I would respectfully suggest that higher pixel resolution does not generally help much in these situations. If an average spot is 10 or more pixels wide then the profile is defined pretty well. But if the spots overlap, they still overlap with higher pixel density. It may make profile fitting more accurate, allowing more accurate "deconvolution" of the compound spot into its components, but it will not improve the overlap. Smaller or better-focused (on the detector, not the crystal?) beam, and longer camera length can help. It is analogous to chromatography- If two peaks coming off the column overlap, collecting smaller fractions will not help to resolve them. It may allow a better-informed decision on the cut-off points when you pool the fractions, but it won't separate the overlap. On the other hand a multi-circle goniometer is very useful. I remember in one of our last trips at SSRL (2007-8?) we used a (Huber 4-circle?) and it was very easy to have the long axis in the plane of the image throughout the rotation. In the absence of such you can resort to carefully bending the loop or bending the pin (Jim Holton made a nifty device for bending the pin) while keeping the xtal bathed in the cold stream.
On 08/19/2019 11:12 AM, graeme.win...@diamond.ac.uk wrote:
Chandra What you are looking for here is a beamline with a detector with many pixels (so you can resolve the long axis) and a multi-axis goniometer - probably a SmarGon / kappa and an Eiger 16M would make a good combination for this. Searching on https://urldefense.proofpoint.com/v2/url?u=http-3A__biosync.sbkb.org_&d=DwIFAg&c=ogn2iPkgF7TkVSicOVBfKg&r=cFgyH4s-peZ6Pfyh0zB379rxK2XG5oHu7VblrALfYPA&m=VcmIp54F7yM1JdiEMdBdR0y7xinGb-nsn2-3LI_BHto&s=5VFyqMBHljO-AEcXr3-pqjF8xFyEejXetVFOxOXLp_Y&e= Should allow you to make up a short list Best wishes Graeme On 19 Aug 2019, at 16:08, Chandramohan Kattamuri <00001c5b7cb6c764-dmarc-requ...@jiscmail.ac.uk<mailto:00001c5b7cb6c764-dmarc-requ...@jiscmail.ac.uk>> wrote: Dear All We recently collected a data set at APS, Chicago with unit cell dimensions of 68.4; 68.4 and 991.6 A. Our diffraction data extends to 3A with the APS set up, however, the long axis has been problematic, resulting in streaking of the diffraction data and requires a very specific orientation of the crystal for usable diffraction. Can anyone recommend beamlines that can give us higher resolution, or a source with a better goniometer allowing for more angle manipulation after looping? Thank a lot Chandra K ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://urldefense.proofpoint.com/v2/url?u=https-3A__www.jiscmail.ac.uk_cgi-2Dbin_webadmin-3FSUBED1-3DCCP4BB-26A-3D1&d=DwIFAg&c=ogn2iPkgF7TkVSicOVBfKg&r=cFgyH4s-peZ6Pfyh0zB379rxK2XG5oHu7VblrALfYPA&m=VcmIp54F7yM1JdiEMdBdR0y7xinGb-nsn2-3LI_BHto&s=NIk481IQQfkQVGsehEs9ptANwtNDLPRMWSSzJRcFHUY&e=
######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
