Long range terahertz driven electron acceleration using phase shifters

Terahertz radiation (THz)-based electron acceleration has the potential as a technology for driving next-generation, compact ultrafast and ultrabright x-ray sources. Dephasing is one of key problems that prevent long THz–electron interaction lengths in sub- to few-MeV range, where velocities vary significantly during high-field acceleration. Here, we present phase-shifter design with double vacuum channels alternate phase velocity effectively extends length THz-powered dielectrically loaded waveguides. The electrons are swept multiple-times back forth through accelerating THz wave undergo continuous along entire interaction. In addition, channel enables increases both group wave, which leads an adaptive synchronous extended length. This method paves way practical implementation devices high-energy