The Stonehenge Technique. A new method for aligning coherent bremsstrahlung radiators

TL;DR

This paper introduces a novel alignment technique for crystal radiators in coherent bremsstrahlung experiments, improving the setup process for producing polarized photons at electron beam facilities.

Contribution

It presents a new method for aligning crystal radiators, including detailed equations and practical guidance for installation and operation.

Findings

Effective alignment demonstrated at MAMI facility

Improved precision in crystal orientation control

Simplified setup process for coherent bremsstrahlung

Abstract

This paper describes a new technique for the alignment of crystal radiators used to produce high energy, linearly polarized photons via coherent bremsstrahlung scattering at electron beam facilities. In these experiments the crystal is mounted on a goniometer which is used to adjust its orientation relative to the electron beam. The angles and equations which relate the crystal lattice, goniometer and electron beam direction are presented here, and the method of alignment is illustrated with data taken at MAMI (the Mainz microtron). A practical guide to setting up a coherent bremsstrahlung facility and installing new crystals using this technique is also included.