Dear Mark, <div>on several instruments I had laser duration of 0.6 deg would be too long and would result in completely saturated interference image. </div><div>0.1 or 0.2 were usual settings in my case. </div><div><br></div>
<div>The cell width is about 2 deg. If the pulse width is comparable to this width, any small error in the timing would result in hitting the side of the cell. </div><div>Please correct me if I am wrong. </div><div>best regards, Dmitry<br>
<br><div class="gmail_quote">On Thu, Feb 24, 2011 at 2:50 PM, Mark Agacan <span dir="ltr"><<a href="mailto:M.Agacan@dundee.ac.uk">M.Agacan@dundee.ac.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div style="margin:4px 4px 1px;font:10pt Tahoma">
<div>I checked the laser settings as advised and found:</div>
<div> </div>
<div> </div>
<table cols="4" border="1">
<tbody>
<tr>
<td width="50"><br>cell</td>
<td width="50"><br>laser delay</td>
<td width="50"><br>laser duration</td>
<td width="50"><br>exposure time</td></tr>
<tr>
<td width="50">2</td>
<td width="50">157.1 deg<br></td>
<td width="50"><br>1.7 deg</td>
<td width="50">6.30 uS<br></td></tr>
<tr>
<td width="50">
<div>4<br></div></td>
<td width="50">67.1 deg<br></td>
<td width="50">0.6 deg<br></td>
<td width="50">2.22 uS<br></td></tr>
<tr>
<td width="50">6<br></td>
<td width="50">337.6 deg<br></td>
<td width="50">1.7 deg<br></td>
<td width="50">6.3 uS<br></td></tr></tbody></table>
<div> </div>
<div>I also found this in the rasmb archives:</div>
<div> </div>
<div>"<span style="word-spacing:0px;font:medium 'Times New Roman';text-transform:none;color:rgb(0,0,0);text-indent:0px;white-space:normal;letter-spacing:normal;border-collapse:separate">The main "gotcha" about setting the duration is that if you go too high you<br>
will end up with the superposition of a single-slit interference pattern upon the<br>double-slit interference pattern. As long as you use the typical <strong>0.5 - 0.8<br>degrees for the duration</strong> (assuming that you are NOT using the old style interference<br>
window holders) you will be fine."</span></div>
<div><span style="word-spacing:0px;font:medium 'Times New Roman';text-transform:none;color:rgb(0,0,0);text-indent:0px;white-space:normal;letter-spacing:normal;border-collapse:separate"></span> </div>
<div><span style="word-spacing:0px;font:medium 'Times New Roman';text-transform:none;color:rgb(0,0,0);text-indent:0px;white-space:normal;letter-spacing:normal;border-collapse:separate"><font face="Tahoma" size="2">So I'm thinking to bring the laser duration for cell2 and cell6 down to the value of cell4. Any further advice is greatly appreciated.</font></span></div>
<div><span style="word-spacing:0px;font:medium 'Times New Roman';text-transform:none;color:rgb(0,0,0);text-indent:0px;white-space:normal;letter-spacing:normal;border-collapse:separate"><font face="Tahoma" size="2"></font></span> </div>
<div><span style="word-spacing:0px;font:medium 'Times New Roman';text-transform:none;color:rgb(0,0,0);text-indent:0px;white-space:normal;letter-spacing:normal;border-collapse:separate"><font face="Tahoma" size="2">Many Thanks,</font></span></div>
<div><span style="word-spacing:0px;font:medium 'Times New Roman';text-transform:none;color:rgb(0,0,0);text-indent:0px;white-space:normal;letter-spacing:normal;border-collapse:separate"><font face="Tahoma" size="2"></font></span> </div>
<div><span style="word-spacing:0px;font:medium 'Times New Roman';text-transform:none;color:rgb(0,0,0);text-indent:0px;white-space:normal;letter-spacing:normal;border-collapse:separate"><font face="Tahoma" size="2">Mark</font></span></div>
<div><span style="word-spacing:0px;font:medium 'Times New Roman';text-transform:none;color:rgb(0,0,0);text-indent:0px;white-space:normal;letter-spacing:normal;border-collapse:separate"><font face="Tahoma" size="2"></font></span> </div>
<div> </div>
<div> </div>
<div> </div>
<div>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br>Dr Mark Agacan, Scientific Officer for the Division of Biological Chemistry and Drug Discovery,<br>Wellcome Trust Biocentre, College of Life Sciences, University of Dundee, Dundee, DD1 5EH <br>
Tel: +44 1382 386095 Fax: +44 1382 345764 Mobile: 07525 451 117<br>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</div>
<div> </div>
<div>
<div>************************************************************ </div>
<div>
<div><font color="#666666">Please consider the environment. Do you really need to print this email?</font> </div></div><br><br>>>> Tom Laue <<a href="mailto:Tom.Laue@unh.edu" target="_blank">Tom.Laue@unh.edu</a>> 2/24/2011 13:05 >>><br>
Hi Mark-<br>The interference system requires the use of sapphire windows, except at <br>very low rotor speeds.<br>Modern synthetic sapphire windows may be used to 230 nm. The old <br>sapphire windows were not clear much past 280 nm, but that is no longer <br>
an issue.<br>I know that some labs have switched to using only sapphire window since <br>they almost never break, and may be used with all three optical systems.<br>Best wishes,<br>Tom<br><br>On 2/24/2011 4:37 AM, Mark Agacan wrote:<br>
> Hello,<div class="im"><br>> I have attached a jpeg image showing recent SV interference data plots <br>> taken from sedfit.<br>> All data was collected with quartz windows as I was primarily <br>> interested in the absorbance @ 280 nm signal.<br>
> IP2 and IP6 are very noisy but IP4 looks fine.<br>> Is this a calibration problem or is this related to damaged windows / <br>> centerpieces (there are no visible defects or scratches on any of the <br>> components).<br>
> Many Thanks,<br>> Mark<br></div>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br>> Dr Mark Agacan, Scientific Officer for the Division of Biological <br>> Chemistry and Drug Discovery,<br>> Wellcome Trust Biocentre, College of Life Sciences, University of <br>
> Dundee, Dundee, DD1 5EH<br>> Tel: +44 1382 386095 Fax: +44 1382 345764 Mobile: 07525 451 117<br>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br>> ************************************************************<br>
> Please consider the environment. Do you really need to print this email?<br>><br>> The University of Dundee is a registered Scottish charity, No: SC015096<div class="im"><br>><br>><br>> _______________________________________________<br>
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<br></div>-- <br>Department of Biochemistry and Molecular Biology<br>University of New Hampshire<br>Durham, NH 03824-3544<br>Phone: 603-862-2459<br>FAX: 603-862-0031<br>E-mail: <a href="mailto:Tom.Laue@unh.edu" target="_blank">Tom.Laue@unh.edu</a><br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Dr. Dmitry Veprintsev<br>Biomolecular Research Laboratory, OFLC/103<br>Paul Scherrer Institut<br>5232 Villigen PSI<br>Switzerland<br>Tel +41 (0) 56 310 5246; Fax +41 (0)56 310 5288<br>
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