Argon argon dating
220.127.116.11 , 16 December 2005 (UTC) I believe it is gamma radiation; and you do not have to know the K ratio in advance, as you can do a correction for it with the internal Ar ratios of the sample, and a correction for Chlorine-37, etc, etc.
You also need a flux monitor to calculate the radiation flux (or J-constant) of the reactor which describes the efficiency of the irradiation.
Argon-argon dating works because potassium-40 decays to argon-40 with a known decay constant. This led to the formerly-popular potassium-argon dating method.
However, scientists discovered that it was possible to turn a known proportion of the potassium into argon by irradiating the sample, thereby allowing scientists to measure both the parent and the daughter in the gas phase.
is known to cause grave problems in regional geochronology studies.The quantity of potassium in a rock or mineral is variable proportional to the amount of silica present.Therefore, mafic rocks and minerals often contain less potassium than an equal amount of silicic rock or mineral.Argon can mobilized into or out of a rock or mineral through alteration Ar and potassium, there is not a reliable way to determine if the assumptions are valid.Argon loss and excess argon are two common problems that may cause erroneous ages to be determined.