Ar ar dating technique
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.
For larger aliquot of minerals ( The Facility recently acquired an ARGUS VI (Thermofisher), a new generation low volume Multiple Collector Noble Gas Mass Spectrometers (MC-NG-MS) equipped with 5 faraday cups and one CDD multiplier that has recently become commercially available, offering three advantages.
Their first advantage is a better sensitivity of the new generation of CDD electron multipliers and 10^12-ohm resistor faraday collectors.
The isotopes the KAr system relies on are Potassium (K) and Argon (Ar).
The method relies on satisfying some important assumptions: Given careful work in the field and in the lab, these assumptions can be met.
The rock sample to be dated must be chosen very carefully.
What simplifies things is that potassium is a reactive metal and argon is an inert gas: Potassium is always tightly locked up in minerals whereas argon is not part of any minerals. So assuming that no air gets into a mineral grain when it first forms, it has zero argon content.
That is, a fresh mineral grain has its K-Ar "clock" set at zero.