FIGARO - Fluid Interfaces Grazing Angles ReflectOmeter
FIGARO - Fluid Interfaces Grazing Angles ReflectOmeter
Figaro is a high flux, flexible resolution, time-of-flight reflectometer with a vertical scattering plane. It is optimized for the study of horizontal surfaces such as free liquids. No polarized neutron option is available currently nor is foreseen in the near future. The instrument includes the possibility to strike the interface from above or below the sample in a wide q-range. With an incoming beam of wavelengths comprised between 2 Å and 30 Å, and M=4 supermirrors to deflect the beam, it is possible to attain a q-range up to 0.42 Å-1 (reflection up) or 0.27 Å-1 (reflection down) for horizontal samples, and an even broader q-range can be achieved for solid samples which can be tilted using one of the sample goniometers.
The sample area includes an active anti-vibration table and free liquid surfaces are aligned automatically using an optical device. The 2D neutron detector allows the acquisition off-specular scattering and GI-SANS data.
Applications
- Specular scattering from 'free liquid' (air/liquid, liquid/liquid) samples but also air/solid and solid/liquid interfaces;
- Off-specular' scattering and GISANS from the above sample types;
- Kinetics phenomena on a minute or slower time scale.
3D drawing of the instrument
No general view is available for this instrument since it is covered by 45 tons of lead.
A guide curved horizontally and vertically feeds neutrons to the instrument. There is a choice of two frame overlap mirrors which remove neutrons above specific wavelengths. A four-chopper assembly generates pulses with a choice of optimum flux or resolution. Two deflector mirrors direct the neutrons upwards or downwards towards the sample. A collimation guides focuses the beam in the horizontal plane. The sample position has a range of sample environments with many of them optimised for free liquid surfaces. An evactuated flight tube reduces air scattering after the sample. Lastly, a detector captures 2D images of neutron reflectivity.
The neutron optics of FIGARO
The neutrons travel from the right to the left through this assembly comprising the frame overlap mirrors, the choppers, the deflector mirrors and the collimator guide.
The sample zone
The sample zone of FIGARO can accomodate various types of sample setups. The vertical scattering plane makes it possible to work on free liquid surfaces.
- detector nose
- Langmuir trough for the study of insoluble monolayers
- slit of the incoming neutron beam
- active antivibration table