Experimental Demonstration of Energy-Chirp Compensation by a Tunable Dielectric-Based Structure

Abstract

A tunable energy-chirp compensator was used to remove a correlated energy chirp from the 60-MeV beam at the Brookhaven National Laboratory Accelerator Test Facility. The compensator operates through the interaction of the wakefield of the electron bunch with itself and consists of a planar structure comprised of two alumina bars with copper-plated backs separated by an adjustable beam aperture. By changing the gap size, the correlated energy chirp of the electron bunch was completely removed. Calculations show that this device, properly scaled to account for the electron bunch charge and length, can be used to remove residual correlated energy spread at the end of the linacs used for free-electron lasers. The experimental results are shown to be in good agreement with numerical simulations. Application of this technique can significantly simplify linac design and improve free-electron lasers performance.

Observation of a variable sub-THz radiation driven by a low energy electron beam from a thermionic rf electron gun

“…A similar structure can be efficiently utilized for other applications, e.g., for time-dependent beam diagnostics or to remove unwanted time-dependent energy variations in longitudinally compressed electron bunches using longer wavelengths [21][22][23][24][25].…”

Generation of Ramped Current Profiles in Relativistic Electron Beams Using Wakefields in Dielectric Structures

“…1 [14]. This method follows similar lines of recent work on dielectric structures used for beam and radiation manipulations, such as sources for narrowband THz radiation, beam dechirpers, and microbunchers [15][16][17]. For example, in the opposite limit, where the driver beam bunch length is much longer than the wakefield wavelength, the dielectric wakefield interaction can be used to produce micro-bunched beamlet distributions [18].…”

GHz laser-free time-resolved transmission electron microscopy: A stroboscopic high-duty-cycle method

“…Both mechanical shaping and/or electromagnetic manipulations of electron beams are common in the field of particle accelerators. They are used to tailor electron beam properties and for electron beam diagnostics, including emittance exchange experiments [11], phase-space imaging [12], energy-chirp compensation [13] and accelerator-based radiation sources [14,15]. Following previous reports on combined electromagnetic-mechanical GHz pulsers [8,16], the core component consists of a transverse deflecting cavity (TDC) and a chopping collimating aperture (CCA).…”