A constant pressure flowmeter for extreme-high vacuum

We demonstrate operation of a constant-pressure flowmeter capable of generating and accurately measuring flows as low as 2 × 10 mol/s. Generation of such small flows is accomplished by using a small conductance element with ≈ 50 nL/s. Accurate measurement then requires both low outgassing materials...

Full description

Saved in:
Bibliographic Details
Published inMetrologia Vol. 59; no. 4; pp. 45014 - 45023
Main Authors Eckel, S, Barker, D S, Fedchak, J, Newsome, E, Scherschligt, J, Vest, R
Format Journal Article
LanguageEnglish
Published England IOP Publishing 01.08.2022
Subjects
Compressibility
extreme-high vacuum
High vacuum
Hydraulic equipment
Outgassing
ultra-high vacuum
Uncertainty
vacuum flowmeter
vacuum measurement
Online AccessGet full text

Cover

More Information
Summary:We demonstrate operation of a constant-pressure flowmeter capable of generating and accurately measuring flows as low as 2 × 10 mol/s. Generation of such small flows is accomplished by using a small conductance element with ≈ 50 nL/s. Accurate measurement then requires both low outgassing materials (< 1 × 10 mol/s) and small volume changes (≈ 70 L). We outline the present flowmeter's construction, detail its operation, and quantify its uncertainty. The type-B uncertainty is < 0.2 % ( = 1) over the entire operating range. In particular, we present an analysis of its hydraulic system, and quantify the shift and uncertainty due to the slightly compressible oil. Finally, we compare our flowmeter against a NIST standard flowmeter, and find agreement to within 0.5 % ( = 2).
Bibliography:Bureau International des Poids et Mesures
MET-102104.R3
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0026-1394
1681-7575
DOI:10.1088/1681-7575/ac7927