Ocean Optics Deuterium-Halogen Calibration Light Source - Manual (Page 15)

A: Calibration Basics
000-10000-191-02-201309 7
• JCGM100:2008: GUM 1995 with minor corrections
Ocean Optics calibrations are done in relation to these international standards.
Ocean Optics provides a calibration of the DH-3 plus-CAL on an absolute irradiance scale in
µW/nm/cm^2. The sources of uncertainties taken into account are listed below in the example. The actual
values are listed in the individual calibration certificate for your light source. The calibration certificate
contains more detailed information.
Sources of Uncertainties
Variable Source of uncertainty
1. R Uncertainty in reproducibility [R], caused by switching on/off
_1.1 S Stability[S] within 50 hours of operation
2. T and F
Influence of temperature [T] and humidity [F] in the air. The temperatures during
calibration have a temperature range of 19 °C to 25 °C. The humidity might
influence the calibration in the NIR for wavelength larger than 1100 nm.
3. d
Uncertainty in mounting distance [d] of the used cosine corrector. 1.8 % per
0.1 mm deviation from aperture plane.
4. ROT Uncertainty from rotating [ROT] the cosine corrector.
5. D_Lambda
Uncertainty caused by wavelength calibration of the spectrometer which was
used to calibrate the light source. [D_Lamba[QE]=0.3 nm,
D_Lambda[NirQ512]= 1 nm]
6. D_AbsIrrad
Uncertainty of the calibration light source used. This is in most cases the Ocean
Optics working standard. See calibration certificate for details.
7. StrayL
Influence from spectrometers’ internal stray light which was used to calibrate the
light source.
8. T_TEC_
Influence of the sensor temperature [TEC] of the spectrometer which was used
to calibrate the light source.
9. Dark
Influence from uncertainties of the measured dark level of the spectrometer
used to calibrate the light source.
10. Rep Reproducibility of the used spectrometer system for calibration.
11. SP_Lin
Linearity of the spectrometer system which was used to calibrate the light
source.
12. Bend Uncertainty caused by bending [Bend] of the fibers.
These factors are taken into account for deriving the wavelength for resolved levels of uncertainty (listed
below).
Standard Uncertainties and Uncertainty Budgets in % at Wavelength (Example)
400 500 600 800 1000 1200 1600 1800 2000 2400
Standard uncertainty k = 1 5,09 3,64 3,01 3,00 3,04 3,04 3,05 3,04 10,86 10,86
Expanded uncertainty k = 2 10,18 7,28 6,01 6,00 6,08 6,08 6,10 6,08 21,71 21,71
Place the light source horizontally. A value of 6 % of expanded uncertainty must be taken into account for
vertical placement.