Steering of Sub-GeV electrons by ultrashort Si and Ge bent crystals

Abstract

We report the observation of the steering of 855 MeV electrons by bent silicon and germanium crystals at the MAinzer MIkrotron. 15 $\mu$m long crystals, bent along (111) planes, were exploited to investigate orientational coherent effects. By using a piezo-actuated mechanical holder, which allowed to remotely change the crystal curvature, it was possible to study the steering capability of planar channeling and volume reflection vs. the curvature radius and the atomic number, Z. For silicon, the channeling efficiency exceeds 35 %, a record for negatively charged particles. This was possible due to the realization of a crystal with a thickness of the order of the dechanneling length. On the other hand, for germanium the efficiency is slightly below 10 % due to the stronger contribution of multiple scattering for a higher-Z material. Nevertheless this is the first evidence of negative beam steering by planar channeling in a Ge crystal. Having determined for the first time the dechanneling length, one may design a Ge crystal based on such knowledge providing nearly the same channeling efficiency of silicon. The presented results are relevant for crystal-based beam manipulation as well as for the generation of e.m. radiation in bent and periodically bent crystals.

12 pages, 10 figures, submitted to Eur. Phys. J. C

References in corpus (2)

• Crystalline Undulator with a Small Amplitude and a Short Period
• Experimental evidence of planar channeling in a periodically bent crystal

Cited by in corpus (11)

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• All-atom relativistic molecular dynamics simulations of channeling and radiation processes in oriented crystals
• Investigation on radiation generated by Sub-GeV electrons in ultrashort Si and Ge bent crystals
• Geant4 simulation model of electromagnetic processes in oriented crystals for accelerator physics
• Crystal-based pair production for a lepton collider positron source
• Investigation on steering of ultrarelativistic $e^{\pm }$ beam through an axially oriented bent crystal
• Atomistic modelling and characterizaion of light sources based on small-amplitude short-period periodically bent crystals
• First design of a crystal-based extraction of 6 GeV electrons for the DESY II Booster Synchrotron
• Investigation of Radiation Emitted by Sub GeV Electrons in Oriented Scintillator Crystals
• Mean volume reflection angle
• A Novel Tool for Advanced Analysis of Geant4 Simulations of Charged Particles Interactions in Oriented Crystals