The GSU K-Ar Geochronology laboratory published its first data ca 2010.
Samples are weighed with a Mettler analytical balance accurate to 0.1 mg. Samples are dissolved for potassium measurement in a fume hood rated for perchloric acid in 615KH. Argon isotopic composition is measured with a mass spectrometer connected to a high vacuum extraction line. This allows the measurement of a larger dynamic range of Ar ion beam signal on much smaller (and thus likely purer) and younger sample aliquots.Their second advantage is the ability to measure the 36Ar on the CDD multiplier while other masses are measured on the faraday detectors, resulting in analytical precision one order of magnitude better than with previous generation instruments.
C., 2007 Age of the Ocmulgee Limestone (Georgia Coastal Plain) based on revised methodology for the K-Ar age of glaucony: Southeastern Geology, v.