Vasileios Georgiadis

We have developed dielectric-lined rectangular waveguide structures for terahertz (THz)-driven ultrafast deflection of 100 keV electron beams. The structures were designed to achieve THz phase velocity matching with co-propagating electron bunches. The phase-matching capability was experimentally confirmed through time-frequency analysis of the broadband coherent THz transmission measured by electro-optic sampling. The analysis determined both the frequency-dependent propagation constants in the electron interaction region and the propagation characteristics of the integrated THz tapered coupler.

The purpose of this study is to test whether concept mapping can be used for measuring the levels of number sense and use it to measure the mathematical experts’ level of number sense. The sample included 39 undergraduate and post-graduate students of Departments of Mathematics in Greece. A paper and pencil test was administered to measure the level of number sense in different mathematical domains. Additionally, the participants were asked to create a concept map with 1/2 as the central term. The results showed low levels of number sense with the majority of the participants responded in the number sense test by applying rules and algorithms rather than more holistic approaches that would indicate higher levels of number sense. Additionally, participants’ performance in concept mapping was strongly related to their performance in the number sense test. Specifically, participants with low number sense scores tended to present poor concept maps.

We report on the generation of a terahertz (THz) beam with a quasi-TEM 01 mode by exploiting the interferometric recombination of two linearly polarized emitters in a combined spintronic source. The generated THz beam was used to characterize the accelerating mode of a dielectric-lined waveguide (DLW) to inform on the recent demonstration of relativistic electron beam manipulation achieved with this THz-driven DLW at the CLARA research facility at Daresbury Laboratory.

We will present the first results from the CLARA research facility at Daresbury Laboratory demonstrating terahertz-driven acceleration of a relativistic 35 MeV electron beam. A polarization-tailored, frequency-tunable, narrowband terahertz source was used to directly excite the longitudinal accelerating mode of a dielectric-lined waveguide structure for collinear phase-velocity-matched THz-electron interaction.

We report on the transmission properties of a single-cycle terahertz pulse through a rectangular-shape dielectric-lined waveguide designed for terahertz-driven manipulation of 100 keV electrons.