<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<TITLE>RE: Why FEG?</TITLE>
<META content="MSHTML 6.00.2800.1170" name=GENERATOR></HEAD>
<BODY>
<DIV dir=ltr align=left><SPAN class=789024216-23042004><FONT face=Arial
color=#0000ff size=2>Some people would kill for 1 additional angstrom...
:)</FONT></SPAN><SPAN class=789024216-23042004><FONT face=Arial color=#0000ff
size=2></FONT></SPAN></DIV><BR>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> Philip Koeck
[mailto:Philip.Koeck@biosci.ki.se] <BR><B>Sent:</B> Friday, April 23, 2004
7:09 AM<BR><B>To:</B> 'Lucken, Uwe'; 3dem@ucsd.edu;
microscopy@sparc5.microscopy.com<BR><B>Cc:</B> Sidorov, Max<BR><B>Subject:</B>
RE: Why FEG?<BR></FONT><BR></DIV>
<DIV></DIV><!-- Converted from text/rtf format -->
<P align=left><SPAN lang=en-us><FONT face="Courier New"
size=2>Hi,</FONT></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face="Courier New" size=2>From your plots
it seems that you need a FEG to reach resolutions beyond about 3
A,</FONT></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face="Courier New" size=2>But I can't see
any great advantage up to about 5 A resolution.</FONT></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face="Courier New" size=2>Is that
correct? (and what is all the excitement about then?)</FONT></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face="Courier New"
size=2>Philip</FONT></SPAN></P><BR>
<UL>
<UL>
<P align=left><SPAN lang=en-us><FONT face=Tahoma size=2>-----Original
Message-----<BR></FONT></SPAN><SPAN lang=en-us><B></B></SPAN><SPAN
lang=en-us><B><FONT face=Tahoma size=2>From:</FONT></B></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us><FONT face=Tahoma size=2> Lucken, Uwe
[<A
href="mailto:uwl@nl.feico.com">mailto:uwl@nl.feico.com</A>]<BR></FONT></SPAN><SPAN
lang=en-us><B></B></SPAN><SPAN lang=en-us><B><FONT face=Tahoma
size=2>Sent:</FONT></B></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us><FONT face=Tahoma size=2> 23 April 2004
15:03<BR></FONT></SPAN><SPAN lang=en-us><B></B></SPAN><SPAN
lang=en-us><B><FONT face=Tahoma size=2>To:</FONT></B></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us><FONT face=Tahoma size=2> Philip Koeck;
3dem@ucsd.edu; microscopy@sparc5.microscopy.com<BR></FONT></SPAN><SPAN
lang=en-us><B></B></SPAN><SPAN lang=en-us><B><FONT face=Tahoma
size=2>Cc:</FONT></B></SPAN><SPAN lang=en-us></SPAN><SPAN lang=en-us><FONT
face=Tahoma size=2> Max.Sidorov@Amd.Com<BR></FONT></SPAN><SPAN
lang=en-us><B></B></SPAN><SPAN lang=en-us><B><FONT face=Tahoma
size=2>Subject:</FONT></B></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us><FONT face=Tahoma size=2> RE: Why FEG?</FONT></SPAN><SPAN
lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000080 size=2>Dear
Philip, for an FEG one can set 0.6eV energy spread and for and Lab6 one
usually has 1.5eV energy spread. As you can see for -2000nm defocus and
61kx. There is a small mistake in the estimate of the convergence angle.
