How is the Grounded connection technology/mode working?
There are two different methods for connecting ionization chambers to an electrometer: Floated
and Grounded input technology. The main difference between the two systems is the way in which the polarization voltage is supplied to the ionization chamber.
The grounded input clamps the electrometer amplifier on ground potential and provides the polarization voltage to the outer chamber wall.
With grounded input technology, typically all electrical components inside the electrometer are on ground potential. With grounded input, the construction of cables and sensors is more demanding, for the following reasons:
- The chamber wall is on polarization voltage, and an additional isolating sleeve is necessary to protect from electrical hazard and leakage current, especially when used in water.
- As the chamber wall is not grounded, RF noise may enter into the chamber and cause problems under all RF operated particle accelerators.
- If a triaxial cable is used, the connectors become complicated, because at the inside the connector’s inner and outer shielding must be crossed to get the outer shell of the connector on ground level. The same occurs inside the chamber, if a conductive (metal) chamber body has to be grounded.