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Etching of fission tracks in monazite: An experimental study
Author(s) -
Jones Sean,
Gleadow Andy,
Kohn Barry,
Reddy Steven M.
Publication year - 2019
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12382
Subject(s) - monazite , annealing (glass) , etching (microfabrication) , fission , materials science , isotropic etching , grain size , mineralogy , isothermal process , analytical chemistry (journal) , metallurgy , geology , composite material , chemistry , neutron , geochemistry , nuclear physics , thermodynamics , zircon , layer (electronics) , chromatography , physics
This study reports a range of etching and annealing experiments to establish the optimum conditions for the etching of fission tracks in monazite. The previously reported concentrated (12 M) HCl etchant at 90°C was found to cause grain loss from epoxy mounts and high degrees of grain corrosion, as did much longer etching times at lower temperatures. Using implanted 252 Cf semi‐tracks, a series of experiments were performed on internal prismatic faces of monazite‐(Ce) crystals from the Palaeozoic Harcourt Granodiorite (Victoria, Australia) using an alternative 6 M HCl etchant, also at 90°C. Step‐etch results show optimal etching at 60–90 min. Further, an isothermal annealing experiment illustrated that the degree of annealing that can be expected during etching at 90°C under laboratory time scales is negligible. The etching rate between grains is not uniform, with a correlation demonstrated between over‐etched grains and high U and Th concentrations.