Hi Mohamed,

On 7/28/2015 3:02 AM, Ivanov wrote:

I suggest you collect a dataset at 7kev (around 2.0A) which is the absorption edge of S.

The absorption edge of sulfur is at 2.472 keV, which is 5.0155 A...

I suggest you ask the beamline scientist, which wavelength is suitable. Maybe the beamline can be tuned to 2.5 A, but the flux might become weak. Furthermore, absorption of X-rays in air (and the sample) is strong for wavelengths above 2.0 A.

If kappa goniometer is available, I would use it. You can also collect data from several crystals, or several data sets at different spots from one crystal.
I think it is difficult to give recommendations about the multiplicity you need. Collect data, then process and try to find the substructure during your beamtime. If you cannot find the substructure and solve the structure, collect more data and combine data sets.

Hope that helps,

Dorothee

On 27 July 2015 7:17:18 pm mohamed noor <[email protected]> wrote:

Dear all

Would you have some tips on collecting datasets for S-SAD at a 'normal' beamline (tunable from 0.5-2.5 A)? How helpful/important is it to use mini kappa?

Thanks.