ILL liquid instrument: FIGARO, SuperAdam (pseudoGISANS), D22 GISANS, recently latter two
FIGARO: white beam 2-30A, 0.8 to 10% spread
sub-ms pulsed neutron by chopper, time of flight for wavelength, pulse width tunable for energy spread of 0.8 ~ 10%
supermirrors bending beam up or down to strike the interface on both sides: up to 4deg
enormous effort on antivibration: concrete, passive pads, active table (slide 2)
detector: resolution 1x4mm 2D detector up to 2.8m
publications / proposals: soft matter 55%, biology 35%, chemistry 5%, nuclear physics 5%
(1) NR accesses surface excess directly!
using zero-SLD water (8% D2O in H2O), R ~ (surface excess)^2 in small q
(2) Anton Paar rheometer combined with Kibron trough: double wall ring rheometer (P. Sanchez-Puga, Journal of Applied Crystallography, 2026, in print)
liquid surface between the double wall is connected to main trough surface to equilibrate the film
surface width between the double wall: 3mm, > capillary length of water
ring on the surface in the double wall, with 3% strain oscillation, ~ on the order of 30um
negligible effect of vibration causes by the rheometer at this amplitude (https://arxiv.org/abs/2411.04660)
(3) Lung surfactant with QT trough: change of meniscus and associated height change is a problem – laser interferometer to set the height within 10um (not better at FIGARO), sufficient as neutron beam is centimeter high, and the incidence is ~ 1.2deg or 3deg
(4) offspecular scattering: the in-plane resolution is stretched to a few 10s of microns in the longitudinal direction, therefore offspecular is done in the plane of incidence to see large structures.
(4) offspecular scattering: the in-plane resolution is stretched to a few 10s of microns in the longitudinal direction, therefore offspecular is done in the plane of incidence to see large structures.