000003592 001__ 3592
000003592 005__ 20230523033529.0
000003592 037__ $$aBELLE2-MTHESIS-2023-012
000003592 041__ $$aeng
000003592 100__ $$aPing Ni
000003592 245__ $$aUpgrade of Two Dimensional Track Trigger on Central Drift Chamber aimed for Belle II Targeted Luminosity
000003592 260__ $$aTokyo$$bUniversity of Tokyo, Department of Physics, Graduate School of Science$$c2022
000003592 300__ $$amult. p
000003592 500__ $$aPresented on 09 08 2022
000003592 502__ $$aMSc$$bTokyo, University of Tokyo$$c2022
000003592 520__ $$aThe Belle II experiment hosted by KEK has started taking physics data since 2019, committed to finding new physics beyond the Standard Model. The SuperKEKB has been upgraded to collide e− and e+ beams with a designed luminosity of 6×1035 cm−2s−1 which is 30 times higher than the predecessor, the Belle experiment. Accompanied by the higher luminosity is the higher beam-originated background, making it challenging to operate the Level-1 trigger system while keeping high efficiency for physics events and trigger rate smaller than the limit of 30 kHz. We evaluate the performance of the 2D track trigger at the designed luminosity with Monte Carlo simulation and clarify that the trigger rate is expected to exceed the limit of 30 kHz due to fake tracks. An upgraded 2-dimensional tracking algorithm named “Full-hit algorithm” has been developed in order to resolve this issue. The algorithm is designed as a simulation software and succeeded in reducing the trigger rate from the fake tracks below 1 kHz. The algorithm is optimized as a digital circuit on the Field Programmable Gate Array and successfully implemented in a new generation of the Belle II universal trigger board. The Full-hit is under commissioning and is planned to be used for physics operation in 2023 after the long shutdown of the Belle II.
000003592 8560_ $$ftaichiro.koga@outlook.jp
000003592 8564_ $$uhttps://docs.belle2.org/record/3592/files/BELLE2-MTHESIS-2023-012.pdf
000003592 980__ $$aTHESIS