Re: Nipkow Disk Pinholes question

Posted by Farid Jalali on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Nipkow-Disk-Pinholes-question-tp592789p592791.html

Search the CONFOCAL archive at http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal Hello Don,
I have an Olympus DSU on their IX81 frame. There are disks with different slit widths that technically correspond to a particular objective lens. I have not been able to get an answer from Olympus as to the thickness of the optical section one gets with a particular disk- I would have to likely determine this myself. In practical terms it takes about 5-10 minutes to change the disk, opening the housing, loosening the disk motor, changing disks etc. In practical terms I have not seen a marked difference in image quality or optical sectioning ability when using the disk that is meant for the 60X1.42NA with the 100X1.4NA or vice versa. I have not used the DSU with lower mag/ lower NA objectives as the disk does reduce the effective illumination quite dramatically.

The Olympus DSU has 4-5 different disks for different magnification objectives. The disk is an array of horizontal and vertical slits that when spinning at high speed (3000 rpm), generates thousands of 'virtual pinholes' to effectively optically section your sample. The disk image must be in focus and there is an adjustment for this, otherwise the optical sectioning goes to hell.

Two cents delivered.
Best Regards
Farid

On Thu, May 15, 2008 at 4:07 PM, Donald M. O'Malley <[hidden email]> wrote:

Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal

 Hi Folks,

I am wondering if the pinhole-aperture diameter in the Nipkow
disk can be changed in instances where one might wish to
open the aperture to trade away some z-resolution in
exchange for increased signal?  I imagine this could be done
by switching between disks with different sized pinholes, but
am not sure if this would be fast and easy enough such that
one could go "back and forth" during e.g. a physiological
experiment.  This seems an area where traditional point-
scanning confocals may have an advantage.

Also, are there different disks for different magnification
objectives?  Is the right disk automatically selected on
such instruments?

thanks for any info.

Don O'Malley
Northeastern University

--
Farid Jalali MSc
Senior Research Technician- Lab Manager
Applied Molecular Oncology/ Princess Margaret Hospital
Radiation Medicine Program/ STTARR Program
Toronto, Canada
416-946-4501 X4351 (Princess Margaret Hospital)
416-581-7754 STTARR at MaRS Building
416-581-7791 STTARR Microscopy Suite