Characterization and beam test measurements of CMS Phase-2 luminometers

The physics program of the HL-LHC requires high-precision (%) luminosity determination. Two new luminosity detectors are being developed by the CMS BRIL (Beam Radiation, Instrumentation, and Luminosity) project: the Fast Beam Condition Monitor (FBCM), a standalone detector with unique timing capabilities, and the Tracker Endcap Pixel (TEPX) detector augmented with real-time cluster reconstruction in the FPGA of a dedicated back-end board at 10% of the full level-1 trigger rate. The innermost ring of the last TEPX disk (D4R1) will be fully dedicated to luminometry. The detectors were tested at the CERN T9 beam line with hadron, muon and electron beams. Results are presented for the FBCM detector prototype test for two sensor types with various irradiation levels. The firmware-based clustering algorithm for the FPGA of the TEPX detector is validated against a software clustering algorithm with the data harvested during the beam test.