Pressure disequilibria induced by rapid valve closure in noble gas extraction lines
Pressure disequilibria during rapid valve closures can affect calculated molar quantities for a range of gas abundance measurements (e.g., K-Ar geochronology, (U-Th)/He geochronology, noble gas cosmogenic chronology). Modeling indicates this effect in a system with a 10 L reservoir reaches a bias of 1% before 1000 pipette aliquants have been removed from the system, and a bias of 10% before 10,000 aliquants. Herein we explore the causes and effects of this problem, which is the result of volume changes during valve closure. We also present a solution in the form of an electropneumatic pressure regulator that can precisely control valve motion. This solution reduces the effect to ∼0.3% even after 10,000 aliquants have been removed from a 10 L reservoir.
Citation Information
Publication Year | 2015 |
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Title | Pressure disequilibria induced by rapid valve closure in noble gas extraction lines |
DOI | 10.1002/2015GC005823 |
Authors | Leah E. Morgan, Brett Davidheiser-Kroll |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Geochemistry, Geophysics, Geosystems |
Index ID | 70177791 |
Record Source | USGS Publications Warehouse |
USGS Organization | Central Mineral and Environmental Resources Science Center |