Comparison of two multiplexed portable cold-atom vacuum standards

We compare the vacuum measured by two portable cold-atom vacuum standards (pCAVSs) based on ultracold 7Li atoms. pCAVSs are quantum-based standards that use a priori scattering calculations to convert a measured loss rate of cold atoms from a conservative trap into a background gas pressure. Our pCAVS devices share the same laser system and measure the vacuum concurrently. The two pCAVSs together detected a leak with a rate on the order of [Formula: see text] Pa l/s. After fixing the leak, the pCAVS measured pressure of about 40 nPa with 2.6% uncertainty. The two pCAVSs agree within their uncertainties, even when swapping some of their component parts. Operation of the pCAVS was found to cause some additional outgassing, on the order of [Formula: see text] Pa l/s, which can be mitigated in the future by better thermal management.