Newport 1815-C, Operator'S Manual

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2.4.4 Setting the Detector Calibration Factor
The calibration factor tells the Model 1815-C how to account for a detector’s
responsivity at the measurement wavelength. Each Newport detector arrives
with calibration information. The information will reflect detector
responsivities and calibration factors. A calibration factor is calculated from a
responsivity by simply taking the inverse of the responsivity and expressing it
in scientific notation, i.e. d.ddE
±
d.
Example 1: Responsivity R = 0.568 A/W thus the Calibration Factor = 1.76
E
+
0 W/A
Example 2: Responsivity R = 0.346 mV/W thus the Calibration Factor =
2.89 E
+
3 W/V
Note
Be sure to re-express the responsivity value in units of A/W or V/W
before calculating the inverse. See Example 2 above.
2.4.4.1 Setting the Calibration Factor Mantissa
The mantissa of the calibration factor is the d.dd of the full calibration factor
value d.ddE
±
d. The mantissa is the most frequent calibration adjustment
made when making measurements at various wavelengths. To set the man-
tissa, use the following procedure:
1. Press the front panel CAL button into its depressed position.
2. Adjust the front panel CAL ADJ until the display matches the calibration
factor mantissa.
Example: If the Calibration Factor = 2.89 E
+
3, then the display should
indicate 2.89.
3. Release the CAL button from its depressed position.
NOTE
Set the calibration factor mantissa with the Accelerator circuit
turned off. (SETUP DIP switch position 4)
2.4.4.2 Setting the Calibration Factor Exponent
The calibration factor exponent is the
±
d of the full calibration factor value
d.ddE
±
d discussed in Section 2.4.4. The exponent rarely needs to be set more
than once when using the Model 1815-C with a particular detector. However it
is still wise to check that the exponent does not need resetting when making
measurements at multiple wavelengths. To set the exponent (SETUP switch
position 3, see Section 2.2.3), use the following lookup table: