The charge amplifier
The charge amplifier is examined. This is a particular type of amplifier using capacitive feedback and allowing the charge, developed in a high impedance detector on the occurrence of a short duration event, to reach the output. The charge amplifier is presented as the limit of an operational amplifier used to perform the integration of a signal in the case where the input resistance tends to infinity. The charge amplifier does not amplify the electric charge but it delivers at the output a voltage signal proportional to the charge and minimises the charge losses. It is normally developed as a low-noise pre-amplifier. In this paper the charge amplifier is studied at three different levels: the first is an elementary approach neglecting the effect of the input capacitances and the capacitance limiting the frequency band of the amplifier. In a second step the amplifier is considered with a pole limiting the band at the high frequency side. Finally the effect of the input capacitance is introduced, thus obtaining the case occurring in practice with the charge amplifier connected for example to a nuclear detector. The shape of the output signal in the real case is analytically derived and plotted.
Bibliographic Reference: EUR 12194 IT (1989) MF, 16 pp,. ECU 4, blow-up copy ECU 5
Record Number: 198910973 / Last updated on: 1994-12-01
Original language: it
Available languages: it