Pre-bunched Relativistic Electron Beam Focusing by Dielectric Capillary

Sep 16, 2019, 5:10 PM
Oral Diffraction radiation and Smith-Purcell radiation Diffraction Radiation and Smith-Purcell Radiation


Kristina Vokhmyanina (BelSU)


To date, large variety of a passive dielectric deflectors have been tested with keV electron beam for potential usage in the field of applied biology and medicine. However, there is an attraction to implement the same techniques for deflection and focusing of a low-emittance relativistic pre-bunched electron beam of a modern compact linear accelerator. To verify this possibility we have made initial experimental study at KEK LUCX facility where electron beam bunches with ps rms durations, nC charges and 8 MeV energy were transmitted through a multi-mode dielectric capillary. The 60 mm length capillary is assembled of 4 mm and 4.4 mm alternate inner diameter rings which formed a 250 um longitudinal period of the structure. The capillary is wrapped with a grounded copper tube with an internal diameter of 5.4 mm. It was shown that the shift of capillary axis parallel to the beam axis within the size of the beam cross section lead to the shift of the transmitted beam charge profile as observed at luminescent screen downstream of the capillary. At the same time, we have witnessed increase of the charge density at the screen what can be referred as a beam passive focusing by the dielectric capillary. Further investigations are foreseen to explore applicability of the given deflection/focusing scheme for femtosecond electron bunches and confirm the physics of observed phenomena.

This work was supported by the JSPS and RFBR under the Japan-Russia Research Cooperative Program (18-52-50002 YaF$\_$a), the Competitiveness enhancement program of Belgorod State University.

Primary authors

Kristina Vokhmyanina (BelSU) Alexander Aryshev (KEK) Alexandr Kubankin (Belgorod State University) Mr I.A. Kishin (Belgorod National Research University, Belgorod, Russia) Nobuhiro Terunuma junji urakawa (kek)

Presentation materials

There are no materials yet.