THERMOLUMINESCENCE (TL) SPECTRA FROM QUARTZ GRAINS USING ONLINE TL-SPECTROMETRIC SYSTEM

An on-line spectrometric system installed with a small spectrometer an d an image intensifier unit has been developed for weak and changeable TL-spectrum measurements with rising temperature for application to n atural minerals. The detection sensitivity over visible wavelength reg ions was corrected using a known spectrum from a standard light source , and the detection sensitivity was also examined by a chemical lumino l reaction. In an applied experiment, two quartz grain samples from tw o pyroclastic flows of the same origin, were subjected to testing with the present measuring system. The original data, consisting of 512 ch annels for every second at a constant heating rate of 1 degrees C/s, w ere used to create a contour map or a 3-dimensional expression of TL-s pectra after subtraction of background radiation. The artificially irr adiated quartz grains clearly showed both red (RTL) and blue TL (BTL) in contrast to RTL alone from naturally accumulated TL. Both spectral expressions and glow curves from the same original data were found to be available to estimate quartz formation temperatures, together with thermoluminescence colour images (TLCIs).