The parallel beam conditions are C2 diameter/7 in microprobe and I have
included the plots.</FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us></SPAN><SPAN lang=en-us><FONT
face=Arial color=#000080 size=2></FONT></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us> </SPAN></P>
<P align=left><SPAN lang=en-us><FONT color=#000080>end</FONT></SPAN><SPAN
lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT color=#000080>Sincerely
yours,</FONT></SPAN><SPAN lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT color=#000080>Dr. Uwe
Lücken</FONT></SPAN><SPAN lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT color=#000080>Senior Scientist
Application Development</FONT></SPAN><SPAN lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT color=#000080>FEI-Electron Optics;
Building AAE</FONT></SPAN><SPAN lang=en-us></SPAN></P>
<P align=left><SPAN lang=nl><FONT color=#000080>Achtseweeg Noord; 5600 MD
Eindhoven</FONT></SPAN><SPAN lang=en-us></SPAN><SPAN lang=nl></SPAN></P>
<P align=left><SPAN lang=en-us><FONT color=#000080>The
Netherlands</FONT></SPAN><SPAN lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT color=#000080>tel.:+31-40-2766106;
fax:+31-40-2766102</FONT></SPAN><SPAN lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT color=#000080>mob: +31 40
2791621</FONT></SPAN><SPAN lang=en-us></SPAN></P>
<UL>
<UL>
<P align=left><SPAN lang=en-us><FONT face=Tahoma color=#000000
size=2>-----Original Message-----<BR></FONT></SPAN><SPAN
lang=en-us><B></B></SPAN><SPAN lang=en-us><B><FONT face=Tahoma
color=#000000 size=2>From:</FONT></B></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us><FONT face=Tahoma color=#000000
size=2> Philip Koeck [<A
href="mailto:Philip.Koeck@biosci.ki.se">mailto:Philip.Koeck@biosci.ki.se</A>]<BR></FONT></SPAN><SPAN
lang=en-us><B></B></SPAN><SPAN lang=en-us><B><FONT face=Tahoma
color=#000000 size=2>Sent:</FONT></B></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us><FONT face=Tahoma color=#000000
size=2> Friday, April 23, 2004 10:44 AM<BR></FONT></SPAN><SPAN
lang=en-us><B></B></SPAN><SPAN lang=en-us><B><FONT face=Tahoma
color=#000000 size=2>To:</FONT></B></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us><FONT face=Tahoma color=#000000
size=2> 3dem@ucsd.edu;
microscopy@sparc5.microscopy.com<BR></FONT></SPAN><SPAN
lang=en-us><B></B></SPAN><SPAN lang=en-us><B><FONT face=Tahoma
color=#000000 size=2>Cc:</FONT></B></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us><FONT face=Tahoma color=#000000
size=2> Max.Sidorov@Amd.Com; Lucken, Uwe<BR></FONT></SPAN><SPAN
lang=en-us><B></B></SPAN><SPAN lang=en-us><B><FONT face=Tahoma
color=#000000 size=2>Subject:</FONT></B></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us><FONT face=Tahoma color=#000000
size=2> Why FEG?</FONT></SPAN><SPAN lang=en-us></SPAN></P>
<P align=left><SPAN lang=sv><FONT face=Arial color=#000000
size=2>Hi,</FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=sv></SPAN></P>
<P align=left><SPAN lang=sv><FONT face=Arial color=#000000
size=2></FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=sv></SPAN> </P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2>I've been playing around with Max Sidorow's CTFexplorer and I'm
finding it hard to see the<BR>advantage of FEG microscopes for
structural biology.</FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2>At 61000-times magnification I can't see any major difference
between the Tecnai 20T and<BR>the Tecnai F20T for
example.</FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2>Only at magnifications beyond 300000 is the F20T clearly
superior (due to better spatial<BR>coherence).</FONT></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2></FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN> </P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2>Am I (or is CTFexplorer) missing something
relevant?</FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2></FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN> </P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2>The CTFexplorer can be found at</FONT></SPAN><SPAN lang=en-us>
</SPAN><A href="http://clik.to/ctfexplorer"><SPAN
lang=en-us></SPAN><SPAN lang=en-us><U><FONT face=Arial color=#0000ff
size=2>http://clik.to/ctfexplorer</FONT></U></SPAN><SPAN
lang=en-us></SPAN></A><SPAN lang=en-us></SPAN><SPAN lang=en-us><FONT
face=Arial color=#000000 size=2>.</FONT></SPAN><SPAN
lang=en-us></SPAN><SPAN lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2>Upon request I can also send a Word file with the
CTF-plots.</FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2></FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN> </P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2>Philip</FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN></P>
<P align=left><SPAN lang=en-us><FONT face=Arial color=#000000
size=2></FONT></SPAN><SPAN lang=en-us></SPAN><SPAN
lang=en-us></SPAN> </P></UL></UL></UL></UL></BLOCKQUOTE></BODY></HTML>