<div>Hello Lucia,<br><br>Thank you very much for your reply! I understand the unexpected output <br>when you shed light on it.<br>Now I take an angular scan as you suggest, here is part of the result:<br>( Si 311, <br> TDS=0, <br> Debye Waller factor=-288,<br> Linear cell expasion=1, <br> Mosaic Crystal=No,<br> Geo=BRAGG diffr beam, <br> Scan type=Theta(absolute),<br> Energy/Wavelenghth unit=Wavelenggh(angstrom), <br> Angular Unit=Degrees, <br> Fixed value=1.2, <br> Min scan Value=20,<br> Max scan Value=25, <br> Scan Points=1000, <br> Asymetry angle=0, <br> Crystal thickness=0.6999)<br> ...<br> 21.4911 6.11795e-006<br> 21.4916 7.52919e-006<br> 21.4921 0.000120346<br> 21.4926 0.000303971<br> 21.4931 6.50051e-005<br> 21.4936 0.000526068<br> 21.4941 5.63596e-006<br> 21.4946 0.000368681<br> 21.4951 0.00645020<br> 21.4956 0.0147543<br> 21.4961 0.000430623<br> 21.4967 0.000171211<br> 21.4972 0.00121510<br> 21.4977 0.000588131<br> 21.4981 0.000492101<br> 21.4986 0.000255239<br> 21.4991 2.99586e-005<br> 21.4996 1.94318e-005<br> 21.5002 9.97257e-005<br> 21.5007 0.000119835<br> 21.5012 8.19391e-005<br> 21.5016 3.93121e-005<br> 21.5021 1.48155e-005<br></div><div> ...<br>And I see the Bragg peak near 21.5 degree.<br>My question is: Then how should I get reflectivity file from the data above?<font class="dict18">Integral or something else?</font> Actually, I don't clearly understand the reflectivity file required.<br><br>Yours sincerely,<br>Tom<br></div><div></div><br>在2008-04-25，"Alianelli L (Lucia)" <lucia.alianelli@diamond.ac.uk> 写道：<br> <blockquote id="isReplyContent" style="border-left: 1px solid rgb(204, 204, 204); margin: 0px 0px 0px 0.8ex; padding-left: 1ex;">
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2">Hi Tom,</font></span></div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2">it seems that the energy scan type is not optimised in NOP.
So I would suggest you look at angular scans, i.e. rocking
curves.</font></span></div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2">I attach the rocking curve for lambda = 0.04 nm. The Bragg
angle is about 7 degrees, not 21.5. At 21.5 deg you would find zero
intensity.</font></span></div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2">Of course you are going to get an error when trying lambda
= 0.7 nm or 7 Angstrom. The reason is that the Si 311 d-spacing is 1.64
Angstrom, so you cannot find any Si 311 Bragg reflection for such cold
neutrons!!!!</font></span></div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2">Also are you interested in perfect crystal reflectivity?
</font></span></div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2">Or reflectivity from a mosaic or bent crystal?
</font></span></div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2">Regards,</font></span></div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2">Lucia</font></span></div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2"></font></span> </div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2">If you want to look at theory, measurements and simulations
of neutron reflectivity from crystals, you can look at the bibliography in
my thesis:</font></span></div>
<div dir="ltr" align="left"><span class="444021812-25042008"><font color="#0000ff" face="Arial" size="2"><a href="http://www.esrf.eu/computing/scientific/people/srio/publications/alianelli_thesis.pdf">http://www.esrf.eu/computing/scientific/people/srio/publications/alianelli_thesis.pdf</a></font> </span></div>
<div dir="ltr" align="left"><span class="444021812-25042008"> </span></div><br>
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