Broad angular anisotropy of multiple scattering in a Si crystal

TL;DR

This study demonstrates that electron scattering in silicon crystals can be significantly reduced through orientation control, with potential improvements for detector modeling in various physics applications.

Contribution

It provides the first detailed experimental evidence of angular-dependent suppression of multiple scattering in silicon crystals compared to amorphous silicon.

Findings

Maximum 7% reduction in scattering angle at specific crystal orientations.

Partial reduction observed over a wide range of beam alignments up to 15 degrees.

Experimental results align with theoretical predictions and Monte Carlo simulations.

Abstract

We observed reduction of multiple Coulomb scattering of 855 MeV electrons within a Si crystalline plate w.r.t. an amorphous plate with the same mass thickness. The reduction owed to complete or partial suppression of the coherent part of multiple scattering in a crystal vs crystal orientation with the beam. Experimental data were collected at Mainz Mikrotron and critically compared to theoretical predictions and Monte Carlo simulations. Our results highlighted maximal 7 % reduction of the r.m.s. scattering angle at certain beam alignment with the [100] crystal axes. However, partial reduction was recorded over a wide range of alignment of the electron beam with the crystal up to 15 deg. This evidence may be relevant to refine the modelling of multiple scattering in crystals for currently used software, which is interesting for detectors in nuclear, medical, high energy physics.