Excell Ocean Specifications download pdf (Page 20)

A: Calibrating the Wavelength of the HR4000

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Calibrating the Spectrometer

Preparing for Calibration

To recalibrate the wavelength of your spectrometer, you need the following components:

• A light source capable of producing spectral lines

Note

Ocean Optics’ HG-1 Mercury-Argon lamp is ideal for recalibration. If you do not have an

HG-1, you need a light source that produces several (at least 4-6) spectral lines in the

wavelength region of your spectrometer.

• An HR4000 spectrometer

• An optical fiber (for spectrometers without a built-in slit, a 50-

µm fiber works best)

• A spreadsheet program (Excel or Quattro Pro, for example) or a calculator that performs third-

order linear regressions

Note

If you are using Microsoft Excel, choose Tools | Add-Ins and check AnalysisToolPak

and AnalysisTookPak-VBA.

Calibrating the Wavelength of the Spectrometer

► Procedure

Perform the steps below to calibrate the wavelength of the spectrometer:

1. Place the operating software into Quick View (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 in the following

figure. 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.

1 2 ... 15 16 17 18 19 20 21 22 23 24 25 ... 34 35

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Excell Ocean Specifications Page 20