Electronics > Beginners
Measuring light spectrum intensity
ker2x:
Excuse me but... aren't you simply trying to build an optical spectrometer here ?
https://en.wikipedia.org/wiki/Optical_spectrometer
a grating plate (or a prism, pretty much the same thing) and a camera ?
You will have a problem with UV and IR and anything out of the humanly visible spectrum however.
You can buy astronomy camera (with IR/UV filter) but they tend to buy expensive because it's a niche market. And if you add an IR bandpass filter you'll end up with very VERY low sampling rate. (1hz or even less)
edpalmer42:
I'm surprised nobody has mentioned https://spectralworkbench.org/ . Depending on the level of precision required, any old DVD and a webcam plus an hour or two of work might be all you need.
Ed
jbeng:
As far as PMTs go, it is rare to find inexpensive ones.
I previously worked for a company which built machines for medical research called flow cytometers (cell-sorting machines), which relied on PMTs for detection of the very weak high-speed optical signals. The ones we used (mfg.= Hamamatsu) were modules which had thier own integral HV power supplies running on 15vdc and had an input for gain control. IIRC they were approx. 1200 USD each.
scatterandfocus:
It seems that there are quite a few diy projects out there for spectrometers using cameras, but they all seem to drop off at the beginning of the UV spectrum.
donlisms:
If you want to experiment with photomultiplier tubes, an easy way to get started might be to pick up an old densitometer on an auction site. These were used a lot in darkroom work. I have some Macbeth photographic-oriented devices, mostly tube-based. They have gorgeous big mirrored panel meters, the power supply for the PM tube is already there, there's a log conversion circuit if you'd like to keep that. Assuming you get one that works or only needs a little attention, you can just start right in. I can't speak to the spectral response, but for photographic purposes, the goal was "flat through the visual spectrum," which was accomplished with three filters and some tuning. I have a vague recollection that there was an IR filter in the path, but that could be my imagination.
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