Absolute dating radiocarbon dating. The development of accelerator mass spectrometry (AMS) dating, which allows a date to be obtained from a very small sample, has been very useful in this regard. Other radiometric dating techniques are available for earlier periods. One of the most widely used is potassium–argon dating (K–Ar dating). Potassium-40 is a radioactive isotope of potassium that decays into argon-40. The half-life of potassium-40 is 1.3 billion years, far longer than that of carbon-14, allowing much older samples to be dated. Potassium is common in rocks and minerals, allowing many samples of geochronological or archeological interest to be dated. Argon,
High Flux Isotope Reactor monitoring and enables individual inspectors to obtain large numbers of samples in the hopes of finding required evidence. By screening those samples, the very high costs of destructive analysis are required only for those samples deemed interesting. Delayed neutron analysis is becoming increasingly useful for these studies. A recent application involves the irradiation of programmable memory devices that have been coated with a small amount of a fissile isotope. The fission events induced upon irradiation may be tracked spatially by comparing the values in memory with those assigned to memory initially; areas of differences are attributed to damage caused by