%0 Journal Article %J Metrologia %D 2017 %T Development of a new UHV/XHV pressure standard (cold atom vacuum standard) %A Julia Scherschligt %A James A Fedchak %A Daniel S Barker %A Stephen Eckel %A Nikolai Klimov %A Constantinos Makrides %A Eite Tiesinga %X

The National Institute of Standards and Technology has recently begun a program to develop a primary pressure standard that is based on ultra-cold atoms, covering a pressure range of 1 x 10-6 to 1 x 10-10 Pa and possibly lower. These pressures correspond to the entire ultra-high vacuum range and extend into the extreme-high vacuum. This cold-atom vacuum standard (CAVS) is both a primary standard and absolute sensor of vacuum. The CAVS is based on the loss of cold, sensor atoms (such as the alkali-metal lithium) from a magnetic trap due to collisions with the background gas (primarily H2) in the vacuum. The pressure is determined from a thermally-averaged collision cross section, which is a fundamental atomic property, and the measured loss rate. The CAVS is primary because it will use collision cross sections determined from ab initio calculations for the Li + H2 system. Primary traceability is transferred to other systems of interest using sensitivity coefficients.

%B Metrologia %V 54 %8 2017/11/3 %G eng %U https://arxiv.org/abs/1801.10120 %N 6 %R https://doi.org/10.1088/1681-7575/aa8a7b