Charge Amplification without Charge Leak Resistor

Charge amplification without the conventional charge leak resistor is considered. It is shown that any charge leak mechanism based on continuous conduction current would contribute noise. Pulsed conduction of current from the amplifier input avoids this problem. A method for pulsed removal of charge is proposed here, based on charge pumping via the detector capacitance and the gate-channel junction of the input field-effect transistor. In this configuration the detector is the only component connected to the gate of the field-effect transistor, and these two are the only components required to be in the cryostat. The detector capacitance serves also as feedback capacitance.