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@ARTICLE{Alme:165890,
      author       = {J. Alme and G. G. Barnaföldi and R. Barthel and V.
                      Borshchov and T. Bodova and A. v. d. Brink and S. Brons and
                      M. Chaar and V. Eikeland and G. Feofilov and G. Genov and S.
                      Grimstad and O. Grøttvik and H. Helstrup and A. Herland and
                      A. E. Hilde and S. Igolkin and R. Keidel and C. Kobdaj and
                      N. v. d. Kolk and O. Listratenko and Q. W. Malik and S.
                      Mehendale and I. Meric and S. V. Nesbø and O. H. Odland and
                      G. Papp and T. Peitzmann and H. E. S. Pettersen and P.
                      Piersimoni and M. Protsenko and A. U. Rehman and M. Richter
                      and D. Röhrich and A. T. Samnøy and J. Seco$^*$ and L.
                      Setterdahl and H. Shafiee and Ø. J. Skjolddal and E.
                      Solheim and A. Songmoolnak and Á. Sudár and J. R. Sølie
                      and G. Tambave and I. Tymchuk and K. Ullaland and H. A.
                      Underdal and M. Varga-Köfaragó and L. Volz$^*$ and B.
                      Wagner and F. M. Widerøe and R. Xiao and S. Yang and H.
                      Yokoyama},
      title        = {{A} {H}igh-{G}ranularity {D}igital {T}racking {C}alorimeter
                      {O}ptimized for {P}roton {CT}},
      journal      = {Frontiers in physics},
      volume       = {8},
      issn         = {2296-424X},
      address      = {Lausanne},
      publisher    = {Frontiers Media},
      reportid     = {DKFZ-2020-02459},
      pages        = {568243},
      year         = {2020},
      abstract     = {A typical proton CT (pCT) detector comprises a tracking
                      system, used to measure the proton position before and after
                      the imaged object, and an energy/range detector to measure
                      the residual proton range after crossing the object. The
                      Bergen pCT collaboration was established to design and build
                      a prototype pCT scanner with a high granularity digital
                      tracking calorimeter used as both tracking and energy/range
                      detector. In this work the conceptual design and the layout
                      of the mechanical and electronics implementation, along with
                      Monte Carlo simulations of the new pCT system are reported.
                      The digital tracking calorimeter is a multilayer structure
                      with a lateral aperture of 27 cm × 16.6 cm, made of 41
                      detector/absorber sandwich layers (calorimeter), with
                      aluminum (3.5 mm) used both as absorber and carrier, and two
                      additional layers used as tracking system (rear trackers)
                      positioned downstream of the imaged object; no tracking
                      upstream the object is included. The rear tracker’s
                      structure only differs from the calorimeter layers for the
                      carrier made of ∼200 μm carbon fleece and carbon paper
                      (carbon-epoxy sandwich), to minimize scattering. Each
                      sensitive layer consists of 108 ALICE pixel detector
                      (ALPIDE) chip sensors (developed for ALICE, CERN) bonded on
                      a polyimide flex and subsequently bonded to a larger
                      flexible printed circuit board. Beam tests tailored to the
                      pCT operation have been performed using high-energetic
                      (50–220 MeV/u) proton and ion beams at the Heidelberg
                      Ion-Beam Therapy Center (HIT) in Germany. These tests proved
                      the ALPIDE response independent of occupancy and
                      proportional to the particle energy deposition, making the
                      distinction of different ion tracks possible. The read-out
                      electronics is able to handle enough data to acquire a
                      single 2D image in few seconds making the system fast enough
                      to be used in a clinical environment. For the reconstructed
                      images in the modeled Monte Carlo simulation, the water
                      equivalent path length error is lower than 2 mm, and the
                      relative stopping power accuracy is better than $0.4\%.$
                      Thanks to its ability to detect different types of radiation
                      and its specific design, the pCT scanner can be employed for
                      additional online applications during the treatment, such as
                      in-situ proton range verification.},
      cin          = {E041},
      ddc          = {530},
      cid          = {I:(DE-He78)E041-20160331},
      pnm          = {315 - Imaging and radiooncology (POF3-315)},
      pid          = {G:(DE-HGF)POF3-315},
      typ          = {PUB:(DE-HGF)16},
      doi          = {10.3389/fphy.2020.568243/full},
      url          = {https://inrepo02.dkfz.de/record/165890},
}