M. D’Andrea, V. Avati, R. Bruce, M.E.J. Butcher, M. Deile, M. Di Castro, H. García Morales, S. Jakobsen, J. Kašpar, I. Lamas Garcia, A. Masi, A. Mereghetti, D. Mirarchi, S. Redaelli, B. Salvachúa, P. Serrano Galvez, M. Solfaroli Camillocci
CERN, Geneva, Switzerland
Yu.A. Gavrikov
PNPI, Gatchina, Leningrad District, Russia
K.H. Hiller
DESY Zeuthen, Zeuthen, Germany
N. Turini
UNISI, Siena, Italy
Bent crystals can deflect charged particles by trapping them within the potential well generated by neighboring crystalline planes and forcing them to follow the curvature of the crystal itself. This property has been extensively studied over the past decade at the CERN accelerator complex, as well as in other laboratories, for a variety of applications, ranging from beam collimation to beam extraction and in-beam fixed target experiments. In 2018, crystal collimators were operationally used for the first time at the Large Hadron Collider (LHC) during a special high-beta* physics run with low-intensity proton beams, with the specific goal of reducing detector background and achieving faster beam halo removal. This paper describes the preparatory studies carried out by means of simulations, the main outcomes of the special physics run and plans for future uses of this innovative collimation scheme, including the deployment of crystal collimation for the High-Luminosity LHC upgrade.
M. Patecki, D. Kikoła
Warsaw University of Technology, Warsaw, Poland
A.S. Fomin, D. Mirarchi, S. Redaelli
CERN, Geneva, Switzerland
Funding:This project has received funding from the European Union’s Horizon 2020 research and innovation programme. The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) is the world largest and most powerful particle accelerator colliding beams of protons and lead ions at energies up to 7 TeV and 2.76 TeV, respectively. ALICE is one of the detector experiments optimised for heavy-ion collisions. A fixed-target experiment in ALICE is considered to collide a portion of the beam halo split by means of a bent crystal with an internal target placed a few meters upstream of the detector. Fixed-target collisions offer many physics opportunities related to hadronic matter and the quark-gluon plasma to extend the research potential of the CERN accelerator complex. This paper summarises our progress in preparing the fixed-target layout consisting of crystal assemblies, a target and downstream absorbers. We discuss the conceptual integration of these elements within the LHC ring, impact on ring losses, conditions for a parasitic operation and expected performance in terms of particle flux on target.
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