arXiv subjects

S. V. Nguyen

Publications and source records attributed to S. V. Nguyen.

3 recordsLinked to original sources

arXiv2007

Spin-exchange collisions of submerged shell atoms below 1 Kelvin

Angular momentum changing collisions can be suppressed in atoms whose valence electrons are submerged beneath filled shells of higher principle quantum number. To determine whether spin-exchange collisions are suppressed in these "submerged shell" atoms, we measured spin-exchange collisions of six hyperfine states of Mn at temperatures below 1 K. Although the 3d valence electrons in Mn are submerged beneath a filled 4s orbital, we find that the spin exchange rate coefficients are similar to those of Na and H (which are non-submerged shell atoms).

physics.atom-ph↗

arXiv2005

High-flux beam source for cold, slow atoms or molecules

We demonstrate and characterize a high-flux beam source for cold, slow atoms or molecules. The desired species is vaporized using laser ablation, then cooled by thermalization in a cryogenic cell of buffer gas. The beam is formed by particles exiting a hole in the buffer gas cell. We characterize the properties of the beam (flux, forward velocity, temperature) for both an atom (Na) and a molecule (PbO) under varying buffer gas density, and discuss conditions for optimizing these beam parameters. Our source compares favorably to existing techniques of beam formation, for a variety of applications.

physics.atom-ph↗

arXiv2003

Buffer gas cooling and trapping of atoms with small magnetic moments

Buffer gas cooling was extended to trap atoms with small magnetic moment (mu). For mu greater than or equal to 3mu_B, 1e12 atoms were buffer gas cooled, trapped, and thermally isolated in ultra high vacuum with roughly unit efficiency. For mu < 3mu_B, the fraction of atoms remaining after full thermal isolation was limited by two processes: wind from the rapid removal of the buffer gas and desorbing helium films. In our current apparatus we trap atoms with mu greater than or equal to 1.1mu_B, and thermally isolate atoms with mu greater than or equal to 2mu_B. Extrapolation of our results combined with simulations of the loss processes indicate that it is possible to trap and evaporatively cool mu = 1mu_B atoms using buffer gas cooling.

cond-mat↗