The Phase-2 Upgrade of the CMS Data Acquisition

The High Luminosity LHC (HL-LHC) will start operating in 2027 after the third Long Shutdown (LS3), and is designed to provide an ultimate instantaneous luminosity of 7:5 × 10 34 cm −2 s −1 , at price extreme pileup up 200 interactions per crossing. number overlapping HL-LHC collisions, their density, resulting intense radiation environment, warrant almost complete upgrade CMS detector. upgraded detector be read out by approximately fifty thousand highspeed front-end optical links unprecedented data rate 80 Tb/s, for average expected total event size 8 − MB. Following present established design, trigger acquisition system continue feature two levels, with only one synchronous hardware-based Level-1 Trigger (L1), consisting custom electronic boards on dedicated streams, a second level, Level (HLT), using software algorithms running asynchronously standard processors making use full select events offline storage analysis. collect fragments accepted from back-end modules 750 kHz, aggregate corresponding individual Level- 1 accepts into events, distribute them HLT where they filtered further. Events stored permanently 7.5 kHz. This paper describes baseline design DAQ systems Phase-2 CMS.