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Hi, it's clearly not a detector problem (at least not an obvious one!), since the 'lines' clearly follow the *curved* path of the reciprocal lattice lines as they are projected from the Ewald sphere onto the detector. A saturated pixel would presumably affect other pixels only in the same row and would appear in *straight* lines unrelated to the reciprocal lattice. I'm sticking with diffuse scattering! Cheers -- Ian > -----Original Message----- > From: [log in to unmask] > [mailto:[log in to unmask]] On Behalf Of Stephan Ginell > Sent: 28 January 2009 17:43 > To: Margriet Ovaere; [log in to unmask] > Subject: Re: [ccp4bb] small lines in diffraction pattern > > Hi.... Such line can occur on a CCD detector if reflection > are saturating a pixel and is generally in the direction of > the detector readout. 1) what detector are you using, 2) are > reflections in the black center saturated i.e. Greater than > the dynamic range of the detector. 3) what is your exposure > time, 4) do you see such streaks on short / attenuated > exposures? 5 do you see such streaks on dark images of (no > x-rays) but same time. > Steve > > > **************************************************** > Stephan L. Ginell, Ph.D. > Coordinator, SBC User Program > Biosciences > Argonne National Laboratory > 9700 S. Cass Ave > Argonne, IL 60439 > > (630)252-3972 office > (630)218-8122 pager > (630)252-6126 Fax > [log in to unmask] Email > > On 1/28/09 7:51 AM, "Margriet Ovaere" > <[log in to unmask]> wrote: > > > > Dear all, > > In the diffraction pattern of crystals of an RNA > decamer, small lines appeared (see pictures attached). We've > tried different crystals but they all showed the same small > lines. Has anybody seen this phenomena before and has got an > explanation for it please..? > > Many thanks > > Margriet Ovaere > > > > > ________________________________ > > > > ________________________________ > > > ________________________________ > > > > ________________________________ > > > > Margriet Ovaere > Chemistry Department K.U.Leuven > Biomolecular Architecture > Celestijnenlaan 200 F > B-3001 Heverlee (Leuven) > Tel: +32(0)16327477 > > > > > > > > > > > > Disclaimer This communication is confidential and may contain privileged information intended solely for the named addressee(s). It may not be used or disclosed except for the purpose for which it has been sent. If you are not the intended recipient you must not review, use, disclose, copy, distribute or take any action in reliance upon it. If you have received this communication in error, please notify Astex Therapeutics Ltd by emailing [log in to unmask] and destroy all copies of the message and any attached documents. Astex Therapeutics Ltd monitors, controls and protects all its messaging traffic in compliance with its corporate email policy. The Company accepts no liability or responsibility for any onward transmission or use of emails and attachments having left the Astex Therapeutics domain. Unless expressly stated, opinions in this message are those of the individual sender and not of Astex Therapeutics Ltd. The recipient should check this email and any attachments for the presence of computer viruses. Astex Therapeutics Ltd accepts no liability for damage caused by any virus transmitted by this email. E-mail is susceptible to data corruption, interception, unauthorized amendment, and tampering, Astex Therapeutics Ltd only send and receive e-mails on the basis that the Company is not liable for any such alteration or any consequences thereof. Astex Therapeutics Ltd., Registered in England at 436 Cambridge Science Park, Cambridge CB4 0QA under number 3751674