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@INPROCEEDINGS{Bilka:205298,
      author       = {Bilka, T. and Casarosa, G. and Frühwirth, R. and
                      Kleinwort, C. and Kodys, P. and Kvasnicka, P. and
                      Lettenbichler, J. and Paoloni, E. and Rauch, J. and
                      Schlüter, T. and Yashchenko, S.},
      title        = {{D}emonstrator of the {B}elle {II} {O}nline {T}racking and
                      {P}ixel {D}ata {R}eduction on the {H}igh {L}evel {T}rigger
                      {S}ystem},
      reportid     = {PUBDB-2014-04700, arXiv:1406.4955},
      year         = {2014},
      note         = {OA},
      abstract     = {We present a computer-farm based data reduction system for
                      the future Belle II experiment. Belle II will collect data
                      from SuperKEKB, an asymmetric $e^+e^-$ collider whose target
                      luminosity $(8x10^35$ $Hz/cm^2)$ is a factor 40 larger than
                      the present world record held by KEKB. The higher trigger
                      rate (10 kHz) and worse background conditions $(3\%$ average
                      occupancy on the pixel sensors) are a major challenge for
                      both the detectors and the DAQ, in particular for the inner
                      part of the Belle II tracking system that consists of two
                      cylindrical layers of DEPFET pixels sensors (PXD) placed
                      just outside the beam pipe, very close to the Interaction
                      Point (IP). The long integration times of the PXD together
                      with the high background rate expected will lead to a large
                      amount of data (> 20 GB/s) that must be reduced at least
                      tenfold. A large amount of background hits can be rejected
                      by defining a set of Region Of Interest (ROI) on the PXD
                      sensors and then recording just the data from the pixels
                      inside the ROI. The ROIs are defined on an event by event
                      basis by extrapolating back onto the PXD the charged tracks
                      detected in the outer silicon tracker and reconstructed
                      online in real time. A demonstrator of this architecture was
                      under beam test earlier this year in DESY. The demonstrator
                      was operated in an electron beam (2-6 GeV/c) with a typical
                      trigger rate of a few kHz in a magnetic field of strength up
                      to 1 T. The demonstrator consists of one PXD sensor and 4
                      SVD sensors arranged in a 5 layer configuration mimicking
                      the Belle II vertex detector. The detector readout was a
                      scaled down version of the full Belle II DAQ + High Level
                      Trigger chain. The demonstrator was used to detect the
                      particles, reconstruct in real time the trajectories,
                      identify the ROIs on the PXD plane and record the PXD data
                      within. We describe the requirements and the architecture of
                      the final system together with the results obtained.},
      month         = {May},
      date          = {2014-05-26},
      organization  = {19th Real Time Conference, Nara
                       (Japan), 26 May 2014 - 30 May 2014},
      keywords     = {semiconductor detector: pixel (INSPIRE) / computer: network
                      (INSPIRE) / BELLE (INSPIRE) / trigger (INSPIRE) / background
                      (INSPIRE) / data acquisition (INSPIRE) / vertex detector
                      (INSPIRE) / electron: irradiation (INSPIRE)},
      cin          = {Belle},
      cid          = {I:(DE-H253)Belle-20160426},
      pnm          = {Experiments at KEK (BELLE I/II) (POF2-515)},
      pid          = {G:(DE-H253)POF2-BELLE-I-II-Exp.-20130405},
      experiment   = {EXP:(DE-H253)BELLE-20150101},
      typ          = {PUB:(DE-HGF)8 / PUB:(DE-HGF)15},
      eprint       = {1406.4955},
      howpublished = {arXiv:1406.4955},
      archivePrefix = {arXiv},
      SLACcitation = {$\%\%CITATION$ = $arXiv:1406.4955;\%\%$},
      url          = {https://bib-pubdb1.desy.de/record/205298},
}