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Time‐gated Raman and laser‐induced breakdown spectroscopy in mapping of eudialyte and catapleiite
Author(s) -
Romppanen Sari,
Häkkänen Heikki,
Kekkonen Jere,
Nissinen Jan,
Nissinen Ilkka,
Kostamovaara Juha,
Kaski Saara
Publication year - 2020
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.5622
Subject(s) - raman spectroscopy , fluorescence , analytical chemistry (journal) , laser , raman scattering , signal (programming language) , excited state , materials science , picosecond , chemistry , optics , atomic physics , physics , chromatography , computer science , programming language
Raman analysis of rock samples containing rare earth elements (REEs) is challenging due to the strong fluorescence, which may mask the weaker Raman signal. In this research, time‐gated (TG) Raman has been applied to the construction of the mineral distribution map from REE‐bearing rock. With TG Raman, material is excited with a short subnanosecond laser pulse, and the Raman signal is collected within a picosecond‐scale time window prior to the formation of a strong fluorescent signal by means of single‐photon avalanche diode array. This allows signal readout with a significantly reduced fluorescence background. TG Raman maps are used to reveal the location of valuable minerals and are compared with the elemental distribution given by laser‐induced breakdown spectroscopy. The analysis was carried out from a REE‐bearing rock, nepheline syenite sample from the Norra Kärr deposit, where REEs are mainly hosted in eudialyte and catapleiite. The combination of these two complimentary laser spectroscopic methods offers valuable elemental and mineralogical information about rocks.