Understanding Counts in Spectrometer

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SUMMARY

The discussion focuses on the use of the Ocean Optics USB4000 spectrometer and SpectraSuite software for measuring light in aquariums. The user is encountering confusion regarding the "counts" data output by the spectrometer, which includes negative values. These negative counts likely indicate background subtraction, suggesting potential calibration issues. The user seeks guidance on converting counts into optical units for better interpretation of the data.

PREREQUISITES
  • Understanding of spectrometry principles and data interpretation
  • Familiarity with Ocean Optics USB4000 spectrometer
  • Knowledge of SpectraSuite software functionalities
  • Basic concepts of data calibration and background subtraction
NEXT STEPS
  • Research calibration techniques for the Ocean Optics USB4000 spectrometer
  • Learn how to interpret spectrometer output data in optical units
  • Explore the use of Voxler software for data interpolation and visualization
  • Investigate common issues and troubleshooting methods for negative counts in spectrometry
USEFUL FOR

This discussion is beneficial for researchers, aquarium hobbyists, and professionals in optics or environmental science who are utilizing spectrometry for light measurement and analysis.

Fpmagnani
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Well, I'm not a physician so, maybe my doubt is a little fool. Well, I'm mapping the light emitted by some lamps in some aquariums. For that, I'using a spectrometer named Ocean Optics USB4000 and a software named SpectraSuite. My intention is to discover how much is the total light getting into the aquariums and haw is it distributed in the aquarium. After taking the measurements, i will interpolate the data in the software Voxler from goldensoftware.
Well, my problem is in the beginning of these processes: the data that the spectrometer take is given by counts in each kind of wave, like that:
Wave Counts
178,91 -30,32
179,13 -30,32
179,34 -30,32
179,56 -47,11
179,78 -52,23
180,00 25,59
180,21 -3,29
180,43 4,70
180,65 56,92
180,86 -16,19
181,08 4,13
181,30 6,32
181,51 10,22
181,73 13,86
181,95 18,10
182,17 22,35
182,38 22,55
182,60 23,71
182,82 24,45
183,03 21,25
183,25 23,55
183,47 23,24
183,68 25,75
183,90 26,41
184,12 26,91
184,34 26,41
184,55 29,11
184,77 29,52
184,99 30,15
185,20 31,23
185,42 31,96
185,64 31,48
(......)
880,40 239,06
880,57 228,80
880,74 222,27
880,91 213,25
881,07 207,39
881,24 199,64
881,41 191,34
881,58 185,91
881,74 182,21
881,91 176,63
882,08 170,85
882,25 165,77
882,42 163,48
882,58 161,57
882,75 159,43
882,92 158,30
883,09 158,19
883,25 156,41
883,42 155,53
883,59 154,07
883,76 150,13
883,92 149,86
884,09 150,75
884,26 147,37
884,43 148,47
884,60 147,10
884,76 147,05
884,93 147,07
885,10 145,44
885,27 145,20
885,43 144,78
885,60 145,16
885,77 143,63
885,93 142,32
886,10 142,19
886,27 143,42
886,44 142,82
886,60 142,32
886,77 143,33
886,94 143,85
887,11 142,79
887,27 146,86
887,44 148,05
887,61 148,53
887,77 153,58
887,94 157,17
888,11 145,19
888,28 145,60
888,44 154,82
888,61 164,44
888,78 136,79
888,94 203,56
889,11 196,60
889,28 169,77
889,45 229,98
889,61 215,23

As you can see, there are even negative counts and I'm not getting really well what is the meaning of these "counts" and how can i convert it to any optic unites.
 
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That is something the manual should show. There should be some conversion factor between counts and some more useful unit.

Negative values suggest the device subtracts some background, if the result is negative some calibration might have gone wrong.