<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi everyone,<div><br></div><div><br></div><div>Forwarding the following information from Lucia Alianelli (Diamond, UK).</div><div><br></div><div>Regards,</div><div><br></div><div>Peter</div><div><br></div><div><br></div><div>-------------------------- From Luica: -------------------------------------</div><div><br></div><div>Hi Tom,<br><br>You can use the NOP package, an extension to XOP.<br>NOP contains a neutron cross-section database, and tools to calculate<br>and plot reflectivity from crystals, mirrors etc.<br><br>Regards,<br>Lucia<br><br><br><br><br><br><br>XOP2.1 webpage:<br><a href="http://www.esrf.eu/computing/scientific/xop2.1/intro.html">http://www.esrf.eu/computing/scientific/xop2.1/intro.html</a><br><br>Ftp:<br><a href="http://ftp.esrf.eu/pub/scisoft/xop2.1/">http://ftp.esrf.eu/pub/scisoft/xop2.1/</a><br><br><a href="http://ftp.esrf.eu/pub/scisoft/xop2.1/Windows/Extensions/">http://ftp.esrf.eu/pub/scisoft/xop2.1/Windows/Extensions/</a> <br><br><br><br><div><html>On Apr 20, 2008, at 5:33 PM, Peter Willendrup wrote:</html><br class="Apple-interchange-newline"><blockquote type="cite">Hello Tom,<br><br><br>On Apr 16, 2008, at 3:57 PM, wokaoyan1981 wrote:<br><blockquote type="cite">I'm visualizing the double bent crystal monochromator and here is my <br></blockquote><blockquote type="cite">problem:<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">What is the suggested value of r0(Maximum Reflectivity) and <br></blockquote><blockquote type="cite">t0(Transmission Efficiency) for each crystal plane of Si?(The <br></blockquote><blockquote type="cite">default is 0.7 and 1.0 respectively.) Or where should I manage to <br></blockquote><blockquote type="cite">obtain the reflectivity and transmision files for each Si(hkl)?<br></blockquote><br>I would suggest you to start out by for example some of these references<br><br>Sears et al Acta Cryst. (1997). A53, 35-45 Bragg Reflection in Mosaic <br>Crystals. I. General Solution of the Darwin Equations<br>Sears et al Acta Cryst. (1997). A53, 46-54 Bragg Reflection in Mosaic <br>Crystals. H. Neutron Monochromator Properties<br><br>Kimura et al NIMA 482 (2002) 799–805 Development of a horizontally and <br>vertically focused neutron<br>monochromator using stacked elastically bent Si single crystals<br><br>Or perhaps one of the other McStas users has one or more relevant <br>reflectivity profiles to contribute?<br><br><br>Regards,<br><br>Peter Willendrup<br><br><br><br>_______________________________________________<br>neutron-mc mailing list<br><a href="mailto:neutron-mc@risoe.dk">neutron-mc@risoe.dk</a><br>http://mailman.risoe.dk/mailman/listinfo/neutron-mc<br></blockquote></div><br></div></body></html>