Measurement of temperature in the laser heated diamond anvil cell: comparison between reflective and refractive optics

Ruggero Giampaoli*, Innokenty Kantor, Mohamed Mezouar, Silvia Boccato, Angelika D. Rosa, Raffaella Torchio, Gaston Garbarino, Olivier Mathon, Sakura Pascarelli

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

In this article we present a direct comparison between reflective (Schwarzschild mirrors) and refractive (achromatic doublets) optics commonly used in spectroradiometric temperature measurements in laser heated diamond anvil cells. Emission spectra are fitted with the Planck's law and are further analysed with the two-colour technique; theoretical simulations are used to compare the temperature measurement accuracy of the two optical systems. The first result obtained is that achromatic doublets with large numerical aperture (NA approximate to 0.2) produce extensive accuracy errors in the full T range (1500-3000K). When reduced apertures (NA = 0.8) are used a good agreement is found with measurements from reflective optics up to 2600K while systematic differences (around 200K) appear at higher temperatures. However, these temperature differences cannot explain the discrepancies between the iron melting curves obtained in the past years using laser heated diamond anvil cells.
Original languageEnglish
JournalHigh Pressure Research
Volume38
Issue number3
Pages (from-to)250-269
Number of pages20
ISSN0895-7959
DOIs
Publication statusPublished - 2018

Keywords

  • Laser heating
  • Temperature gradients
  • Spectroradiometry
  • Pyrometry
  • Chromatic aberrations
  • Melting curve

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