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Hi, Another simple suggestion: Could it just be anisotropic diffraction? If your using 1degree oscillations, after 30 to 40 frames you may just expose the crystal to an unfavorable orientation. Anisotropy vs radiation damage is easy to check by collecting directly 5 images at 0, 45, 90, 135, 180 degree. Good luck, Pierre. > Dear bulletin members, > > Sorry for non-CCP4 related questions. > Recently, I've got crystals which have a radiation damage problem. > It also has a weak diffraction because of the big unit cell dimension > (about 300A in one direction), so I have to overexpose crystals even with > the synchrotron beam. The problem is that during the data collection, the > resolution decaded gradually from 3 to 6A after certain number of frames > (about 30 or 40 frames). Do you have any experiences or any suggestions > that I can evade this radiation damage? Any suggestions will be grateful. > Thank you. > > Best regards, > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Uhn-Soo,Cho > Graduate student in Biological Structure Department > University of Washington. > HSB G514 > 1959 NE Pacific St. > Seattle, WA 98195-7420 > Box. 357420 > Fax #206-543-1524 > Tel # 206-221-2435 > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- Pierre Legrand - Proxima 1 Synchrotron SOLEIL - L'Orme des Merisiers Saint-Aubin - BP 48 - 91192 GIF-sur-YVETTE CEDEX Tel: 01 69 35 96 60 Fax: 01 69 35 94 56
