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Public Lab Research note

Spectrometry UROP 5/5/11 update

by Alex-McCarthy | May 05, 2011 15:53 05 May 15:53 | #218 | #218

This week I spent some time working with the UV camera that was created last week. I realized that if I want to get an good adsorption dips in a transmission spectrum in the UV range I will not be able to use the black light LED because it is too low power, and its spectrum is limited to one peak (probably at 380 or 395 nm) I tried using the halogen lamp, with the UV pass, visible block filter, but it is very difficult to work with. For one, the intensity is so great that there is alot of glare- there would be no way to look at the spectrum of unfiltered halogen light and see the UV through the UV camera, as the UV spectrum would be completely outshone by the visible spectrum. When I put the UV pass/vis block filter over the spectrometer, there is no visible spectrum. the only explanation I can think of for this is that the UV spectrum is to faint to photograph. For some reason, the camera can see through the filter, meaning UV light (maybe also IR) is getting through the filter, but for whatever reason, the spectrometer cannot pick it up. I took a number of photos outdoors, with the filter over the camera, which worked very well as I suspected- indoor you cannot take photos, but outdoors the UV from the sun lights up everything. boston in UV more UV photos: here I also photographed the sun's spectrum, which was particularly easy to line up- this could make it a good light source. There was however alot of light pollution, but I was able to manage it. The heading photo shows a comparison of the photo I took with the actual spectrum of the sun. The one I took has some glare, which decreases the resolution.

I also made a short tutorial video for using the online software

and I updated the tool page for the PLOTS spectrometer

I'll be thinking of ways to capture that UV spectrum...


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