRIUMF in Vancouver, Canada, has made use of advances in the practice and
precision of photochemical machining (PCM) to create a new kind of charge
collecting detector called the "mesh detector." The TITAN mesh detector was
used to solve the problem of trapped electron detection in the new Cooler
PEnning Trap (CPET) currently under development at TITAN. This thin array of
wires etched out of a copper plate is a novel, low profile, charge agnostic
detector that can be made effectively transparent or opaque at the user's
discretion.Comment: 6 Pages. 6 Figures. Submitted to Nuclear Instruments and Methods in
Physics Research Section A: Accelerators, Spectrometers, Detectors and
Associated Equipmen
Mass Measurements of Neutron-Rich Gallium Isotopes Refine Production of Nuclei of the First r-Process Abundance Peak in Neutron Star Merger Calculations
We report mass measurements of neutron-rich Ga isotopes Ga with
TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). The measurements
determine the masses of Ga in good agreement with previous
measurements. The masses of Ga and Ga were measured for the first
time. Uncertainties between keV were reached. The new mass values
reduce the nuclear uncertainties associated with the production of A
84 isotopes by the \emph{r}-process for astrophysical conditions that might be
consistent with a binary neutron star (BNS) merger producing a blue kilonova.
Our nucleosynthesis simulations confirm that BNS merger may contribute to the
first abundance peak under moderate neutron-rich conditions with electron
fractions
High-precision QEC-value measurement of the superallowed β+ emitter 22Mg and an ab initio evaluation of the A = 22 isobaric triplet
A direct -value measurement of the superallowed emitter
Mg was performed using TRIUMF's Ion Trap for Atomic and Nuclear science
(TITAN). The direct ground-state to ground-state atomic mass difference between
Mg and Na was determined to be ~keV,
representing the most precise single measurement of this quantity to date. In a
continued push towards calculating superallowed isospin-symmetry-breaking (ISB)
corrections from first principles, ab-initio shell-model calculations of the
IMME are also presented for the first time using the valence-space
in-medium similarity renormalization group formalism. With particular starting
two- and three-nucleon forces, this approach demonstrates a level of agreement
with the experimental data that suggests reliable ab-initio calculations of
superallowed ISB corrections are now possible
Precision mass measurements of 125–127Cd isotopes and isomers approaching the N = 82 closed shell
We present the results of precision mass measurements of neutron-rich cadmium
isotopes. These nuclei approach the closed neutron shell and are
important to nuclear structure as they lie near doubly-magic Sn on the
chart of nuclides. Of particular note is the clear identification of the ground
state mass in Cd along with the isomeric state. We show that the ground
state identified in a previous mass measurement which dominates the mass value
in the Atomic Mass Evaluation is an isomeric state. In addition to
Cd, we present other cadmium masses measured (Cd and
Cd) in a recent TITAN experiment at TRIUMF. Finally, we compare our
measurements to new \emph{ab initio} shell-model calculations and comment on
the state of the field in the region.Comment: 8 Pages with citations, 3 Figures, 2 Table
Quenching of the N=32 neutron shell closure studied via precision mass measurements of neutron-rich vanadium isotopes
We performed the first direct mass measurements of neutron-rich vanadium 52–55V isotopes passing the N=32 neutron shell closure with TRIUMF's Ion Trap for Atomic and Nuclear science. The new direct measurements confirm all previous indirect results. Through a reduced uncertainty of the mass of 55V we confirm the quenching of the N=32 neutron shell closure in vanadium. We discuss the evolution of the N=32 neutron shell closure between K and Cr and show similar signatures in the half-life surface when studied along the isotopic chains
Dawning of the N=32 shell closure seen through precision mass measurements of neutron-rich titanium isotopes
A precision mass investigation of the neutron-rich titanium isotopes
Ti was performed at TRIUMF's Ion Trap for Atomic and Nuclear science
(TITAN). The range of the measurements covers the shell closure and the
overall uncertainties of the Ti mass values were significantly
reduced. Our results confirm the existence of a weak shell effect at ,
establishing the abrupt onset of this shell closure. Our data were compared
with state-of-the-art \textit{ab-initio} shell model calculations which,
despite very successfully describing where the shell gap is strong,
overpredict its strength and extent in titanium and heavier isotones. These
measurements also represent the first scientific results of TITAN using the
newly commissioned Multiple-Reflection Time-of-Flight Mass Spectrometer
(MR-TOF-MS), substantiated by independent measurements from TITAN's Penning
trap mass spectrometer
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Reinvestigation of the Direct Two-proton Decay of the Long-lived Isomer 94Agm [0.4 s, 6.7 MeV, (21+)]
An attempt to confirm the reported direct one-proton and two-proton decays of the (21+) isomer at 6.7(5) MeV in 94Ag has been made. The 0.39(4) s half-life of the isomer permitted use of a helium-jet system to transport reaction products from the 40Ca + natNi reaction at 197 MeV to a low-background area; 24 gas Delta E-(Si) E detector telescopes were used to identify emitted protons down to 0.4 MeV. No evidence was obtained for two-proton radioactivity with a summed energy of 1.9(1) MeV and a branching ratio of 0.5(3)percent. Two groups of one-proton radioactivity from this isomer had also been reported; our data confirm the lower energy group at 0.79(3) MeV with its branching ratio of 1.9(5)percent