Ocean Optics S2000 - Manual (Page 50)

1. After placing OOIBase32 into Scope Mode, take a spectrum of your light source. Adjust the integration time
until there are several peaks on the screen that are not off-scale.
2. Move the cursor to one of the peaks and carefully position it so that it is at the point of maximum intensity.
Record the pixel number that is displayed in the status bar (located beneath the graph). Repeat this step for all
of the peaks in your spectrum.
3. Using your spreadsheet, create a table like the one below. In the first column, place the exact or true
wavelength of the spectral lines that you used. The spectral lines of the HG-1 are printed on the lamp’s casing.
In the second column of this worksheet, place the observed pixel number. In the third column, calculate the
pixel number squared, and in the fourth column, calculate the pixel number cubed.
4. Now you are ready to calculate the wavelength calibration coefficients. In your spreadsheet program, find the
functions to perform linear regressions. If you are using Quattro Pro, look under Tools | Advanced Math. If
you are using Excel, look under Tools | Data Analysis.
5. Select the true wavelength as the dependent variable (Y). Select the pixel number, pixel number squared and
the pixel number cubed as the independent variables (X). After you execute the regression, an output similar
to the one shown below is obtained.
Regression Statistics
Multiple R 0.999999831
R Square 0.999999663
Adjusted R Square 0.999999607
Standard Error 0.125540214
Observations 22
Light Sources: HG-1
- 50 -
Independent Dependent Values computed from
Variable Variables the regression output
True
Wavelength
(nm)
Pixel # Pixel # 2 Pixel # 3
Predicted
Wavelength
Difference
253.65
296.73
302.15
313.16
334.15
365.02
404.66
407.78
435.84
546.07
576.96
579.07
696.54
706.72
727.29
738.40
751.47 175
296
312
342
402
490
604
613
694
1022
1116
1122
1491
1523
1590
1627
1669
30625
87616
97344
116964
161604
240100
364816
375769
481636
1044484
1245456
1258884
2223081
2319529
2528100
2647129
2785561
5359375
25934336
30371328
40001688
64964808
117649000
220348864
230346397
334255384
1067462648
1389928896
1412467848
3314613771
3532642667
4019679000
4306878883
4649101309
253.56
296.72
302.40
313.02
334.19
365.05
404.67
407.78
435.65
546.13
577.05
579.01
696.70
706.62
727.24
738.53
751.27 0.09
0.01
-0.25
0.13
-0.05
-0.04
-0.01
0.00
0.19
-0.06
-0.09
0.06
-0.15
0.10
0.06
-0.13
0.19
intercept
Coefficents Standard Error
Intercept 190.473993 0.369047536
first coefficient
X Variable 1 0.36263983 0.001684745
X Variable 2 -1.174416E-05 8.35279E-07
X Variable 3 -2.523787E-09 2.656608E-10
second coefficient
third coefficient