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Optics Express

Buffer gas cooling of a continuous CO molecular beam

Aman Gangwar, Tommaso Vedovello, Francesco Pio Merafina, Giacomo Insero, Simone Borri, Paolo De Natale, Gabriele Santambrogio, Sagar Sutradhar

Published Jun 4, 2025• 2 citations
Publisher

Abstract

We characterize a continuous buffer gas cooled source using CO molecules. We show results about the source performance considering different parameters, like gas flow rate, nozzle size, and internal cell volume. The beam contains 2.5 × 10 14 molecules/(s sr) at about 160 m/s. Moreover, for two rotational states we observe an unexpected population distribution that we tentatively attribute to a lower temperature inside the cell. Considering the importance of buffer-gas cooling for experiments on ultracold molecules prepared with direct laser cooling, we believe that our work will improve this key first-stage cooling, accelerating the adoption of molecules in the framework of quantum technologies.

DOI
10.1364/oe.560951

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We present a combined experimental and theoretical study of beam formation from a cryogenic buffer gas cell. Atoms and molecules are loaded into the cell by laser ablation of a target, and are cooled and swept out of the cell by a flow of cold helium. We study the thermalization and flow dynamics inside the cell and measure how the speed, temperature, divergence and extraction efficiency of the beam are influenced by the helium flow. We use a finite element model to simulate the flow dynamics and use the predictions of this model to interpret our experimental results.
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