Depends on the geometry of the goniometer/pin relative to the X-ray beam. If the pin is too close, it will possibly cast a shadow. If the pin is aligned at a shallow angle relative to the X-ray source beam, the pin or the goniometer may get in the way regardless of how far away the crystal is from the pin. That it, there are certain kappa and omega angles where the pin is aligned along the beam that significantly block a portion of your imaging device. On 4 angle goniometers you have to carefully evaluate the kappa and omega ranges sampled to avoid pin shadows.
I would collect new data, as you will have lost a lot of data in the shadow area, and the pin shadow is variable depending on the omega angle. If you have crystals available, it would be worth collecting again properly. Roger Rowlett On Apr 27, 2017 5:18 PM, "Dr A.A. Jalan" <[email protected]> wrote: > Dear all, > > Thank you for the lighting fast responses! The data was acquired at the > DLS I03 beamline which I think uses a Kappa goniometer. I have attached > another image of the crystal. The crystal does appear to be very close the > pin but is it close enough to cast a shadow? > > Since the shadow moves, is there anyway to exclude this region during data > processing or should I reject this dataset and consider another one which > is somewhat lower resolution but without any shadowy artifacts. > > Thank you > > Abhishek > > > > -------- Original Message -------- > Subject: [ccp4bb] shadow at the edge > Date: 2017-04-27 21:49 > From: "Dr A.A. Jalan" <[email protected]> > To: [email protected] > > > > Dear all, > > The attached diffraction image has a shadow at the right edge. It moves > from the top to the bottom right corner. I was wondering if anyone knows > what it could be and whether it would affect data processing? > > Thank you > > Abhishek > > > > > > >
