Following the discussions of Spectral detection vs filter based 
detection, I have had some offline discussions and have come up with 
a few questions that I am hoping to hear discussed.

	There are two types of "Spectral" imaging detectors:  One uses a 
prism or diffraction grating and variable width thin slit aperture  
to 
select the wavelengths that enter the PMT (Basically using the 
prism/grating and thin slit window to serve the role of the emission 
bandpass 
filter). The other "spectral" imaging is Multi-channel spectral 
imaging.  In 
which the single PMT is replaced with a detector "array".  The total 
range 
of wavelengths which are sent to the detector array and the specific 
range a wavelengths each channel collects is user determined.

		There are clear flexibility advantages to the spectral detectors vs 
the filter detectors.  And there are analytical / imaging advantages 
of the multi-channel detectors in having detailed information more 
specific as to which wavelengths the signal is in - limited by the 
wavelength resolution of the detector. ( And yes similar information 
can be gotten by "Scanning" the single channel spectral detector, but 
at the cost of time).  BUT other than cost - what is/are the 
disadvantages of the single channel spectral vs the multi-channel?

	There is a "Binning" of the wavelengths effect of the single channel 
detector which results in a stronger signal (which can be done 
essentially after the fact with the multi-channels).  Is there a 
actual signal detection difference between the single and multi-
channel detectors?  Is there more amplification noise in the 
"array's" vs the tube PMT's?  Is there some other factor which 
effects the signal detection?  Maintenance?  Calibration?  Lifetime?

	All  response are welcome - if you want to respond directly rather 
than to the list that is fine as well.

	Thank you!

Richard E. Edelmann, Ph.D.
Electron Microscopy Facility Director
364 Pearson Hall
Miami University, Oxford, OH 45056
Ph: 513.529.5712        Fax: 513.529.4243
E-mail: [log in to unmask]
http://www.emf.muohio.edu

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