The New XRay Guy Peter Mller Peter Mueller

The New X-Ray Guy Peter Müller Peter Mueller 4. Göttingen 3. Kasierslautern 1. Frankenthal / Mannheim 2. La Chapelle Aux Bois

The New X-Ray Guy

The New Cryostream

And now: Some Crystallography • Judging the Quality of a Crystal. • Determining the Best Exposure Time. • Data Collection Strategy.

Judging the Quality of the X-tal Initial Immages Take two immages 90° appart.

Judging the Quality of the X-tal The Rocking Curve Analyze Rocking Number of frames in both directions Size of the halfwidth = box mosaicity

Determining the Exposure Time Compare two (or more) File Analyze Display Contrast File immages 10 that 20 30 seconddiffer frame only Display Contrast Display in exposure time. Does a longer exposure time add information to the immage?

Determining the Exposure Time 20 Always seconds collect is better a new than dark 10 current seconds. at your exposure time or at 30 least seconds load annot older better than (but not 20 sconds. too old!) dark current taken at Our yourexposuretime. is 20 seconds per frame. compare

Collect Dark Current Detector Dark Current Now you are ready for data collection What is the best strategy?

The Platform Geometry omega phi

phi- and omega-scans are orthogonal hkl reciprocal lattice point Diffracted beam hkl reflection Omega-scans at different phi-angles Detector s Phi-scans at different omega-angles Q Incident beam C P s d O Crystal hkl lattice planes Ewald sphere with radius r = 1/l Reciprocal lattice . . . try to combine them!

Collect Dark Current Edit Multi Run Three 200° omega-scans and two 360° phi-scans that‘s plenty for any situation. Two 200° omega-scans and one 360° phi-scan is enough for mmm and higher.

The Zero-Frames

The Zero-Frames

We have a new HOMEPAGE http: //web. mit. edu/x-ray

Next Meeting Tuesday November 9, 11: 00 a. m. AMDUR room (here) Data Reduction with SAINT and SADABS