Gentec-EO UP and XLP12 - Manual (Page 35)

Version 5.0
Ultra Series UP Instruction Manual Gentec Electro-Optics Inc. All rights reserved
31
2.1 WITH ANY GENTEC-EO MONITOR
To make a measurement Gentec-EO monitor, continue with the following steps:
4. Connect the detector head to the input socket on the monitor (see the monitor’s instruction
manual).
5. Block off the detector head to prevent it from sensing heat from random sources.
6. Once the reading is thermally stable, the reading should be set to 0 W with the monitor’s
Zero (Offset) function (see the monitor’s instruction manual).
7. Allow the detector head to thermally stabilize before making any subsequent measurement
reading.
2.2 WITHOUT A GENTEC-EO MONITOR
To make a measurement without a Gentec-EO monitor, continue with the following steps:
4. Let the head thermally stabilize for at least 10 minutes, and set up cooling (if fan- or water-
cooled).
5. Connect the power head to a precision microvoltmeter, or data acquisition system, with a
load impedance that is >100 k

(UP without internal circuit board) or with a load impedance
>10 M Ω (UP with internal circuit board). Because of the very low voltages at lower power
levels for some of these detectors, analog or digital filtration may be required to remove
ambient electrical noise.
6. Put the power head into the laser beam path (the laser beam must be contained within the
sensor area) for about one minute.
7. Block off any laser radiation to the detector.
8. Switch on the microvoltmeter and adjust its voltage range to the range required for the range
required for the measurement. To determine the voltage range to be measured, refer to the
detector head specifications:
Vout = (expected power) x (calibration sensitivity of power detector)
9. Wait until the signal has stabilized (fluctuations representing less than 1% of the voltage level
being measured are negligible) then, measure the zero level voltage offset from the
detector. Strong fluctuations in the zero level are usually caused by one of the following:

Rapid fluctuations in the rate of water flow.

Rapid fluctuations in water temperature.

Strong drafts or stray radiation (especially visible when you are
taking low power measurements)

Ambient electrical noise (should be filtered out).
10. Apply the laser beam to the power head.
11. Wait until the signal has stabilized (between one to three minutes for optimum
measurements), then measure the voltage output from the detector (refer to specifications
pages for individual head 0-95% non anticipated response times).
12. The measured power is calculated as follows: