Design and Experimental Validation of an Integrated Multichannel Charge Amplifier for Solid-State Detectors With Innovative Spectroscopic Range Booster

The circuit structure and the experimental performance of a newly integrated multichannel charge-sensitive preamplifier for silicon or germanium detectors are shown. The circuit has been conceived and optimized for the silicon detector GAL-TRACE, employed for light and heavy ion spectroscopy in nuclear physics experiments. The chip includes four channels optimized for anodic signals and one channel specifically designed for cathodic signals. An I2C interface is used to adjust, as needed, a host of key parameters of the preamplifier, such as sensitivity and bandwidth. An integrated range booster yields an exceptional dynamic range of 103 dB for the cathodic channel. The circuit features a low power consumption of 11 mW per channel, a fast rise time of the order of 10 ns, and low noise. Thanks to an accurate design of the input stage, the equivalent noise charge, measured with a commercial shaping amplifier, is as low as 130 rms electrons at a shaping time of 6 $\mu \text{s}$ with 5 pF of detector capacitance. The bandwidth of the preampifier is adequate for pulse shape analysis techniques used for particle discrimination.