Aaron Gallant

Bio: Aaron Gallant is an academic researcher from Lawrence Livermore National Laboratory. The author has contributed to research in topics: Penning trap & Ion trap. The author has an hindex of 19, co-authored 66 publications receiving 1180 citations. Previous affiliations of Aaron Gallant include TRIUMF & University of British Columbia.

Measurement of the two-halo neutron transfer reaction (1)H((11)Li, (9)Li)(3)H at 3A MeV.

Abstract: The p({sup 11}Li,{sup 9}Li)t reaction has been studied for the first time at an incident energy of 3A MeV at the new ISAC-2 facility at TRIUMF. An active target detector MAYA, built at GANIL, was used for the measurement. The differential cross sections have been determined for transitions to the {sup 9}Li ground and first excited states in a wide range of scattering angles. Multistep transfer calculations using different {sup 11}Li model wave functions show that wave functions with strong correlations between the halo neutrons are the most successful in reproducing the observation.

First use of high charge states for mass measurements of short-lived nuclides in a Penning trap.

Abstract: Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using the TITAN facility at TRIUMF. Compared to singly charged ions, this provides an improvement in experimental precision that scales with the charge state $q$. Neutron-deficient Rb isotopes have been charge bred in an electron beam ion trap to $q=8\ensuremath{-}12+$ prior to injection into the Penning trap. In combination with the Ramsey excitation scheme, this unique setup creating low energy, highly charged ions at a radioactive beam facility opens the door to unrivaled precision with gains of 1--2 orders of magnitude. The method is particularly suited for short-lived nuclides such as the superallowed $\ensuremath{\beta}$ emitter $^{74}\mathrm{Rb}$ (${T}_{1/2}=65\text{ }\text{ }\mathrm{ms}$). The determination of its atomic mass and an improved ${Q}_{EC}$ value are presented.

The on-line charge breeding program at TRIUMF's Ion Trap For Atomic and Nuclear Science for precision mass measurements.

Abstract: TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN) constitutes the only high precision mass measurement setup coupled to a rare isotope facility capable of increasing the charge state of short-lived nuclides prior to the actual mass determination in a Penning trap. Recent developments around TITAN's charge breeder, the electron beam ion trap, form the basis for several successful experiments on radioactive isotopes with half-lives as low as 65 ms and in charge states as high as 22+.

New Precision Mass Measurements of Neutron-Rich Calcium and Potassium Isotopes and Three-Nucleon Forces

Abstract: We present precision Penning trap mass measurements of neutron-rich calcium and potassium isotopes in the vicinity of neutron number N=32. Using the TITAN system, the mass of 51K was measured for the first time, and the precision of the (51,52)Ca mass values were improved significantly. The new mass values show a dramatic increase of the binding energy compared to those reported in the atomic mass evaluation. In particular, 52Ca is more bound by 1.74 MeV, and the behavior with neutron number deviates substantially from the tabulated values. An increased binding was predicted recently based on calculations that include three-nucleon (3N) forces. We present a comparison to improved calculations, which agree remarkably with the evolution of masses with neutron number, making neutron-rich calcium isotopes an exciting region to probe 3N forces.

TITAN's Digital RFQ Ion Beam Cooler and Buncher, Operation and Performance

Abstract: We present a description of the Radio Frequency Quadrupole (RFQ) ion trap built as part of the TITAN facility. It consists of a gas-filled, segmented, linear Paul trap and is the first stage of the TITAN setup with the purpose of cooling and bunching radioactive ion beams delivered from ISAC-TRIUMF. This is the first such device to be driven digitally, i.e., using a high voltage ( V pp = 400 V ), wide bandwidth ( 0.2 f 1.2 MHz ) square-wave as compared to the typical sinusoidal wave form. Results from the commissioning of the device as well as systematic studies with stable and radioactive ions are presented including efficiency measurements with stable 133Cs and radioactive 124,126Cs. A novel and unique mode of operation of this device is also demonstrated where the cooled ion bunches are extracted in reverse mode, i.e., in the same direction as previously injected.

Nuclear Instruments and Methods

Abstract: The presence of a sample in the neutron field of a nuclear reactor creates a perturbation of the local neutron fluxes. In general, the interpretation of the sample activation due to thermal and epithermal neutrons requires the knowledge of two corrective parameters: the thermal neutron self-shielding factor, Gth, and the resonance neutron self-shielding factor, Gres. Thermal neutron self-shielding factors in different materials (Al, Au, Cd, Co, Cu, Eu, Gd, In, Ir, Mo, Ni, Pt, Pb, Rh, Sc, Sm and Ta) and different geometries (foils, wires, spheres and) have been calculated by using the MCNP code.