Charge-sensitive amplifier front-end with an nJFET and a forward-biased reset diode

A new configuration of a resistorless charge sensitive preamplifier with an nJFET as an input device was tested. The DC level of the input of the amplifier was kept constant by a slightly forward-biased np junction connected between the input of the amplifier and ground. A noise level of 22 root mean square (r.m.s.) electrons is measured at 295 K and 15 r.m.s. electrons at 253 K. The dynamic behavior of the amplifier is investigated with different leakage current conditions. The technological benefits and the suitability of the front-end connection for room temperature detectors, particularly multianode drift chambers, are highlighted.