<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Brett Davidheiser-Kroll</dc:contributor>
  <dc:creator>Leah E. Morgan</dc:creator>
  <dc:date>2015</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;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.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1002/2015GC005823</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>AGU Publications</dc:publisher>
  <dc:title>Pressure disequilibria induced by rapid valve closure in noble gas extraction lines</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>