High-Efficiency Volume Reflection of an Ultrarelativistic Proton Beam with a Bent Silicon Crystal

Abstract

The volume reflection phenomenon was detected while investigating 400 GeV proton interactions with bent silicon crystals in the external beam H8 of the CERN Super Proton Synchrotron. Such a process was observed for a wide interval of crystal orientations relative to the beam axis, and its efficiency exceeds 95%, thereby surpassing any previously observed value. These observations suggest new perspectives for the manipulation of high-energy beams, e.g., for collimation and extraction in new-generation hadron colliders, such as the CERN Large Hadron Collider.

Channeling through Bent Crystals

“…The angular profile plots match the overall form expected from previous research [2] with the volume reflection, capture, dechanneling and channeling effects taken into account in the code. Comparing the angular profiles in Fig.…”

“…This may improve the collimation of the beam which is important for preventing damage to equipment and improving the noise to signal ratio of experiments using the beam. Previous channeling experiments have examined this effect at circular accelerators including the RD22 experiment at the H8 beamline at the European Organization for Nuclear Research (CERN) [2] and the Tevatron at Fermilab [3].…”

Monte Carlo modeling of crystal channeling at high energies

“…It is taken from the results of the H8-RD22 experiment conducted at CERN [16] in which a strip crystal was operating in a 400 GeV/c proton beam and rotated so that the entire range of coherent phenomena could be observed. Fig.…”

Channeling efficiency dependence on bending radius and thermal vibration amplitude of the model for the channeling of high-energy particles in straight and bent crystals implemented in Geant4

“…For this purpose, the usage of orientational effect in curved crystal [1,2] was proposed as a realistic solution. The usage of bent crystals proved the capability to steering both positively [3,4] and negatively [5,6] charged particle beams. In particular, the usage of bent crystals as a primary collimator proved to reduce the beam losses for the SPS proton synchrotron at CERN [7][8][9], leading to the installation of two bent crystals in the LHC collider for a collimation experiment in 2015.…”