Need advice, odd application

We are using a micro-channel plate followed by a phosphor screen to
get an image of very low energy (392 eV Carbon x-rays) x-rays focused
by an ellipsoidal x-ray mirror.  This produces a dim image that
reminded me of the Ring Nebula so I immediately thought of CCD amateur
astronomy.  We really need to capture this B&W image and somehow
integrate over time so we can measure less x-ray intensity.  I can
imagine integration times of maybe a few seconds.
We were advised of two possible paths, one cheap and one expensive.

Cheap
Get a web cam and use it for imaging and use shareware called Lispix
from NIST to do the integration (downloadable from the NIST site).

Expensive
Get an amateur astro CCD camera with Peltier cooler and do long
exposures (how long is long and how long is short?)

So...
What is the integration time of the human eye?
What is the integration time of a single CCD web cam image?
Will web cam integrated over several images give more apparent
brightness? (for focusing and aligning the x-ray mirror system, we
need to be able to see the image in near real time, maybe every few
seconds)
Do we need to simply integrate images or to do long exposures?

There seem to be lower cost amateur ccd astro cameras that might work
that do integration built in and more expensive ones that are cooled
that do long exposures.  I would rather spend the $279 on an
inexpensive amateur astro ccd cam than kluge together a web cam and
shareware.  I might even rahter spend over $650 for a cooled ccd cam
if it is what we really need.

Advice?

When this project is done, maybe I will bring it home and put it on my
8" scope.

David OHara
Parallax Research, Inc.
www.parallax-x-ray.com