Radiation tolerance of online trigger system for COMET Phase-I

Sam Dekkers, Yu Nakazawa, Yuki Fujii, Hisataka Yoshida, Ting Sam Wong, Kazuki Ueno, Jordan Nash

Research output: Contribution to journalArticleResearchpeer-review


The CO herent M uon to E lectron T ransition (COMET) experiment aims to search for the neutrinoless muon to electron transition process with new sensitivity levels. The online trigger system is an integral part of achieving the sensitivity levels required and will be subject to an expected neutron fluence of up to 1012n⋅cm−2 within regions inside the detector solenoid. Consequently, a significant number of soft errors in the logic of the onboard field programmable gate arrays (FPGAs) can occur, requiring error correction for single event upsets and firmware reprogramming schemes for unrecoverable soft errors. We studied the radiation tolerance of the COMET Phase-I front-end trigger system, called CO ME T TRI gger (COTTRI), subject to neutron fluence on order 1012n⋅cm−2 with multiple error correcting codes and automatic firmware reconfiguration. The regions measured were the configuration random access memory (RAM), block RAM (BRAM) and also in a multigigabit transfer link using copper cables that will be used for communication between different trigger boards during Phase-I. The resulting cross sections observed suggest the most significant impact to the experiment will come from unrecoverable soft errors in configuration RAM (CRAM), with dead time expected to be 4.2% ± 1.3%. The effect of multibit errors in BRAM was found to be almost negligible in COMET Phase-I. In addition, multiple solutions have already been proposed in order to suppress these errors further. Soft errors observed in the multigigabit transfer links were measured to be of two orders of magnitude less impact compared to the unrecoverable errors in CRAM. We concluded that the COTTRI system meets the trigger requirement in COMET Phase-I.

Original languageEnglish
Pages (from-to)2020-2027
Number of pages8
JournalIEEE Transactions on Nuclear Science
Issue number8
Publication statusPublished - 31 May 2021


  • Data collection
  • Detectors
  • Field programmable gate arrays
  • Field Programmable Gate Arrays
  • Iron
  • Mesons
  • Multi-gigabit Data Transfer
  • Neutron Radiation
  • Neutrons
  • Particle beams
  • Particle Physics Experiment
  • Trigger System

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