Hi, Don - sounds like a fascinating use, and it's entirely new to me. I'll
answer some of these questions but especially as we're getting lots of
spectrometry questions, might I ask you to add your questions and the
answers to this page on the wiki:
http://publiclaboratory.org/wiki/spectrometer-faq
I'm thinking that as we answer initial questions we're sure to find newer
questions, and it'll be good to keep a running list of them. Also it's a
good way for newcomers to find an interesting question to try to answer...
Does this look like something the countertop spectrometer could handle?
> (sensing in the 600-1050nm range)
In terms of range, it will probably work -- we're still figuring out how to
get clean data from 800-1000 nm since it can overlap with the 2nd order
spectrum (there are a few mailing list conversations about this but the
best I've heard is that we should be able to trust the red channel as the
doubling will mostly occur in the blue channel). Whether the exposure
measurements are linear is a question we still have to investigate, and a
staged dilution series of samples has been suggested.
> Would it require a special IR LED backlight, or does a typical cfl,
> halogen, or flourescent already give off IR light?
Halogens and xenons, and actually incandescents, all give off plenty of IR.
> What's the optimal amount of liquid to shoot through? Or: how do I know
> whether to try shooting through milk vs. just positioning the spectrometer
> over a well-lit dish of milk?
The easy answer is that you should try to maximize for the dynamic range of
the sensor -- the reading should average around 50% exposure so you get
clean data for your maxes and mins. No channel should be "blown out" (and
Spectral Workbench now detects that and warns you). The hard answer is that
it may be difficult to get quantitative about how much light you're
actually using. Try to use little enough light that you aren't blowing out
the sensor even with no sample, and little enough sample that you are still
getting enough light to get a good spectrum.
