Magnetic Trapping of Silver and Copper, and Anomalous Spin Relaxation in the Ag-He System

Nathan Brahms,Cort Johnson,Tom Greytak,Daniel Kleppner,Bonna Newman,John Doyle

doi:10.1103/physrevlett.101.103002

Nathan Brahms, Cort Johnson + Show 4 more

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https://doi.org/10.1103/physrevlett.101.103002

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Abstract

We have trapped large numbers of copper (Cu) and silver (Ag) atoms using buffer-gas cooling. Up to 3 x 10{12} Cu atoms and 4 x 10{13} Ag atoms are trapped. Lifetimes are as long as 5 s, limited by collisions with the buffer gas. Ratios of elastic to inelastic collision rates with He are >or=10{6}, suggesting Cu and Ag are favorable for use in ultracold applications. The temperature dependence of the Ag-3He collision rate varies as T;{5.8+/-0.4}. We find that this temperature dependence is inconsistent with the behavior predicted for relaxation arising from the spin-rotation interaction, and conclude that the Ag-3He system displays anomalous collisional behavior in the multiple-partial wave regime. Gold (Au) was ablated into 3He buffer gas, however, atomic Au lifetimes were observed to be too short to permit trapping.

Highlights

The Harvard community has made this article openly available
Ratios of elastic to inelastic collision rates with He are * 106, suggesting Cu and Ag are favorable for use in ultracold applications
The temperature dependence of the Ag-3He collision rate varies as T5:8Æ0:4

Summary

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Nathan, Bonna Newman, Cort Johnson, Tom Greytak, Daniel Kleppner, and John Doyle. 2008. Using buffer-gas cooling we trap large, dense samples of the noble metals copper (Cu) and silver (Ag) at temperatures as low as 300 mK and with lifetimes as long as 5 s, limited by collisions with the 3He buffer gas. We study these collisions, discovering an anomalous temperature dependence for Ag-3He inelastic collisions. Week ending 5 SEPTEMBER 2008 ture of the buffer-gas TBG within 100 collisions Because this temperature is lower than the energy of interaction Etrap between the atoms and the magnetic field at the cell wall, atoms that are in a low-field seeking Zeeman state are trapped. For atoms in the lowest-order diffusion mode, the 1=e lifetime of atoms in a cell of length L and radius R is [8]

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Cu spectrum