[RASMB] interference optics

[Jeff Lary]

----- Original Message ----- 
From: <judithk at vax2.concordia.ca>
To: <rasmb at server1.bbri.org>
Sent: Wednesday, July 21, 2004 3:08 PM
Subject: [RASMB] interference optics


> I'm trying to learn how to set up our XLi for interference optics and I
> have several questions:
> 1)There is a main menu "interference" which includes "laser setup"; within
> that menu, one can set up the laser for each of the cells and for the
> scallop. Or, one can go to each cell, click on "details", then on "laser
> setup" and do the same setup. As far as I can tell, the setup you do in
> one menu does not show up in the other one. The question - which takes
> precedent and which one should be used? Do you have to enter the same
> settings in both?
>
Judith,

The settings that are currently in effect, via changing them through the
"Interference" menu route, are then used when you create a new scan file.
Typically what I do is to set up the interference parameters for all the
cells
using the |interference|laser setup| menu choice and then create a new scan
file.
Once you are collecting data the only settings that matter are those that
are contained in the active scan file.

> 2) What factors go into deciding on the laser duration? It is obvious that
> it affects the overall brightness of the fringe pattern; is there anything
> else to consider when setting the duration?
> Thanks for any advice you can give.

This one is a little harder to explain in a short amount of space because
there
are also important issues (at least I think they are important) with the
settings
for brightness and contrast.  I have a PDF file of a short presentation that
I made about this topic that can be viewed at
ftp://spin6.mcb.uconn.edu/pub/workshop2004/xli-setup.pdf .

The main "gotcha" about setting the duration is that if you go too high you
will
end up with the superposition of a single-slit interference pattern upon the
double-slit interference pattern.  As long as you use the typical 0.5 - 0.8
degrees
for the duration (assuming that you are NOT using the old style interference
window holders) you will be fine.

>
> Judith Kornblatt
> Dept of Chemistry and Biochemistry
> Concordia University
> 7141 Sherbrooke Ouest
> Montreal, Qc H4B 1R6
> Tel: 1 514 848 2424, ext 3384   FAX: 1 514 848 2868
>


Jeff Lary
Biotechnology Center Unit-3149
ph: 860-486-5036
fax: 860-486-5005
email: jeffrey.lary at uconn.edu
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