We have designed and regularly upgrade an in-house SAXS experiment for high sensitivity measurements.
The generator is a copper rotating anode Rigaku RUH3R, with a fine focus filament.
The optic is composed by an Xenocs collimating multilayer mirror, coupled with home made hybrid cristal slits.
The source – sample distance is around 200 cm. We take attention to reduce the air quantities between the sample and the vacuum chamber. In this way we designed a retractable nose, let us change the sample environment. We can propose multi-position capillary holder, powder holder, heating system, thermostated system, circulation chamber,…
The beam size on the sample is 0.8 mm x 0.8 mm and the X-ray flux of the order of 100×106 ph/s. The vacuum chamber contains a beamstop with a small calibrated photodiode.
The distance to the detector is 120 cm, and the q range is from less to 10-2 Å-1 to 0.7 Å-1.
See : What is measured in a Small Angle X-ray Scattering (SAXS) ?
Detector :
We use a Mar 300, automatic image plate reader, that produce a good resolution (0.150 mm), a good sensitivity (efficienty around 90%), but a high background level.
Ins some cases, a gas detector can be used, with a very low background level.
Reference samples :
- Lupolen is a solid polymer, wich produce a slope at I = 6cm-1
- Tetradecanol, or commonly myristyl alcohol, is a straight-chain saturated fatty alcohol, with the molecular formula C14H30O, and organized as a well structrured lamellar phases. SAXS spectra gives very fine peaks. First order is 0.1581 Å-1
Data treatment
Two softwares are developed for the data treament: