Buffer-gas cooling of molecules in the low-density regime: Comparison between simulation and experiment

Abstract

Cryogenic buffer gas cells have been a workhorse for the cooling of molecules in the last decades. The straightforward sympathetic cooling principle makes them applicable to a huge variety of different species. Notwithstanding this success, detailed simulations of buffer gas cells are rare, and have never been compared to experimental data in the regime of low to intermediate buffer gas densities. Here, we present a numerical approach based on a trajectory analysis, with molecules performing a random walk in the cell due to collisions with a homogeneous buffer gas. This method can reproduce experimental flux and velocity distributions of molecules emerging from the buffer gas cell for varying buffer gas densities. This includes the strong decrease in molecule output from the cell for increasing buffer gas density and the so-called boosting effect, when molecules are accelerated by buffer-gas atoms after leaving the cell. The simulations provide various insights which could substantially improve buffer-gas cell design.

References in corpus (13)

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Cited by in corpus (8)

• Cryogenic Buffer Gas beams of AlF, CaF, MgF, YbF, Al, Ca, Yb and NO -- a comparison
• Bright, continuous beams of cold free radicals
• Electrostatic focusing of cold and heavy molecules for the ACME electron EDM search
• Simulation of Cryogenic Buffer Gas Beams
• The chemistry of AlF and CaF production in buffer gas sources
• Dynamics of a buffer-gas-loaded, deep optical trap for molecules
• Measurement of Doppler effects in cryogenic buffer-gas cell
• Photon spin molasses for laser cooling molecular rotation