Question –How and why does this occur?
The Leica system has at least three PMT’s that can do spectral
measurements. The Zeiss Meta system has one PMT capable of spectral
detection. They should all yield the same spectra from the same sample
(if working correctly).

Normally, a 5-or 10nm bandwidth will yield smooth curves with any PMT.
i.e. like the ones shown in the Chroma catalog, Chroma poster or any
other optical spectroscopic book

One PMT in our Leica system is yielded bumpy distributions with jagged
edges instead of normal smooth distributions that have a peak and a
trailing edge. This is different than the other two PMT’s in the same
system. Remember this is a 5nm bandwidth and not a 1nm bandwidth.  Has
any one else seen this on their confocal systems? The test substrate was
a  Chroma Fluorescent test slide but it  also occurs with almost all
samples that using this same PMT?

Question –How does this occur? Why is the spectra of one PMT different
that the other PMT’s in the same unit with the same sample.?  Has anyone
else seen this effect?
Just wondering about the quality of my data?  Wouldn't you!!!
Bob


Robert M. Zucker, PhD
U.S. Environmental Protection Agency
Office of Research and Development
National Health and Environmental Effects Research Laboratory
Reproductive Toxicology Division, MD 72
Research Triangle Park, North Carolina, 27711
Tel: 919-541-1585; fax 919-541-4017
e-mail: [log in to unmask]