Teledyne 9110T instruction manual Photomultiplier Tube PMT Sensor Module, Optic Test

Model 9110T NOx Analyzer Troubleshooting & Service

12.7.12. PHOTOMULTIPLIER TUBE (PMT) SENSOR MODULE

The PMT detects the light emitted by the reaction of NO with ozone. It has a gain of about 500000 to 1000000. It is not possible to test the detector outside of the instrument in the field. The basic method to diagnose a PMT fault is to eliminate the other components using ETEST, OTEST and specific tests for other sub-assemblies.

12.7.12.1. Optic Test

The optic test function tests the response of the PMT sensor by turning on an LED located in the cooling block of the PMT (see Figure 13-20). The analyzer uses the light emitted from the LED to test its photo- electronic subsystem, including the PMT and the current to voltage converter on the pre-amplifier board.

∙To ensure that the analyzer measures only the light coming from the LED, the analyzer should be supplied with zero air.

∙The optic test should produce a PMT signal of about 2000±1000 mV.

To activate the optics test, press:

Note	This is a coarse test for functionality and not an accurate calibration tool.
	The resulting PMT signal can vary significantly over time and also
	changes with low-level calibration.

Teledyne Analytical Instruments 300