A novel SiPM-based aerogel RICH detector for the future ALICE 3 apparatus at LHC.

The ALICE Collaboration is proposing a new apparatus, ALICE 3, to investigate the Quark Gluon Plasma properties for the LHC Runs 5 and 6. The measurements planned to address ALICE 3 physics goals require to identify charged particles over eight units of pseudorapidity ($|\eta|<4$) and to achieve a better than $3\sigma e/\pi$, $\pi/K$ and $K/p$ separation up to above 2 GeV/c, 10 $GeV/c$ and 16 GeV/c, respectively. In this context, conceptual studies for the design of complementary Ring-Imaging Cherenkov (RICH) and Time-Of-Flight (TOF) detectors are ongoing. The state-of-the-art detector concept for the ALICE 3 barrel RICH consists in a proximity-focusing layout, using aerogel ($n=1.03$ at $\lambda = 400$ nm) as Cherenkov radiator and a layer of Silicon Photomultipliers (SiPMs) for the photon detection. With the SiPM layer achieving a charged track time resolution of 20 ps, one could envisage merging ALICE 3 outer TOF and barrel RICH layers into a single one, thus considerably diminishing the overall costs. The latest barrel RICH specifications and performance simulations will be presented. The R&D challenges related to the proposed design will be also discussed.