NEW OPTION AT ID10B (TROIKA II) BEAMLINE HIGH ENERGY FOR SURFACE STUDIES AT LIQUID/LIQUID INTERFACES Oleg Konovalov, Eric Saint-Martin - ID10B, ESRF, France http://www.esrf.fr/UsersAndScience/Experiments/SCMatter/ID10B/ Jean Daillant, Daniel Luzet, Viswanath Padmanabhan - C.E.A. Saclay - DRECAM/SCM, France How we extend the available energy rainge at ID10B Double crystal monochromator ID10B layout Upgraded 2nd monochromator stage To ID10A (white beam) 2θmax 2θmin 1st mono To ID10B (monochromatic beam) 2nd mono C(111) Geometric restrictions and possible Energies MIN 22.86 7.75 12.66 θ, [deg] C(111) E, [keV] C(220) E, [keV] MAX 12.57 13.83 22.59 1st mono Topography (220) C(220) 2nd mono Topography (220) Double crystal monochromator of the ID10B beam line has two functions: 1) provide monochromatic X-ray beam and 2) be transparen to split the beam. The latter constrain together with fixed exit aperture after 1st monochromator defines the energy rainge and limit the choice of possible monochromator crystals. The use of second paire of diamond crystals with symmetric Bragg reflection (220) allows to keep transparent optics and extend the energy range from 8 – 13 keV to 8 – 22 keV. Why we need high energy at ID10B Attenuation length 1/e attenuation length, [mm] Surface scattering studeis on buried interfeces (liquid/solid, liquid/liquid or solid/solid) face with the problem of attenuation of the incident and scattered beam in the media trough which it travels. Figure on the righthand side demonstrate on an example of the liquid media that a way to overcome this problem is the use of high energy. 45 Why to study the liquid/liquid interfaces Water, H2O, 1 g/mL n-Hexadecane, C16H34, 0.77 g/mL 40 35 air 30 Liquid 1 25 20 Liquid 2 or Solid 15 10 5 0 8 10 12 14 16 18 20 The liquid-liquid interface plays an important role in many physical, chemical and biological processes of everyday life. Its characterization would enhance our understanding of fundamental processes occuring in nature. 22 Energy, [keV] Langmuir trough for Liquid/Liquid interface Experimental Results Air/oil interface Oil/water interface Movable Barrier π - pressure sensor α air X-ray beam Reflectivity hexadecane β water ψ GID and GISAXS Front view Side view Trough from Jean Daillant, C.E.A. Saclay - DRECAM/SCM Reflectivity on the Air/H2O interface Diffuse scattering on the Oil/H2O interface GID on DSPC monolayer at Air/H2O interface 0.0050 0 10 -1 10 -2 10 -3 10 -4 10 -5 10 -6 10 -7 10 -8 10 -9 0.0 Experiment Calculation (σ=3.3 A) 0.0045 Intensity, a.u. Reflectivity 10 0.0040 0.0035 0.0030 0.0025 0.0020 0.1 0.2 0.3 0.4 0.0015 8.2 0.5 8.4 -1 Qz, A Beam size 50 µm αc = 61 mdeg (Qz=0.0217 A-1) Reflectivity at the Oil/H2O interface Conclusions 0 10 9.0 GID on DSPC monolayer at Oil/H2O interface C16H34 / H2O interface C16H34 / DSPC / H2O interface 10 Energy range of the ID10B beamline extended to 22.5 keV Qc=sqrt(Qc12 - Qc22) -4 10 A-1 Qc1(H2O)=0.0217 Qc2(C16H34)=0.0195 A-1 -5 10 -6 10 -7 10 -8 10 -9 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 -1 Qz, A Beam size 15 µm αc = 20 mdeg (Qz=0.007 A-1) Surface scattering techniques on the liquid/liquid interface has been successfully tested and is available now at the ESRF only at ID10B. Obtainable flux of ~6·1010 at 20 keV is enough to performe - Reflectivity - Diffuse scattering in the plane of incidence - Diffuse scattering in the plane of surface - Grazing Incidence Diffraction (not in all cases) X-rays give 3 times larger Qz range for reflectivity and several orders of magnitudes more in dynamic range in comparison with the Neutrons (Qz<0.15, Rmin~5·105) 10 -2 10 -3 10 -4 0.026 Intensity, a.u. -3 Intensity, a.u. -2 10 Reflectivity 8.8 0.028 -1 10 10 8.6 2θ, [degree] 0.024 0.022 0.020 0.018 0.016 8.2 8.4 8.6 2θ, [degree] 8.8 9.0 0.014 8.2 8.4 8.6 8.8 9.0 2θ, [degree] Figure on the left side present on the same scale GID signal on the monolayer of DSPC at the air/water interface (black curve) and the background produced with hexadecane (blue curve). Red curve is the sum of black and blue curves, which simulate expected GID signal on the monolayer of DSPC at the oil/water interface. Figure on the right side is the zoom of top curves.