Engineering topics

Chaudhuri, A.

Publications and source records attributed to Chaudhuri, A..

3 records

DOE OSTI2017

Precision mass measurements of magnesium isotopes and implications for the validity of the isobaric mass multiplet equation

If the mass excess of neutron-deficient nuclei and their neutron-rich mirror partners are both known, it can be shown that deviations of the isobaric mass multiplet equation (IMME) in the form of a cubic term can be probed. Such a cubic term was probed by using the atomic mass of neutron-rich magnesium isotopes measured using the TITAN Penning trap and the recently measured proton-separation energies of 29 Cl and 30 Ar. The atomic mass of 27 Mg was found to be within 1.6σ of the value stated in the Atomic Mass Evaluation. The atomic masses of 28,29 Mg were measured to be both within 1σ, while being 7 and 33 times more precise, respectively. Using the 29 Mg mass excess and previous measurements of 29 Cl, we uncovered a cubic coefficient of d = 28(7)keV, which is the largest known cubic coefficient of the IMME. This departure, however, could also be caused by experimental data with unknown systematic errors. Hence there is a need to confirm the mass excess of 28 S and the one-neutron separation energy of 29 Cl, which have both come from a single measurement. Lastly, our results were compared with ab initio calculations from the valence-space in-medium similarity renormalization group, resulting in a good agreement.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2015

Limit on Tensor Currents from Li 8 β Decay

In the standard model, the weak interaction is formulated with a purely vector-axial-vector ($V\text{-}A$) structure. Without restriction on the chirality of the neutrino, the most general limits on tensor currents from nuclear ${\beta}$ decay are dominated by a single measurement of the ${\beta}\text{-}\overline{{\nu}}$ correlation in $^{6}\mathrm{He}$ ${\beta}$ decay dating back over a half century. In the present paper, the ${\beta}\text{-}\overline{{\nu}}\text{-}{\alpha}$ correlation in the ${\beta}$ decay of $^{8}\mathrm{Li}$ and subsequent ${\alpha}$-particle breakup of the ${^{8}\mathrm{Be}}^{*}$ daughter was measured. The results are consistent with a purely $V\text{-}A$ interaction and in the case of couplings to right-handed neutrinos (${C}_{T}={-}{C}_{T}^{{'}}$) limits the tensor fraction to $|{C}_{T}/{C}_{A}{|}^{2}<0.011$ (95.5% C.L.). Finally, the measurement confirms the $^{6}\mathrm{He}$ result using a different nuclear system and employing modern ion-trapping techniques subject to different systematic uncertainties.

74 ATOMIC AND MOLECULAR PHYSICS↗

DOE OSTI2015

Progress at the TITAN-EBIT

Precision mass measurements of short-lived isotopes provide insight into a wide array of physics, including nuclear structure, nucleosynthesis, and tests of the Standard Model. The precision of Penning trap mass spectrometry (PTMS) measurements is limited by the lifetime of the isotopes of interest, but scales proportionally with their charge state q, making highly charged ions attractive for mass measurements of nuclides far from stability. TITAN, TRIUMF's Ion Trap(s) for Atomic and Nuclear science, is currently the only setup in the world coupling an EBIT to a rare isotope facility for the purpose of PTMS. Charge breeding ions for Penning trap mass spectrometry, however, entails specific set of challenges. To make use of its potential, efficiencies have to be high, breeding times have to be short and the ion energy spread has to be small. An overview of the TITAN facility and charge-breeding program is given, current and future developments are highlighted and some selected results are presented.

74 ATOMIC AND MOLECULAR PHYSICS↗