Speaker
Description
The next generation of experiments searching for neutrinoless double-beta (0νββ) decay requires very low radioactive backgrounds. LEGEND—the Large Enriched Germanium Experiment for Neutrinoless ββ Decay—builds on previous success in this area by the Ge-based GERDA and MAJORANA DEMONSTRATOR experiments, and aims for a sensitivity beyond 10^28 years on the 0νββ decay half-life of 76Ge, requiring a ~30⨉ reduction in background. The close proximity of the front end electronics to each detector poses a unique challenge for the radiopurity of the electronics. A JFET-based low mass front end (LMFE) is successfully employed in MAJORANA and LEGEND-200. LEGEND-1000, the next step in scaling detector mass and reducing backgrounds, would utilize a dedicated application-specific integrated circuit (ASIC) preamplifier. Features include a high dynamic range (9 MeV) with sufficiently low noise to provide a suitable triggering threshold of <1 keV. A single power supply alleviates the need for additional background-contributing cables. A differential output maintains signal integrity on the ~10 m transmission line to the data acquisition electronics. Dedicated on-chip low-dropout regulators obviate the need for radioactive external bypass capacitors. The ASIC is optimized for operation in liquid argon (87 K). This talk summarizes the development and characterization of our first prototypes (v1) and the design of the second generation device (v2).
