Development of a new UHV/XHV pressure standard (Cold Atom Vacuum Standard)
Julia Scherschligt, James A. Fedchak, Daniel Barker, Stephen Eckel, Nikolai Klimov, Constantinos Makrides, Eite Tiesinga
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 × 10-6 Pa to 1 × 10-10 Pa and possibly lower. These pressures correspond to the entire ultra-high vacuum (UHV) range and extend into the extreme-high vacuum (XHV). 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.
, Fedchak, J.
, Barker, D.
, Eckel, S.
, Klimov, N.
, Makrides, C.
and Tiesinga, E.
Development of a new UHV/XHV pressure standard (Cold Atom Vacuum Standard), Measurement, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=923344
(Accessed December 9, 2023)