Investigation of cold collision in a two isotope magneto-optical trap for Krypton atoms

We report simultaneous cooling and trapping of metastable 84Kr (84Kr*) and metastable 86Kr (86Kr*) atoms by overlapping the cooling laser beams for these different isotopes in the same region of a magneto-optical trap (MOT). Approximately 2 × 105 atoms of each isotope were trapped in this two isotope-MOT (TIMOT). We have investigated the heteronuclear collision trap loss rates for each isotope due to the presence of cold atoms of other isotope using the TIMOT loading curves. The two body heteronuclear loss rate coefficient ${\beta }_{{}^{84}Kr*-{}^{86}Kr*}$ (i.e. for the loss of 84Kr* due to presence of 86Kr*) and the reciprocal loss rate coefficient ${\beta }_{{}^{86}Kr*-{}^{84}Kr*}$ (i.e. for the loss of 86Kr* due to presence of 84Kr*) are measured to be (8.7 ± 0.8) × 10−10 cm3 s−1 and (8.8 ± 0.8) × 10−10 cm3 s−1 respectively for laser beam intensity values of 21 mW cm−2 (for cooling of 84Kr*) and 64 mW cm−2 (for cooling of 86Kr*). The dependence of heteronuclear cold collision loss rate on cooling laser beams intensity has also been studied and compared with homonuclear cold collision loss rate.