Schematic representation of the multichannel collimator (MCC) in angular dispersive geometry with a monochromatic beam. It is composed of 75 channels. The width of the inner (outer) slits is, respectively, 50 μm (200 μm).
Intensity of the various 2θ diffraction peaks from an LaB6 diffraction standard as a function of the x-position of the MCC. The optimum position, shown by the red line, is taken as that which maximizes the diffraction intensity.
X-ray diffraction pattern of liquid argon, recorded with and without the PE-MCC. Dotted lines represent the corresponding background, dominated by the contribution of Compton scattering from the anvils.
Schematic description of the dispersion angle, ϕ, that can pass through a given channel of the MCC, obtained for a particular position along the x-ray beam. The origin corresponds to the rotation axis of the MCC.
2D countour of the dispersion angle ϕ (in rad.) of light that passes through the MCC, calculated as a function of the diffraction angle 2θ (horizontal axis) and of the position along the x-ray beam (vertical axis).
Contour plot of χ2 for argon at 0.9 GPa. (a) As a function of the reference (s 0th ) and sample (s th ) thicknesses. (b) As a function of the atomic density, ρ0, and the thickness, s th . Red crosses show the position of the minimum of χ2(ρ0, s th ) in ρ0-s th space calculated for various values of s 0th . Note that χ2 is normalized such that χ2 = 1 at the minimum.
The optimum density ρ0 (bottom-left axis), scale factor s (bottom-right axis), sample thickness s th (left-top axis), and the corresponding normalized χ2 for argon at 0.9 GPa as a function of Q max .
Results of our experiments on argon at 0.9 GPa. (a) The structure factor S(Q). (b) The radial distribution function g(r). The solid and dotted blue lines show the data taking into account and neglecting the MCC contribution, respectively. The dashed red line corresponds to the data obtained without the MCC, as reported by Eggert et al. 8 and performed at 1.1 GPa.
Measured x-ray diffraction pattern of a liquid H2 sample at 3.5 GPa in the DAC. The red line is the raw data. The black line is the reference signal measured from the empty DAC. The dashed black line is the background signal calculated with Eq. (12) . (Inset) Hydrogen scattered signal (after subtraction of the background contribution).
Pressure evolution of the structure factor of liquid hydrogen at ambient temperature. The dots are experimental data and the full lines are the experimental data smoothed.
(Q/Q 0)3 plotted against ρ/ρ0, where Q represents the position of the first peak in the hydrogen structure factor, and ρ represents the liquid density calculated from the Pratesi equation of state. 19
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