Crystal fabrication techniques for enhanced performance in planar channeling

Bent crystals have emerged as innovative tools for manipulating high-energy particle beams, offering unparalleled precision in beam steering for accelerator physics. However, the practical application of these devices is hindered by nuclear dechanneling, limiting channeling efficiency to approximately 80%. The GALORE project addresses this limitation by introducing a novel bent crystal design featuring a microtrench structure. Acting as a crystalline lens, the microtrench minimizes nuclear interactions, thereby significantly enhancing channeling efficiency.

This paper details the fabrication process for these advanced bent crystals, utilizing high-purity silicon wafers and state-of-the-art micromachining techniques. A silicon nitride thin film induces controlled curvature, while Deep Reactive Ion Etching (DRIE) is employed to create the microtrench with sub-micron precision. Characterization studies confirm the structural integrity and channeling potential of the microstructures.

These results represent a significant milestone in the development of bent crystals capable of achieving near-ideal channeling efficiency—a breakthrough in crystal-assisted particle beam technology. This advancement holds the potential to revolutionize collimation systems, enhance fixed-target experiments, and shape the design of next-generation accelerators.