COMPENSATED ION CHAMBER

Radiation Detectors COMPENSATED ION CHAMBER COMPENSATED ION CHAMBER Gamma compensation is required at intermediate reactor power levels to ensure accurate power reading. EO 2.4 DESCRIBE how a compensated ion chamber compensates for gamma radiation. Compensating for the response to gamma rays extends the useful range of the ionization chamber. Compensated ionization chambers consist of two separate chambers; one chamber is coated with boron, and one chamber is not. The coated chamber is sensitive to both gamma rays and neutrons, while the uncoated chamber is sensitive only to gamma rays. Instead of having two separate ammeters and subtracting the currents, the subtraction of these currents is done electrically, and the net output of both detectors is read on a single ammeter. If the polarities are arranged so that the two chambers’ currents oppose one another, the reading obtained from the ammeter indicates the difference between the two currents. One plate of the compensated ion chamber is common to both chambers; one side is coated with boron, while the other side is not. Figure 19 shows the basic circuitry for a compensated ion chamber. Figure 19 Compensated Ion Chamber Rev. 0 Page 35 IC-06