Charge sensitive preamplifier design optimization for low-pressure Micro-Megas gaseous detector operations

Using a bulk Micro-Megas (MM) detector an energy measurement can be obtained collecting the total charge reaching the mesh electrode connected to a low noise charge sensitive preamplifier. When operating such a device in a low-pressure gas regime, it is necessary to modify the amplification gap geometry to reach the optimal detector gain. This implies changes in the input capacitance of the preamplifier influencing its signal to noise ratio and thus the detector energy resolution. An ad-hoc high-gain and low-noise charge preamplifier has been developed to cope with the requirements of our application field. In this short report, we present the development activities focused to the study of a configurable charge amplifier to be connected to a MM detector having different mesh capacitances.