Electrostatic extraction of cold molecules from a cryogenic reservoir

Abstract

We present a method which delivers a continuous, high-density beam of slow and internally cold polar molecules. In our source, warm molecules are first cooled by collisions with a cryogenic helium buffer gas. Cold molecules are then extracted by means of an electrostatic quadrupole guide. For ND${}_3$ the source produces fluxes up to $(7{\pm }_4^7)\times 10^{10}$ molecules/s with peak densities up to $(1.0{\pm }_{0.6}^{1.0})\times 10^9$ molecules/cm${}^3$. For H${}_2$CO the population of rovibrational states is monitored by depletion spectroscopy, resulting in single-state populations up to $(82\pm 10)$.

4 pages, 4 figures, changes to the text, updated figures and references