Calibration, Maintenance, and Troubleshooting
StarBright User Manual
98
To update sensor calibration factors:
1.
Press
Menu
and select
Calibration
.
2.
Press
Continue
twice to activate calibration. The information screens vary per sensor.
3.
The main Measurement screen appears, displaying the
Calibration Factor
value (on the left).
4.
Press
Modify
. The screen displays the
Original
(current) reading and factor (on the left side of
the screen), and
Updated
factor and its effect on the reading (on the right). The
Updated
box
is highlighted, indicating it is modifiable.
5.
In the
Updated
area, use the Right/Left arrows to select the digit to update. Use the Up/Down
arrows to change the value of the selected digit.
6.
Press
Save
to save the settings and return to the main Measurement screen, which now
displays the updated Calibration Factor.
7.
Press
Exit
to return to the Menu screen.
14.2
Calibration of Thermopile Sensors
14.2.1
Absorber Types and Method of Calibration of Ophir Power Meters
Types of Ophir Laser Absorbers
Two types of absorber surfaces are used in Ophir Thermopile measuring sensors.
14.2.2
Surface Absorbers
BB (Broadband) Absorber
On standard, high power density, broadband Ophir power monitor sensors, a special refractory
coating is used to provide high absorptivity from the UV through the IR. This coating can withstand
very high power densities, up to 28 kW/cm², without changing calibration. The absorption of this
coating is above 85% for most of its range, as shown in
EX (Excimer) Absorber
The EX absorber provides high absorption in the UV, and it can withstand both the pulse energies
and the average power of excimer lasers. These discs also have excellent absorption for 10.6 µm
and other wavelengths. They can therefore be used for other types of lasers as well. The
absorption of the various Ophir absorbers as a function of wavelength is shown in
LP1 (Long Pulse) Absorber
The LP1 absorber has a very high damage threshold for long pulse (ms) or continuous lasers
and is therefore offered for use with high power and energy lasers. It is calibrated for the spectral
range 250 – 2200nm with some sensors also being calibrated for 2940nm.
