Best CL imaging techniques

[Probeman]

Although obviously it will depend significantly on the sample, I'm wondering in general what beam conditions and imaging parameters will produce the most sensitive high resolution panchromatic CL images. For example I seem to see on both my Cameca SX100 and FEI Quanta SEM that slowing down the beam scan does reduce the pixel to pixel noise. But if the beam (or stage) scan is very slow, the intensity of the CL output seems to be reduced. 

I recently took some video images on my Sx1200 and the images were OK, but the slowest scan speed on the Cameca video system is speed 7, which depending the image size is roughly a 60 sec frame time.  That means the pixel dwell times were roughly 1 msec per pixel.

Switching to the mapping system I then ran some CL stage scans using 100 msec pixel dwell times and I was quite disappointed with the CL image quality. 

I can understand that as the scan speed is reduced, the sample (recently I've been looking at quartz with some geologists) will experience greater beam damage, but I also wonder if one can "saturate" the CL emission by keeping the outer electron shells excited with enough electron flux?

Does it make any sense that slower beam (or stage) scans will result in less CL output?  I'm also wondering what combination of beam conditions and imaging parameters do others use to get good quality panchromatic CL images?
john