Optical calibration of pressure sensors for high pressures and temperatures

Abstract

We present the results of Raman scattering measurements of diamond (12 C) and of cubic boron nitride (cBN), and fluorescence measurements of ruby, Sm:YAG, and SrB 4 O 7 :Sm 2+ in the diamond anvil cell (DAC) at high pressures and temperatures. These measurements were accompanied by synchrotron x-ray diffraction measurements on gold. We have extended the room-temperature calibration of Sm:YAG in a quasihydrostatic regime up to 100 GPa. The ruby scale is shown to systematically underestimate pressure at high pressures and temperatures compared with all other sensors. On this basis, we propose a new high-temperature ruby pressure scale that should be valid to at least 100 GPa and 850 K.

Carbon precipitation from heavy hydrocarbon fluid in deep planetary interiors

“…Our setup enables us to keep the pressure-loading mechanism of the DAC at much lower temperatures than reached in the sample chamber, thus significant pressure stability during RH DAC experiments was achieved. Temperature-corrected ruby barometer 19 was employed to determine pressure in RH experiments; temperature was measured using a S-type thermocouple attached to a diamond anvil near the tip (o±1 K).…”

“…The discrepancy between the results obtained by LH DAC, shockwave, MD and thermodynamics may arise from various assumptions in modelling as well as from kinetic, catalytic and analytical problems in the experiments. Recent advances in resistively heated (RH) and LH techniques allow for better control of P-T conditions in DAC cavity 19,20 , as well as for more accurate characterization of the physico-chemical processes than previously possible.…”

Review: Coefficients for Stress, Temperature, and Composition Effects in Fluorescence Measurements of Alumina

“…In the early 1970s, the process was turned around somewhat, and the details of crystal field theory were overtaken by empirical advances. In particular, calibrated experimental determination of shifts in the R1 and R2 line energies, , as a function of hydrostatic pressure [16][17][18][19][20][21][22] became the standard method for measuring pressure in high-pressure experiments involving the diamond anvil cell (DAC)-a method that continues to this day [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37], although not without debate regarding calibration coefficients. (Here and throughout, citations within a topic are given in chronological order of publication.)…”

Hydrogenation of Graphene by Reaction at High Pressure and High Temperature

“…3 In its most intense location, the I D /I G ratio for graphene hydrogenated by high pressure and high temperature in Figure 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 8 in the Y2 line of Sm:YAG. 19 A more intense D peak (I D /I G = 2.3) as well as the emergence of the D` peak is observed under these conditions. Although the reaction at 2.6 GPa was carried out over a much longer time period, there is a marked difference in the D peak intensity -and thus the hydrogenation levels -between those samples and the samples treated at 4.0 and especially 5.0 GPa at the same temperature, allowing us to infer that pressure has an influence on the reaction rate with hydrogen or on the maximum possible extent of the reaction.…”

“…Samples for diamond anvil cell experiments were formed by cutting suitably small (typically 200 µm) sections of graphene-coated Cu substrate using a fine-point needle, and then verifying using Raman spectroscopy that no damage had occurred to the monolayer graphene.Photoluminescence and Raman spectroscopy. Photoluminescence measurements on a ruby crystal in the sample chamber to determine pressure 17 were performed using 532 nm solid state laser, photoluminescence measurements on Sm:YAG were performed with 405 nm solid state laser 19. Spectra during experiments were collected on either a Horiba iHR320 with Symphony CCD or Andor Shamrock-303i-A with iDUS CCD, utilizing a Mitutoyo 10x objective lens (f = 200 mm).…”