Speakers
Description
Plasma-based accelerators that impart energy gain as high as several GeV to electrons or positrons within a few centimeters have engendered a new class of diagnostic techniques very different from those used in connection with conventional radio-frequency (rf) accelerators [1]. The need for new diagnostics stems from the micrometer scale and transient structure of plasma accelerators, and from the micrometer source size, small normalized transverse emittance (εn < 0.1 mm mrad) and ultrashort duration (τb ∼ 1 fs) of plasma-accelerated e-bunches, compared to those from RF linacs. Prof. Downer will first review single-shot diagnostics that the plasma accelerator community has developed to determine such small εn and τb noninvasively from measuring electromagnetic radiation from THz to X-rays that the electrons emit. Dr. LaBerge will then feature recent experimental results [2, 3] that measure the internal coherent nanostructure of plasma-accelerated e-bunches in a single shot by analyzing their coherent optical transition radiation over a wide spectral range.
[1] M. C. Downer, R. Zgadzaj, A. Debus, U. Schramm, and M. C. Kaluza, “Diagnostics for plasma-based electron accelerators,” Rev. Mod. Phys. 90, (2018).
[2] A. H. Lumpkin, M. LaBerge, et al., “Coherent optical emittance evaluations of microbunched electron beamlets from laser-driven plasma accelerators,” Phys. Rev. Lett. 125, 014801 (2020).
[3] M. LaBerge et al., "Coherent 3D microstructure of plasma-wakefield-accelerated e-bunches," in preparation (2023).
