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Shripalkumar N. Desai
Shripalkumar N. Desai
Diamond Valuer and Trustee, Bachelor of Engineering
Gemmological Institute of India
Diamond Valuer and Trustee, Bachelor of Engineering
Gemmological Institute of India
Mumbai
India

Articles

Geology
  • Date submitted
    2023-02-10
  • Date accepted
    2023-09-20
  • Online publication date
    2024-01-10
  • Date published
    2024-04-25

Depth distribution of radiation defects in irradiated diamonds by confocal Raman spectroscopy

Article preview

Five colored diamonds were investigated. According to the results of the study by FTIR, UV-Vis-NIR and Photoluminescence spectroscopy, they are natural type Ia diamonds. The depth distribution of the color intensity was carried out by measuring the intensity of the PL peak at 741 nm (GR1 center) upon excitation by a laser with a wavelength of 633 nm of Raman Confocal microscope. To minimise the perturbation due to geometrical effects, defect distribution profiles were normalised with respect to diamond Raman peak intensity (691 nm) point by point. For two diamonds, the intensity of the GR1 peak (741 nm) sharply decreased to a depth of 10 µm, and then became equal to the background level, which is typical for irradiation with alpha particles from natural sources like uranium. In other diamonds, the profiles vary slightly with depth, and the color intensity is close to uniform, which is for irradiation with accelerated electrons or neutrons. The source of radiation has not been determined. However, long duration radioactivity measurements of the diamonds suggested that neutrons were not used for colour centers production in the diamonds studied.

How to cite: Ardalkar R.M., Salunkhe Y.D., Gaonkar M.P., Mane S.N., Ghaisas O.A., Desai S.N., Reddy A.V.R. Depth distribution of radiation defects in irradiated diamonds by confocal Raman spectroscopy // Journal of Mining Institute. 2024. Vol. 266. p. 179-187. EDN XGGRVF