Proposal of a new analytical method for rare earth elements and a provenance search for geological materials using thermo-luminescence phenomena

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Thermoluminescence (TL) phenomena were investigated from viewpoints of the fundamental emission properties using some deviced measuring methods. Firstly, a TL color image (abbreviated to TLCI here) photography was developed by using a conventional photographing system and a highly sensitive color film. When the TLCIs of various natural quartzes were observed, a noticeable finding was of two different color images, which were readily distinguishable as red and blue TL-emitting grains. Secondly, more quantitative TL-analyses were carried out by means of photon-counting apparatus connected with a personal computer and a ceramic heater. It was revealed that the beta-quartzes in the original always indicate a red TLCI, whereas alpha-quartzes in the original (pegmatite origin and granite strata) give a typical blue TLCI. From chemical analyses, it was found that the red TL-emitting quartz had higher contents of rare earth elements (REEs) than blue group. The red TL groups are also verified to be preferable for the TL-chronology instead of blue ones, which have been commonly utilized. Thirdly, a photonic multichannel analyzer (PMA) was developed for the online multi-spectrometry of extremely weak light like TL. Some impuritiy elements, extracted from both blue and red TL quartzes, were doped to synthetic quartz glasses using a sol-gel method. These synthetic glasses were subjected to the PMA analysis after the artificial irradiation. It was noteworthy that both synthetic glasses unexpectedly gave almost similar spectrum changes consisting of three peaks at longer wavelength regions contrary to the natural blue and red TL-quartzes possessing respective single broad peak.