Teledyne 6020 - Photometric analyzer - Manual (Page 71)

Part II: 1-9
Photometric Analyzer Operational Theory 1
Teledyne Analytical Instruments
The HG (Mercury arc) source and its power supply reside in one
enclosure. A quartz lens focuses the energy into a beam for transmission.
WARNING: UNDER NO CIRCUMSTANCES SHOULD THE
SOURCE MODULE BE OPEN AND THE LAMP AL-
LOWED TO OPERATE UNLESS PERSONNEL IN
THE IMMEDIATE VICINITY ARE WEARING UV FIL-
TERING EYE GOGGLES.
1.6.2 Sample Cell
The sample cell rests in a module placed between the source and detector
module. The module contains the sample cell and optional heater and
thermistor for temperature-controlled sample cells.
1.6.3 Detector Module
The detector module houses the photo detector, chopper assembly, and
the signal processing stages of the electronics circuitry. The synchronized
chopper motor rotates at 1800 rpm. The detector type found in your ana-
lyzer can be identified from the letter in the model number (either B or P).
The filter wheel that carries the optical filters is marked with (M) for
measuring and R for reference filter. If you remove the filter wheel, you must
align a reference mark on the wheel with a reference mark on the shaft. When
the switch activating disc is removed, align with the marks on the switch plate
and motor mount when you put it back.
The phototube detector PC board contains the I to E converter stage,
second amplifier, logarithmic amplifier, inverter, and first stage of integration.
The solid state detector has its I to E converter stage built in on the detector PC
board. A system with a solid state detector has a second converter PC board
containing the second amplifier, logarithmic amplifier, inverter, and first stage
of integration.
The magnetically-activated reed switch is mounted on the motor mount.
Oscilloscope test points are available and are mounted on a bracket inside the
housing for explosion-proof models; test points are available on the outside in
the bottom for general-purpose units. An optional zero and/or span filter is
located in this module also.