Calibration

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Dave_VUB
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Re: Calibration

Post by Dave_VUB »

Here is a new measurement of acetone and the results on both Spinview and spectrum analyzer
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Luc
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Re: Calibration

Post by Luc »

It still looks a lot like fluorescence. The image is very clean in SpinView and your beam is well centered so optically speaking I don't see anything wrong.

Did you use the same test tube as for the previous sample? Fluorescent contamination tend to stick very well to glass.
Dave_VUB
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Re: Calibration

Post by Dave_VUB »

Hi, there is only one cuvette in use for my system. This is a macrocuvet in quarts as the original vials that are entered in the BOM are not found
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Luc
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Re: Calibration

Post by Luc »

I had the exact same problem when using a quartz cuvette in the past.

You can contact ChemLab Analytical, they bought Fiers a few years ago. If you give them the old reference they should be able to track it down for you.

Worst case, any test tube that has roughly 10mm OD should do the job. You may have to enlarge the hole to the proper diameter with a drill bit. Also, favor test tubes with the thinnest walls possible to avoid signal from the glass.
Dave_VUB
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Re: Calibration

Post by Dave_VUB »

I am in contact with the company in order to find the right fit or a similar product to use.

Could there be any explanation as to why the quarts glass is giving this result?
And could there be any problem with an open cuvet holder as shown below?
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Luc
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Re: Calibration

Post by Luc »

Could you take an image from above the setup? Also, could you confirm that you are using a lens to focus the beam?

What happened to me is that I contaminated my cuvette with a fluorescent compound and after that it was dead, impossible to remove the adsorbed contamination :-/ with the test tube when it happens I just replace the tube which cost only ~0.1€ or so.
Dave_VUB
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Re: Calibration

Post by Dave_VUB »

The setup is as the instructions said, just the holder for the cuvet is different as I had a different cuvet. There is no light-covering enclosure around the cuvet. The source light is never reflected back towards the lenses, it just goes through the sample
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Luc
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Re: Calibration

Post by Luc »

On the picture I don't see any focusing lens in front of the sample. Could you confirm if I spotted right?

You'll need one or you won't get any signal for sure. I used a 19mm achromat but a microscopy objective can do the job as well.
Dave_VUB
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Re: Calibration

Post by Dave_VUB »

I was not aware that another lens in front of the sample was needed. Could you point me to where this is mentioned?
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Luc
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Re: Calibration

Post by Luc »

They are in the cuvette assemblies themselves; the cuvette for test tubes even has a cylindrical lens to get a tighter spot size : https://www.thepulsar.be/article/raman-cuvette-upgrade/

The overall system is sketched here with a brief explanation: https://www.thepulsar.be/article/the-mo ... -openraman
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