Development of a readout electronic for the measurement of ionization in liquid xenon compton telescope containing micro-patterns

We report on the electronic dedicated to the acquisition of the ionization current signal induced by the interactions of γ-rays inside a Compton telescope with Liquid Xenon. In order to achieve sub-millimeter resolution we successfully adapted an existing ASIC originally designed for semi-conductor detector with low input capacitance and low dark current called IDeF-x-Lxe, and fabricated in a standard 0.35 μm CMOS technology. With a copper pad area of 0.25 in 2 of our first prototype, and a Micromegas micromesh located 50 μm above the anode used as Frisch grid, the noise measurement shows an ENC of ~100 e rms - thanks to a meticulous setup. Each part of the coupling between the detector and the electronic has been specially tailored to cope with temperature constraints and with noise requirements.