Cryogenic buffer-gas loading and magnetic trapping of CrH and MnH molecules

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 10⁶cm^-3 at a temperature of 650mK . Storage times of up to 180ms have been observed, corresponding to a 20-fold lifetime enhancement with respect to the field-free diffusion through the He3 buffer-gas. Using Monte Carlo trajectory simulations, inelastic molecule- He3 collision cross sections of 1.6×10^-18 and 3.1×10^-17cm² are extracted for CrH and MnH, respectively. Furthermore, elastic molecule- He3 collision cross sections of 1.4(±0.5)×10^-14cm² 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.