Development and Applications of Time-Resolved M ssbauer Spectroscopy

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a time-resolved Mossbauer spectroscopy is considered to be very useful for unconventional Mossbauer experiments such as delayed coincidence and fast velocity-channel sweep experiments. In this project we developed a low cost and versatile Mossbauer spectrometer using a one-board microprocessor and a personal computer, which enables us to make multi-parameter and fast velocity-channel sweep experiments.Our system is operated under a program control and allows us to choose two different modes by substituting the program.Normal mode: Usual Mossbauer spectra are obtained in this mode. The system operates as multiscalers and features a capability for simultaneous recording of multiple independent spectra.Event processing mode: This mode is useful for recording a spectrum with fast velocity-channel sweep, and a multi-parameter measurement is also easily accomplished. When an event ( -ray detection) occurs, the data of the momentary velocity and the other experimental parameters such as time, temperature and fields, if required, are stored in the microprocessor, and then processed in accordance with the purpose of the experiment using the personal computer. For example, in a delayed-coincidence Mossbauer experiment it is necessary to divide the time scale into several intervals and record time-resolved Mossbauer spectra. Our system is also used to measure the Mossbauer spectral change after photo-dissociation of the ligand in hemoproteins such as myoglobin-CO compound, at low temperatures.