Speaker
Описание
The ALICE experiment underwent significant upgrades during the LHC Long Shutdown 2 (2019–2021), including the installation the new Fast Interaction Trigger (FIT) system. Operating in the forward rapidity region of ALICE since 2021 (RUN 3), FIT comprises three detectors FT0, FV0 and FDD [1]. Experience with the FIT detector system has shown that FT0 is the primary detector for measuring global event characteristics. FT0 detector includes a Cherenkov subsystem utilizing 52 Planacon XP85002/FIT-Q microchannel plate-based photomultiplier tubes (MCP-PMTs).
FIT uses dedicated front-end electronics to measure the time and charge of pulses at bunch crossing interval of 25 ns and pp (Pb–Pb) interaction rates of up to 1 MHz (50 kHz).
In the online regime, the FIT detector provides an initial vertex position, fast triggers, beam luminosity, and background monitoring. The offline FIT data are important for event selection, determining and measuring multiplicity, centrality, collision time, event plane, and veto for diffractive and ultra-peripheral heavy-ion collisions. The FIT will stay in operation until the end of LHC RUN4 in 2033.
This talk gives an overview of our experience of operating Planacon MCP-PMTs in the harsh environment of the ALICE experiment’s forward region, FIT’s operational experience and performance, as well as its achievements and expected physics performance improvements.
[1] W. H. Trzaska et al., Nucl. Instrum. Methods A 958, 162116 (2020)
