Re: [PLOTS] Correlate detector values with absorption in a home-made spectrometer

[Liz Barry]

Hi There!

I'm sending this message over to the spectrometry list. 

Sincerely, 

Liz

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+1 336-269-1539

@lizbarry

On Wed, Aug 17, 2016 at 2:03 AM, shubhamrathore.iitr <shubhamra...@gmail.com> wrote:

Hi Everyone

I have made a CCD detector based spectrometer and am using tungsten lamp as source. I want to use it for absorption spectroscopy.

So I first take the source's spectrum (call it Yref) and then simply subtract it from sample spectrum, Ysam to get absorption spectrum (=Yref-Ysamp). To test my algorithm I did a test with transparent glass cuvette and it should show a flat line (equal absorption/reflection at all wavelenthts). Instead it shows the trend (shape of the curve) of the source spectrum only - though of reduced intensity.

Next I tried to use the division operator (y=Ysamp/Yref) and it too shows the similar problem -  trends of the source with diminished amplitude.

Can you please suggest what algorithms are mostly used for normalization of wavelengths (bringing all wavelengths intensities between 0-1 so that we can compare their relative intensities) and for getting absorption values from sample?

Attached are the two files - source spectrum and source spectrum with a transparent sheet in between.
Expected output should show a flat line for absorption by the sheet.

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[Jeffrey Warren]

Hi, I tried answering your question as posted on the site (in the new Question/Answer feature!): https://publiclab.org/questions/shubham/08-17-2016/how-to-neutralize-remove-the-source-s-spectra-to-obtain-absorption-spectra

Post to this group at plots-spectometry@googlegroups.com

 
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