Beam Steering and Radiation Generation of Electrons in Bent Crystals in the Sub-GeV Domain

TL;DR

This study demonstrates effective beam steering and radiation generation by sub-GeV electrons in bent silicon crystals, showing high channeling efficiency and significant radiation enhancement, thus enabling advanced low-energy beam control and photon sources.

Contribution

It provides the first comprehensive experimental and simulation analysis of electron channeling and radiation in bent crystals at sub-GeV energies, with record low-energy channeling efficiency.

Findings

Channeling efficiency exceeds 50% at 300 MeV.

Radiation emission is enhanced up to six times with crystal orientation.

Crystal steering remains effective at energies as low as 300 MeV.

Abstract

We present an investigation into beam steering and radiation emission by sub-GeV electrons traversing bent silicon crystals. Using 855, 600, and 300~MeV electron beams at the Mainz Microtron (MAMI), we explored orientational coherent effects and particle dynamics in a 15~$\mu$m-thick crystal bent along the (111) planes. Combined experimental and simulation analyses enabled the classification and quantitative assessment of the contributions from channeling, dechanneling, rechanneling, and volume capture to both beam deflection and radiation emission. Crystal steering remained effective even at 300~MeV, with measured channeling efficiencies exceeding 50\%, a record at such low energy. Channeling and volume reflection enhanced radiation emission by up to a factor of six compared to the misaligned orientation, highlighting strong orientational coherence effects in the sub-GeV regime. These findings confirm the feasibility of using bent crystals for efficient beam manipulation and high-intensity photon generation at low energies, supporting the development of novel light sources and beam control strategies at accelerator facilities operating in this energy range.