Hi Annette, I do not have any experience with the particular set up you are using, but just from general considerations, how about:
1. If you have control over humidity in the room, reduce it as much as you can during "icy" data collections 2. In another e-mail you mentioned you use copper pins. Try the steel ones which are thinner and thus will lead to less turbulence in the nitrogen flow. 3. Observe which side of the gas flow suffers from turbulence, and misalign the the cryo nozzle slightly such that the turbulence will be avoided, or at least reduced. 4. Increase the flow rate of the the nitrogen gas. 5. bring the nozzle as close to the sample as you can, while making sure that it does not shadow the diffraction image and does not lead to any possible collisions. 6. I wonder what will happen if you start data collection in those tricky orientations. Is it possible that you will have enough time to collect and get out of that configuration before too much ice builds up? 7. Does ice grow in the sample or on the pin, subsequently obstructing the sample? If the latter, can you pause data collection from time to time and remove the ice growth? Good luck! Nukri Ruslan Sanishvili (Nukri), Ph.D. Macromolecular Crystallographer GM/CA@APS X-ray Science Division, ANL 9700 S. Cass Ave. Lemont, IL 60439 Tel: (630)252-0665 Fax: (630)252-0667 rsanishv...@anl.gov ________________________________ From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> on behalf of Annette Herta Erbse <annette.er...@colorado.edu> Sent: Wednesday, September 13, 2017 2:54 PM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] ice build up during collection using 4 axis goniometer Dear All, We have a Rigaku XtalLab with a MM003 generator, a 4 axis goniometer and an Oxford 700 cryostream. I have been running into the problem that if I make full use of the 4 axis goniometer in the collection strategy I run into geometries where the angles between the pin/Xtal and the Oxford cryo head nozzle are smaller than 90 0 and in these positions I start collecting a lot of ice to a point were it get's blown off by the cold stream and I have lost Xtals. I was wondering if others have experienced the same and if there is a good way to avoid it. At the moment I feel like I simply have to avoid these ranges which is a shame since it restricts the data collection strategy. I appreciate any advice - Annette
