High-energy ions’ movement affected by silicon crystal periodicity (Vol. 49, No. 3)

Simulated spatial and angular distributions for high-energy protons along a silicon axis.

Thinnest-ever silicon crystal enhances ion channelling performance in particle accelerators.

The thinner the silicon crystal, the better. Indeed, thinner crystals provide better ways to manipulate the trajectories of very high-energy ions in particle accelerators. Further applications include materials analysis, semiconductor doping and beam transport in large particle accelerators. All of these rely on our understanding of how positively-charged high-energy particles move through crystals. This process, called ion channelling, is the focus of a new paper published recently. In this paper, the authors study how the crystal periodicity affects the motion of ions whose energy belongs to a 1 to 2 MeV range, as they are transmitted through very thin crystals on the order of a few hundred nanometres, and how it impacts their angular distribution. What is so interesting about this work is that it relies on an advanced process of fabricating much thinner crystals than was previously possible, reaching 55 nanometres. This, in turn, makes it possible to observe much more sensitive and fine angular structures in the distribution of transmitted ions.

M. Motapothula and M. B. H. Breese, A study of small impact parameter ion channeling effects in thin crystals, Eur. Phys. J. B 91, 49 (2018)