Table 9-1: Test Functions - Teledyne 6400A Instruction Manual

TAI Model 6400A SO
Table 9-1: Test Functions (Continued)
Test Function Factory Set-Up
STR LGT 0 - 100 ppb
DRK PMT -50 - +200 mV
DRK LMP -50 - +200 mV
(table continued)
Analyzer Operator Manual, 02164, Rev. G
2
Comment
Stray light is the background light of the reaction cell expressed
in ppb while sampling zero gas. High stray light could be
caused by :
Aging UV filter.
Contaminated reaction cell.
Light leak.
Pneumatic leak.
This is the reading of the PMT signal without the UV lamp.
When the shutter is energized, it blocks the UV light causing
complete darkness inside of the reaction cell. This darkness
reading by the PMT is monitored and compensated for any
PMT dark current drift.
High dark PMT reading could be due to:
Light leak.
Shutter not closing completely.
High PMT temperature.
High electronic offset.
This is the reading of the UV reference detector without the UV
lamp. When the shutter blocks the UV light, UV detector signal
is the dark current of the detector itself. This dark current is
monitored and compensated for any UV detector dark current
drift.
High dark UV detector could be caused by:
Light leak.
Shutter not closing completely.
High electronic offset.
9-6