You probably have to tilt your crystal, so that the long axis is
parallel to the beam. We do this routinely: cut a plastic pipette tip
to have a sharp point, then push the loop where it attaches to the pin,
to bend the crystal itself.
You have to identify from your diffraction whether the long axis is
pointing through the face or the edge of the loop. As it's P6, chances
are it's through the face, because long-axis P6 tends to make flat
hexagons which lie flush with the face. So you have to bend so the face
of the loop upwards.
You'll have to practice this first, though, so put up an empty loop.
Top tips:
* Don't breathe! You'll blow the cryostream away.
* Bend the loop towards (rather than away from) the rim edge of the
pin to which it's glued.
* Don't breathe!
* Practise practise practise.
Another thing: most in-house sources allow you to reduce divergence of
the beam. You lose intensity, but no matter, just expose longer. That
also improves overlap.
Cheers
phx
On 07/03/2012 04:56, Dipankar Manna wrote:
Dear Crystallographers,
I am working on a protein having SG P6, the cell parameters are a= 79,
b= 79, c= 325. The crystals are forming in big size and with very good
shape. It also diffracting very well in Home source facility both in
terms of resolution and intensity. But the only problem is the number
of overlaps. Its showing much more than the good spots. As a result
the completeness is showing maximum up to 65% even after collecting
180 degrees. I am unable to get a complete data. I tried with reducing
the oscillation angel to 0.3 degree/0.5 degree but it did not improve
that much. Please give me some suggestions.
Regards,
Dipankar
/Dipankar Manna/
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