Radiation Detectors
DETECTOR VOLTAGE
Figure 6 Ion Pairs Collected -vs- Applied Voltage
Recombination Region
In the recombination region (Region I), as voltage increases to V1, the pulse height
increases until it reaches a saturation value. At V1, the field strength between the cathode
and anode is sufficient for collection of all ions produced within the detector. At voltages
less than V1, ions move slowly toward the electrodes, and the ions tend to recombine to
form neutral atoms or molecules. In this case, the pulse height is less than it would have
been if all the ions originally formed reached the electrodes. Gas ionization instruments
are, therefore, not operated in this region of response.
Rev. 0
Page 15
IC-06
