Continuous loading of an electrostatic trap for polar molecules

A continuously operated electrostatic trap for polar molecules is demonstrated. The trap has a volume of $\ensuremath{\approx}0.6\text{ }\text{ }{\mathrm{cm}}^{3}$ and holds molecules with a positive Stark shift. With deuterated ammonia from a quadrupole velocity filter, a trap density of $\ensuremath{\approx}{10}^{8}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$ is achieved with an average lifetime of 130 ms and a motional temperature of $\ensuremath{\approx}300\text{ }\text{ }\mathrm{mK}$. The trap offers good starting conditions for high-precision measurements, and can be used as a first stage in cooling schemes for molecules and as a ``reaction vessel'' in cold chemistry.