Yes Colin, of course you are right about the 20-30 micron flight path. I thought John's question was about micron-size beam, not the micron-size crystal. Reading it over, I saw my mistake. As for the micron-size crystals, manipulating those will be another fun task. Fortunately, tractor beams (which some call more prosaic name of optical tweezers) are now reality and they should help. Cheers, N.
Ruslan Sanishvili (Nukri), Ph.D. GM/CA-CAT Biosciences Division, ANL 9700 S. Cass Ave. Argonne, IL 60439 Tel: (630)252-0665 Fax: (630)252-0667 rsanishv...@anl.gov -----Original Message----- From: Nave, C (Colin) [mailto:colin.n...@diamond.ac.uk] Sent: Tuesday, April 21, 2009 4:44 PM To: Sanishvili, Ruslan; CCP4BB@JISCMAIL.AC.UK Subject: RE: [ccp4bb] How small is a microbeam? Hi Yes good data with a micron size beam but, in this case, the path length was 20- 30 micron. I presume one would like a complete data set rather than a single or a few processable images. If the latter, then in principle anything is possible provided background is minimised and a low dose approach is taken - as for single particle cryo electron microscopy. I presume how to do all this will be one of the issues to be discussed at the workshop (which I am looking forward to). Regards Colin -----Original Message----- From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of Sanishvili, Ruslan Sent: 21 April 2009 22:21 To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] How small is a microbeam? Hi Jon, You can indeed get data with 1 micron(ish) beam. See for example http://journals.iucr.org/d/issues/2008/02/00/wd5082/index.html Different question is whether there is any benefit in using micron size beam. It is subject of much work and discussion (e.g. http://www.nsls.bnl.gov/newsroom/events/workshops/2009/mx/) Regards, Nukri Ruslan Sanishvili (Nukri), Ph.D. GM/CA-CAT Biosciences Division, ANL 9700 S. Cass Ave. Argonne, IL 60439 Tel: (630)252-0665 Fax: (630)252-0667 rsanishv...@anl.gov -----Original Message----- From: Jon Wright [mailto:wri...@esrf.fr] Sent: Tuesday, April 21, 2009 3:36 PM To: Sanishvili, Ruslan Cc: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] How small is a microbeam? Sanishvili, Ruslan wrote: > .......... Reasons for discriminating > 5-10 micron beams (minibeam) from ca 1 micron (microbeam) might have > been not so much their size but what it involved to achieve these sizes. Might I ask - do you really get data from 1 micron protein crystals? The reduction in scattering power (==crystal volume) from 5x5x5 microns to 1x1x1 is 125 and so it seems to present a grand challenge. I had understood there to be a more fundamental size limit, coming from radiation damage, which is still several microns for typical proteins. Do you suggest that ~1 micron sized crystals are no longer exclusively in the domain of powder diffraction? Millions of crystals working together to increase the signal does help a lot for such tiny ones :-) Going back to the original question, with 'nano' instead of 'micro', the FDA has defined [1] a "100 nm size-range limit of nanotechnology". Name suggetions for 100nm - 999 nm are most welcome. Are they "submicron"? Cheers, Jon [1] http://www.fda.gov/nanotechnology/regulation.html This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail. Any opinions expressed within this e-mail are those of the individual and not necessarily of Diamond Light Source Ltd. Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments are free from viruses and we cannot accept liability for any damage which you may sustain as a result of software viruses which may be transmitted in or with the message. Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom
