<html><head><base href="x-msg://22/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hello Genoveva,<div><br></div><div><br></div><div>Sorry for the delay in responding. </div><div><br></div><div>The way I understand surface imperfections, two effects are typically talked about:</div><div><br></div><div>Roughness - corresponding to microscopic de-placement/misalignment of surface atoms. As far as I understand, this will effectively correspond a change in the slope of the reflectivity-curve, modeled by the alpha-parameter of the guide components. </div><div><br></div><div>Wavyness - longer length-scale surface effects arising from manufacturing of the mirrors, typically variation that occurs in the cm-m range. Both the Guide_wavy and Guide_gravity components implement a phenomenological description of this effect by emitting outgoing neutrons within a gaussian 'cone'. I think Kaspar Klenų from University of Copenhagen has worked a bit at wavyness lately, putting him cc: so that you can contact him directly if interested?</div><div><br></div><div><br></div><div>Best regards,</div><div><br></div><div>Peter Willendrup</div><div><br></div><div><div><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>--<br>-------------------------------------------------------------------<br>Peter Willendrup - Development engineer<br><br>RISŲ DTU<br>Materials Research Division<br>Frederiksborgvej 399<br>DK-4000 Roskilde<br><br>Tlf.: (+45) 4677 5862<br>Mobil.: (+45) 2125 4612</div><div>Fax.: (+45) 4766 5758</div><div>Email: <a href="mailto:pkwi@risoe.dtu.dk">pkwi@risoe.dtu.dk</a></div><div>-------------------------------------------------------------------<br></div><div><br></div></div></span></div></span></div></span></span></div></div><div><br><div><div>On 20/01/2011, at 13.11, Genoveva Burca wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div marginleft="10" marginright="10" margintop="10" marginbottom="10" style="margin-left: 10px; margin-right: 10px; margin-top: 10px; margin-bottom: 10px; "><div align="left" style="text-align: left; "><font face="Arial" size="+0" color="#000000" style="font-family: Arial; font-size: 10pt; color: rgb(0, 0, 0); "><b><a href="mailto:mcstas-users@mcstas.org">mcstas-users@mcstas.org</a> writes:</b></font></div><div align="left" style="text-align: left; "><span style="background-color: rgb(208, 208, 208); "><font face="Arial Unicode MS" size="+0" color="#000000" style="font-family: 'Arial Unicode MS'; font-size: 10pt; color: rgb(0, 0, 0); ">Can you provide a little more information.</font></span></div><br><div align="left" style="text-align: left; "><span style="background-color: rgb(208, 208, 208); "><font face="Arial Unicode MS" size="+0" color="#000000" style="font-family: 'Arial Unicode MS'; font-size: 10pt; color: rgb(0, 0, 0); ">What sort of super mirror arrangement are you trying to model?</font></span></div><br><div align="left" style="text-align: left; "><span style="background-color: rgb(208, 208, 208); "><font face="Arial Unicode MS" size="+0" color="#000000" style="font-family: 'Arial Unicode MS'; font-size: 10pt; color: rgb(0, 0, 0); ">Are you interested in the performance of a long guide system or a smaller device such as a polariser?</font></span></div><br><div align="left" style="text-align: left; "><span style="background-color: rgb(208, 208, 208); "><font face="Arial Unicode MS" size="+0" color="#000000" style="font-family: 'Arial Unicode MS'; font-size: 10pt; color: rgb(0, 0, 0); ">Best regards</font></span></div><br><div align="left" style="text-align: left; "><span style="background-color: rgb(208, 208, 208); "><font face="Arial Unicode MS" size="+0" color="#000000" style="font-family: 'Arial Unicode MS'; font-size: 10pt; color: rgb(0, 0, 0); ">Robert</font></span></div><br><br><br><div align="left" style="text-align: left; "><font face="Arial" size="+0" color="#000000" style="font-family: Arial; font-size: 10pt; color: rgb(0, 0, 0); ">Hi Robert,</font></div><br><div align="left" style="text-align: left; "><font face="Arial" size="+0" color="#000000" style="font-family: Arial; font-size: 10pt; color: rgb(0, 0, 0); ">Thank you very much for your reply.</font></div><br><div align="left" style="text-align: left; "><font face="Arial" size="+0" color="#000000" style="font-family: Arial; font-size: 10pt; color: rgb(0, 0, 0); ">I'm interested in the performance of a long guide system (my project includes modelling the passage of neutrons along supermirror guides.)</font></div><br><div align="left" style="text-align: left; "><font face="Arial" size="+0" color="#000000" style="font-family: Arial; font-size: 10pt; color: rgb(0, 0, 0); ">Best wishes,</font></div><br><div align="left" style="text-align: left; "><font face="Arial" size="+0" color="#000000" style="font-family: Arial; font-size: 10pt; color: rgb(0, 0, 0); ">Genoveva</font></div><br><font face="monospace"><br>--<span class="Apple-converted-space"> </span><br>The Open University is incorporated by Royal Charter (RC 000391), an exempt charity in England & Wales and a charity registered in Scotland (SC 038302).</font><span class="Apple-converted-space"> </span>_______________________________________________<br>mcstas-users mailing list<br><a href="mailto:mcstas-users@mcstas.org">mcstas-users@mcstas.org</a><br><a href="http://mailman.mcstas.org/cgi-bin/mailman/listinfo/mcstas-users">http://mailman.mcstas.org/cgi-bin/mailman/listinfo/mcstas-users</a><br></div></span></blockquote></div><br><div>
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