Hi Annette, We did some studies way back when that profiled the temperature signature of a cryostream as a function of distance using an infrared camera ago (JSR 2007, 14, 109-115). The original study looked at beam heating from the X-ray beam but in the process we noticed that the stream can have an hourglass oscillating shape with distance being a key parameter (basically discovered by a new toy and playing in the lab). Close is good as Nukri suggests, but there may be other optimum distances based on your setup - just not too far. We did this almost a decade ago and for our sins never published the cryostream characterization. I can try and dig out the data but provide no promises and each setup could be unique. I'm sure your system is set up with the stream centered but sometimes eddies in a particular orientation can bring humid air onto the sample due to the flow profile. A small shift in distance can mitigate this (or make it much worse). Nukri's observations are excellent, for the last one I'd just add that if you can't resolve the problem a little liquid nitrogen can be used to remove the ice. There are many lab inspired hacks to do this effectively. I may be 'misremembering' but I think James Holton at the ALS had a wonderful design and I am sure there are others out there. Ours is a Falcon tube with a handle and a small hole but as the saying goes, don't try that at home.
Good luck, ice is the enemy, Eddie http://getacrystal.org Edward Snell Ph.D. President and CEO Hauptman-Woodward Medical Research Institute Assistant Prof. Department of Structural Biology, University at Buffalo 700 Ellicott Street, Buffalo, NY 14203-1102 hwi.buffalo.edu Phone: (716) 898 8631 Fax: (716) 898 8660 Skype: eddie.snell Email: esn...@hwi.buffalo.edu [cid:image003.png@01D32CB4.EE8B0520] Heisenberg was probably here! From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Sanishvili, Ruslan Sent: Wednesday, September 13, 2017 5:05 PM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] ice build up during collection using 4 axis goniometer 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<mailto:rsanishv...@anl.gov> ________________________________ From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK<mailto:CCP4BB@JISCMAIL.AC.UK>> on behalf of Annette Herta Erbse <annette.er...@colorado.edu<mailto:annette.er...@colorado.edu>> Sent: Wednesday, September 13, 2017 2:54 PM To: CCP4BB@JISCMAIL.AC.UK<mailto: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
