AVS 50th International Symposium
    Vacuum Technology Thursday Sessions
       Session VT+MS-ThM

Paper VT+MS-ThM7
Characterisation of a Fully Automated, Static Expansion Vacuum Standard at the National Physical Laboratory, UK

Thursday, November 6, 2003, 10:20 am, Room 323

Session: Reproducibility, Precision, and Accuracy of Vacuum and Process Measurements
Presenter: J.C. Greenwood, National Physical Laboratory, UK
Authors: J.C. Greenwood, National Physical Laboratory, UK
P. Carroll, National Physical Laboratory, UK
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A new, fully automatic, Static Expansion vacuum standard has recently been constructed to replace the existing manually operated system. The new instrument incorporates a number of design improvements which will be described. It is of all metal construction and operates from atmospheric pressure down into the UHV region. This paper discusses some of the procedures and measurements that have been performed to characterise the new standard. These include; mapping temperature distributions across and between the parts of the system; measuring the effects of inter-vessel valves on the pressure distribution; developing an improved measurement equation for the pressure generated in the standard, and comparison against existing vacuum standards that have been involved in recent international comparisons. We will show that calibration results taken from the new standard and the existing standards are equivalent.