Developmental of high precision incremental heating device for Ar-Ar single mineral dating

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It is most important to analyze argon isotopes in gas phase fractions extracted from a single mineral by incremental heating for highly reliable Ar-Ar dating. This study is to develop a high precision incremental heating device with the temperature control system by using a laser probe heating apparatus and an infrared thermometer and to apply it to Ar-Ar single mineral dating. We have bought the main apparatuse of an infrared thermometer and then carried out the basic experiments using it and the former laser probe heating apparatuse. The new device to be developed makes it possible to measure the high temperature range using only the detector for medium temperature of infrared thermometer though the commercial base infrared thermometer has required the high temperature detector to measure the temperatures. This case follows our original idea to use a specific filter in measuring the high temperatures. In the calibration for energy loss of infrared rays coming through the filfter, we … More did not choose to re-write the program installed in the converter and does in stead to make a calibration curve between the true temperature and the out put voltage. This makes it possible to measure precisely and easily the sample temperatures controlled by laser incremental heating. This technique has been applied to Ar-Ar mineral dating of natural samples and some results have been presented at conferences.In proceeding this project, there is a by-product ; we had to modify slightly the content of this project. This lead us to recognize a economical but precise quadruple mass spectrometer for qualitative and quantitative analyzes of gas species extracted from specimens in meddium temperature range. This mass spectrometer makes it possible to measure immediately mass spector of gas species of which the intensity change quickly in time and to estimate the absolute abundance of each gas species at the time zero when the gas was introduced into the mass spectrometer. In highly reliable Ar-Ar dating, it is neccessary to take the age spectrum for many incremental heating gas fractions, requiring decreasing of analysing time of each fraction. This new mass spectrometer makes it possible to evaluate the gas purification time before introducing the gas into mass spectrometer. Less