Changeset 833 for trunk/doc/expgui5.html

Timestamp:

Dec 4, 2009 5:12:49 PM (13 years ago)

Author:

toby

Message:

# on 2005/02/09 21:47:28, toby did:
new feature: blank out shft & trans with zero use.

File:

• trunk/doc/expgui5.html (modified) (2 diffs, 3 props)

trunk/doc/expgui5.html

@@ -54 +54 @@
 <img SRC="5a.gif" align=TEXTTOP alt="EXPGUI Screen snapshot">
 <DL><DL>
-
-<P>
+<P><I>
+EXPGUI disables the refinement flags for profile terms 
+</I>trns<I> or </I>shft<I> 
+when the histogram zero point correction is refined.
+Neophyte users of GSAS sometimes incorrectly attempt to 
+refine these terms together, which almost always causes problems. 
+(Note that histogram 
+</I>Zero<I> is refined for parallel beam diffraction instruments, 
+typically synchrotron or neutron diffractometers, while 
+</I>trns<I> and </I>shft<I> are
+appropriate only for Bragg-Brentano geometry [typically lab x-ray] instruments.
+In the Bragg-Brentano case, </I>shft<I> 
+is related to the displacement of the 
+sample from the scattering plane, which is usually subject to error and thus 
+should be refined and </I>trns<I> is a correction for sample transparency, 
+which is typically refined only with a low density sample.)
+</I><P>
 If 
 <A href="expgui.html#multiplehistogram">
@@ -62 +77 @@
 profile values and settings can be collectively
 modified for groups of histograms and the pane appears slightly 
-differently
+differently, as is seen below:
 </DL></DL>
 <img SRC="5c.gif" align=TEXTTOP alt="EXPGUI Screen snapshot">