The broad physics programme at the FCC-ee calls for next-generation calorimeters offering high granularity, high energy resolution and allowing for low systematics in measurements. The ALLEGRO electromagnetic calorimeter is a novel noble liquid calorimeter design aiming to achieve these goals by using multi-layer PCBs to achieve high granularity and optimising the design for best energy resolution. Progress in the implementation of the simulation and reconstruction of both barrel and endcap geometries yields promising performance metrics. R&D on all main calorimeter elements is progressing in parallel, with first electrodes and absorber prototypes delivering the expected performance figures. Design studies on the readout electronics and on the mechanical structures are progressing, along with developments for lightweight cryostats made of carbon fiber composites. The plans for a full-scale prototype aiming for beam tests after the Long Shutdown 3 of the LHC are also discussed.
Nicolas Morange (Wed,) studied this question.