Re: diode array detector

Shelley Diamond wrote:

> Has anyone heard of hanging a diode array detector in a pmt  
> position so as
> to detect any wavelength?  I have a group of people here who want to
> analyze mutations in bacteria on a single cell basis	and collect  
> emission
> spectra.  Any clues?	I once heard that Los Alamos people were  
> looking at
> these kinds of detectors.  Is there any reason that they wouldn't  
> work for
> this kind of detection??

Diode array detectors will only work for strong fluorescence signals,  
which you won't be getting from bacteria. A multianode PMT might  
work, depending on what the fluorescence comes from and how strong it  
is. When Anne Fu was a graduate student at CalTech with Steve Quake,  
she built a microfluidic sorter that discriminated between wild type  
and mutant GFP fluorescence in bacteria, but she just used two PMTs.  
She couldn't analyze or sort more than a couple of hundred bugs per  
second, and, to do that in a slow flow system, she needed 10^9 cells/ 
mL. Doing a multipoint spectrum on bacteria is going to be tough,  
even in a slow flow system with a multianode PMT.

-Howard