[RASMB] interference optics

[Walter Stafford]

I would like to add to this discussion that one can eliminate residual jitter to a large extent by using interference window folders in the top windows. A large part of the jitter is due to "breathing" of the optical bench - as Tom points out. But some is also due to jitter in the timing circuitry for the laser. By using the interference window holders you always mask off the same bits of "glass" even though there is some jitter in the timing of the pulse. Doing that cleans up the signal significantly. 

If you take care of jitter and integer fringe jumps in the preprocessor of SEDANAL, you can see the raw data quite nicely corrected for these artifacts before you do any fitting.
_________________________
Walter Stafford
wstafford3 at walterstafford.com



On Jan 15, 2013, at 12:41, Ute Curth wrote:

> Dear all,
> 
> I hope you had a good start in 2013 and some of you can possibly give me advice on a problem with our Xl-I machine. The raw data of  our interference optics show (and always showed) such an enormous vertical jitter that it is hard to judge whether the sample sediments at all and where the meniscus is located (see attached file). Whereas, after subtraction of TI and RI noise the data look quite nice, I am wondering what the reason of this jitter is. Has anyone an idea about its possible source and how I can get rid of it? 
> 
> Thank you in advance
> 
> Ute
>  -- 
> PD Dr. rer. nat. Ute Curth
> > Medizinische Hochschule Hannover
> > Strukturanalyse
> > OE 8830
> > Carl-Neuberg-Str. 1
> > 30625 Hannover
> > Germany
> > 
> > Tel.: +49-511-5329372
> > Fax : +49-511-5325966
> <Interference_data.pdf>_______________________________________________
> RASMB mailing list
> RASMB at list.rasmb.org
> http://list.rasmb.org/listinfo.cgi/rasmb-rasmb.org

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.rasmb.org/pipermail/rasmb-rasmb.org/attachments/20130115/61e76e17/attachment.htm>