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Axial CO-2 in alpha-particle irradiated calcite: Potential use in ESR dating

1990; Pergamon Press; Volume: 17; Issue: 4 Linguagem: Inglês

10.1016/1359-0189(90)90012-m

1878-1691

R. Debuyst, P. De Cannière, Fernand Dejehet,

X-ray Spectroscopy and Fluorescence Analysis

At room temperature, two paramagnetic centres attributed to two kinds of CO-2 radical-ions, an axial one and an orthorhombic one, are observed in a 210Po (α-emitter)-doped synthetic calcite. A subsequent γ-ray irradiation of a few KGy does not affect the intensity of the axial species, whereas it increases the orthorhombic one. A single γ-ray irradiation up to ≈ 10 kGy of non-doped synthetic calcite only produces the orthorhombic centre. Consequently, dating might be possible using the axial CO-2 signal (if stable enough), which is sometimes visible in natural calcite. Therefore, "accumulated doses" should be obtained by means of α-particle bombardments, and the annual dose merely estimated from the U-Th content of the sample itself.