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About 2 years ago, when I was building a 16-channel spectral detector for
our multiphoton microscope with the R5900U-xx-L16 linear PMT array as a
detector, I was told by Hammamatsu that for photon counting, I will be
better off using the original model with the standard bilalkali
photocathode, rather than using the newer super- or ultralakali models,
since the older model has much lower dark counts (and can be purchased as a
photon counting model R5900P-00-L16, tested for low-dark counts). 
The peak QE around 400 nm was OK for our purpose, since besides fluorescent
proteins, we are interested in second harmonics signal from collagen, which
on our system is between 350 and 400 nm.

I wonder if there is going to be a hybrid multi-anode PMT. 

Stan Vitha
Microscopy and Imaging Center
Texas A&M University
BSBW 119
College Station, TX 77843-2257

On Sat, 22 Jan 2011 16:24:44 -0600, James Pawley <[log in to unmask]> wrote:

>
>I echo Mark's cautions. There are long 
>discussions of these matters in Chapter 12 and 
>Appendix 3 of the Handbook. With respect to the 
>URL Mark sent out, ultra bialkali with a maximum 
>QE of about 43% looks very good BUT:
>
>1) It occurs at a wavelength of 350 nm, well into 
>the near UV where we really seldom have need for 
>a detector in confocal-type micrsocopy.
>
>
>Cheers,
>
>Jim Pawley