Measurement of $\bf{Sr-N_{2}}$ elastic collision cross section in Magneto-Optical Trap

We experimentally measured the collision cross section between $^{88}$Sr$-$N$_{2}$ and Sr$-$Sr in a Magneto Optical Trap (MOT). These collision cross sections are estimated by measuring the atomic loss rate as a function of background pressure of N$_{2}$ gas. The measurements performed here are important as N$_{2}$ is one of the prominent gases that remains in the vacuum chamber even after bake-out, directly affecting the trap lifetime. The knowledge of this cross section is imperative in order to quantify the contribution of background gas collisions in the total error budget of Strontium based optical atomic clock. We also estimate the loss rate caused by the combined effect of the decay of atoms in the long-lived ${^3P}_0$ state and temperature induced atomic losses from the capture volume of the MOT. The later occurs due to a significant amount of time spent by the atoms in the states which are insensitive to the first stage cooling light. We find that the contribution of this channel is dominant in comparison to the other atomic loss channels. This experiment highlights the importance of including the temperature dependant loss channel in studies which rely on the measurement of total loss rate.