A Low-Noise Charge-Sensitive Amplifier for Gainless Charge Readout in High-Pressure Gas TPC

TWEPP 2018Topical Workshop on Electronics for Particle Physics. https://indico.cern.ch/event/697988/contributions/3056035/ We present a low-noise Charge-Sensitive Amplifier (CSA) manufactured in a standard 0.35 μm CMOS process. The CSA is part of an integrated sensor named Topmetal-S, with an array of which, forms a charge readout plane in a high-pressure gaseous Time Projection Chamber (TPC) for 0νββ search. A single-ended folded cascode amplifier with a 73 dB open-loop gain and 340 MHz gain-bandwidth product forms the main amplification stage in this CSA. Measurements show that the conversion gain of the CSA with a 3 fF feedback capacitor is 168 mV/fC. The equivalent noise charge of the CSA after a trapezoidal pulse shaper is 28.7erms with a 5 pF detector capacitance. Introduction Topmetal sensor for a next-generation high-pressure gaseous (TPC) to search for neutrinoless double-beta decay (0υββ): Ø Topmetal sensor advantage: directly collecting ionization charges without gas-electron multiplication Ø Energy resolution: < 1% FWHM Ø Charge Collection Electrode : 1 mm diameter Ø Pitch: 5 mm Ø 105 sensors for a large plane