arXiv subjects

Colin B. Connolly

Publications and source records attributed to Colin B. Connolly.

4 recordsLinked to original sources

arXiv2013

Properties of the ground $^3$F$_2$ state and the excited $^3$P$_0$ state of atomic thorium in cold collisions with $^3$He

We measure inelastic collisional cross sections for the ground $^3$F$_2$ state and the excited $^3$P$_0$ state of atomic thorium in cold collisions with $^3$He. We determine for Th ($^3$F$_2$) at 800 mK the ratio $γ\approx 500$ of the momentum-transfer to Zeeman relaxation cross sections for collisions with $^3$He. For Th ($^3$P$_0$), we study electronic inelastic processes and find no quenching even after $10^6$ collisions. We also determine the radiative lifetime of Th ($^3$P$_0$) to be $τ> 130$ ms. This great stability of the metastable state opens up the possibility for further study, including trapping.

physics.atom-ph↗

arXiv2013

Vibrational quenching of the electronic ground state in ThO in cold collisions with $^3$He

We measure the ratio $γ$ of the momentum-transfer to the vibrational quenching cross section for the X ($^1Σ^+$), $ν=1$, $\mathrm{J=0}$ state of molecular thorium monoxide (ThO) in collisions with atomic $^3$He between 800 mK and 2.4 K. We observe indirect evidence for ThO--He van der Waals' complex formation, which has been predicted by theory. We determine the 3-body recombination rate constant $Γ_3$ at 2.4 K, and establish that the binding energy E$_b >$ 4 K.

physics.atom-ph↗

arXiv2009

Permeability of Noble Gases through Kapton, Butyl, Nylon, and "Silver Shield"

Noble gas permeabilities and diffusivities of Kapton, butyl, nylon, and "Silver Shield" are measured at temperatures between 22C and 115C. The breakthrough times and solubilities at 22C are also determined. The relationship of the room temperature permeabilities to the noble gas atomic radii is used to estimate radon permeability for each material studied. For the noble gases tested, Kapton and Silver Shield have the lowest permeabilities and diffusivities, followed by nylon and butyl, respectively.

physics.ins-det↗

arXiv2009

Large spin relaxation rates in trapped submerged-shell atoms

Spin relaxation due to atom-atom collisions is measured for magnetically trapped erbium and thulium atoms at a temperature near 500 mK. The rate constants for Er-Er and Tm-Tm collisions are 3.0 times 10^-10 cm^3 s^-1 and 1.1 times 10^-10 cm^3 s^-1, respectively, 2-3 orders of magnitude larger than those observed for highly magnetic S-state atoms. This is strong evidence for an additional, dominant, spin relaxation mechanism, electrostatic anisotropy, in collisions between these "submerged-shell" L > 0 atoms. These large spin relaxation rates imply that evaporative cooling of these atoms in a magnetic trap will be highly inefficient.

physics.atom-ph↗