Teledyne Camera Accessories T100 Manual Do Utilizador

The performance of the analyzer’s PMT is significantly affected by temperature.  
Variations in PMT temperature are directly reflected in the signal output of the PMT. 
Also the signal to noise ratio of the PMT output is radically influenced by temperature 
as well. The warmer The PMT is, the noisier its signal becomes until the noise renders 
the concentration signal useless.  To alleviate this problem a special cooling system 
exists that maintains the PMT temperature at a stable, low level. 

PCA 

PCA 

Thermistor 

outputs temp of 

cold block to 

preamp PCA 

Preamp PCA sends 

buffered and 

amplified thermistor 

signal to TEC PCA 

TEC PCA sets 

appropriate 

drive voltage 

for cooler 

Heat form PMT is absorbed 

by the cold block and 

transferred to the heat sink 

via the TEC then bled off 

into the cool air stream. 

ThermoElectric Cooler 

 

 

13.5.4.1. THERMOELECTRIC COOLER (TEC) 

The core of the T100 PMT cooling system is a solid state heat pump called a 
thermoelectric cooler (TEC).  Thermoelectric coolers transfer heat from a one side of a 
special set of semiconductor junctions to the other when a DC current is applied. The 
heat is pumped at a rate proportional to the amount of current applied.  In the T100 the 
TEC is physically attached to a cold block that absorbs heat directly from the PMT and a 
heat sink that is cooled by moving air (refer to Figure 13-19). A Thermocouple 
embedded into the cold block generates an analog voltage corresponding to the current 
temperature of the PMT. The PMT Preamp PCA conditions and amplifies this signal 
then passes it on to the TEC Control PCA. 

06807C DCN6650