Hi Ramakrishna, There is no brief explanation other than saying "yes, you can". I am sure you have done the home work of google search and browsing through the standard text books -- but I am still attaching a presentation and some pointers below.

As in all TEM related "stuff" there are two parts of it i) collecting good diffraction pattern from a sample and ii) simulation and analysis of the data. Both needs some practice and lots of know hows (particularly if you are doing on "bad" samples). For the first part, best thing to do is to get hold of your machine manual and may be some tech rep from the company (or someone who has used the machine before for the same purpose), get a good sample and see how good diffraction pattern you can collect. As Eleonora points out, CBED is the way to go. SAD (selected area diffraction) works as well but CBED is newer, more accurate and cool way to go about it. If you have a thin crystalline sample (~10nm works great) that's not moving around under TEM you can get some very good point/ space group analysis done from CBED patterns. Most of the newer TEM / STEM machines come with "everything you need" to get good CBED patterns and is lot easier these days!! Plus there are ZOLZ, SOLZ and FOLZ patterns along with Kikuchi lines that will make life easier to get all crystallographic information from your sample.

For the second part, here are some excellent sites that are of great help:

Site from MSE department of University of Illinois at Urbana-Champaign:

http://emaps.mrl.uiuc.edu/emaps.asp

Commercial but great wealth of information in their application notes:

www.nanomegas.com

Loads of info from P. Stadelmann, CIME-EPFL,CH-1015 Lausanne and program JEMS

http://cimewww.epfl.ch/people/stadelmann/jemsWebSite/jems.html

Zaluzec's site at Argonne National Lab:

http://www.amc.anl.gov/

And http://www.public.asu.edu/~jspence/ElectrnDiffn.html that covers everything under TEM and Electron Diffraction (probably including this msg)!!

There are lots of free webtools available along with commercial software from Gatan and Olympus; don't forget to look up ImageJ plugins.

Attached is presentation that I downloaded from Internet sometime back, I do not know whether its still available but I am hoping the author wont mind this unauthorized distribution. There are some "brief" explanation there and loads of info on commercial software there.

Also for moments like this, get hold of a copy of "Transmission Electron Microscopy" by Williams and Carter from Springer!!

Cheers,

Palash

As far as I know, this can be achieved by looking at the fine structure of a convergent beam electron diffraction (CBED) pattern.

Hi Ramakrishna, There is no brief explanation other than saying "yes, you can". I am sure you have done the home work of google search and browsing through the standard text books -- but I am still attaching a presentation and some pointers below.

As in all TEM related "stuff" there are two parts of it i) collecting good diffraction pattern from a sample and ii) simulation and analysis of the data. Both needs some practice and lots of know hows (particularly if you are doing on "bad" samples). For the first part, best thing to do is to get hold of your machine manual and may be some tech rep from the company (or someone who has used the machine before for the same purpose), get a good sample and see how good diffraction pattern you can collect. As Eleonora points out, CBED is the way to go. SAD (selected area diffraction) works as well but CBED is newer, more accurate and cool way to go about it. If you have a thin crystalline sample (~10nm works great) that's not moving around under TEM you can get some very good point/ space group analysis done from CBED patterns. Most of the newer TEM / STEM machines come with "everything you need" to get good CBED patterns and is lot easier these days!! Plus there are ZOLZ, SOLZ and FOLZ patterns along with Kikuchi lines that will make life easier to get all crystallographic information from your sample.

For the second part, here are some excellent sites that are of great help:

Site from MSE department of University of Illinois at Urbana-Champaign:

http://emaps.mrl.uiuc.edu/emaps.asp

Commercial but great wealth of information in their application notes:

www.nanomegas.com

Loads of info from P. Stadelmann, CIME-EPFL,CH-1015 Lausanne and program JEMS

http://cimewww.epfl.ch/people/stadelmann/jemsWebSite/jems.html

Zaluzec's site at Argonne National Lab:

http://www.amc.anl.gov/

And http://www.public.asu.edu/~jspence/ElectrnDiffn.html that covers everything under TEM and Electron Diffraction (probably including this msg)!!

There are lots of free webtools available along with commercial software from Gatan and Olympus; don't forget to look up ImageJ plugins.

Attached is presentation that I downloaded from Internet sometime back, I do not know whether its still available but I am hoping the author wont mind this unauthorized distribution. There are some "brief" explanation there and loads of info on commercial software there.

Also for moments like this, get hold of a copy of "Transmission Electron Microscopy" by Williams and Carter from Springer!!

Cheers,

Palash

Read articles of Jean Paul Morniroli. These articles contain the answer to your question. For t[ample- http://dx.doi.org/10.1016/0304-3991(92)90511-H

Thanks Vladimir for posting that one -- Also Morniroli has a software and loads of info in his website http://www.electron-diffraction.fr/