Ocean Optics USB2000 - Manual (Page 37)

Appendix A
USB2000 Operating Instructions 32
Calibrating the Wavelength of the Spectrometer
Perform the steps below to calibrate the wavelength of the spectrometer:
1. Place OOIBase32 into Scope Mode and take a spectrum of your light source. Adjust the integration time
(or the A/D conversion frequency) until there are several peaks on the screen that are not off-scale.
2. Move the cursor to one of the peaks and position the cursor so that it is at the point of maximum intensity.
3. Record the pixel number that is displayed in the status bar or legend (located beneath the graph). Repeat
this step for all of the peaks in your spectrum.
4. Use the spreadsheet program or calculator to create a table like the one shown below. In the first column,
place the exact or true wavelength of the spectral lines that you used.
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.
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
(Continued)
Independent
Variable
Dependent
Variables
Values Computed
from the Regression
Output