We report on the buffer-gas cooling and trapping of CrH and MnH molecules in a magnetic quadrupole trap with densities on the order of ${10}^6{\mathrm{cm}}^{-3}$ at a temperature of $650\mathrm{mK}$. Storage times of up to $180\mathrm{ms}$ have been observed, corresponding to a 20-fold lifetime enhancement with respect to the field-free diffusion through the ${}^3\mathrm{He}$ buffer-gas. Using Monte Carlo trajectory simulations, inelastic molecule-${}^3\mathrm{He}$ collision cross sections of $1.6\times {10}^{-18}$ and $3.1\times {10}^{-17}{\mathrm{cm}}^2$ are extracted for CrH and MnH, respectively. Furthermore, elastic molecule-${}^3\mathrm{He}$ collision cross sections of $1.4(\pm 0.5)\times {10}^{-14}{\mathrm{cm}}^2$ are determined for both species. We conclude that the confinement time of these molecules in a magnetic trapping field is limited by inelastic collisions with the helium atoms leading to Zeeman relaxation.

• Received 20 June 2008

DOI:https://doi.org/10.1103/PhysRevA.78.032707