The CMS Fast Beam Condition Monitor for HL-LHC

G. Auzinger, H. Bakhshiansohi, A. Dabrowski, A. G. Delannoy, A. Dierlamm, M. Dragicevic, A. Gholami, G. Gomez, M. Guthoff, M. Haranko, A. Homna, M. Jenihhin, J. Kaplon, O. Karacheban, B. Korcsmáros, W. H. Liu, A. Lokhovitskiy, R. Loos, S. Mallows, J. MichelV. Myronenko, G. Pásztor, M. Pari, J. Schwandt, M. Sedghi, A. Shevelev, K. Shibin, G. Steinbrueck, D. Stickland, B. Ujvari, G. J. Wegrzyn

Research output: Contribution to journalArticlepeer-review

Abstract

The high-luminosity upgrade of the LHC brings unprecedented requirements for real-time and precision bunch-by-bunch online luminosity measurement and beam-induced background monitoring. A key component of the CMS Beam Radiation, Instrumentation and Luminosity system is a stand-alone luminometer, the Fast Beam Condition Monitor (FBCM), which is fully independent from the CMS central trigger and data acquisition services and able to operate at all times with a triggerless readout. FBCM utilizes a dedicated front-end application-specific integrated circuit (ASIC) to amplify the signals from CO2-cooled silicon-pad sensors with a timing resolution of a few nanoseconds, which enables the measurement of the beam-induced background. FBCM uses a modular design with two half-disks of twelve modules at each end of CMS, with four service modules placed close to the outer edge to reduce radiation-induced aging. The electronics system design adapts several components from the CMS Tracker for power, control and read-out functionalities. The dedicated FBCM23 ASIC contains six channels and adjustable shaping time to optimize the noise with regards to sensor leakage current. Each ASIC channel outputs a single binary high-speed asynchronous signal carrying time-of-arrival and time-over-threshold information. The chip output signal is digitized, encoded, and sent via a radiation-hard gigabit transceiver and an optical link to the back-end electronics for analysis. This paper reports on the updated design of the FBCM detector and the ongoing testing program.

Original languageEnglish (US)
Article numberC03048
JournalJournal of Instrumentation
Volume19
Issue number3
DOIs
StatePublished - Mar 1 2024

All Science Journal Classification (ASJC) codes

  • Instrumentation
  • Mathematical Physics

Keywords

  • Radiation-hard detectors
  • Si microstrip and pad detectors

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