Gigahertz repetition rate thermionic electron gun concept

\u3cp\u3eWe present a novel concept for the generation of gigahertz repetition rate high brightness electron bunches. A custom design 100 kV thermionic gun provides a continuous electron beam, with the current determined by the filament size and temperature. A 1 GHz rectangular rf cavity deflects the beam across a knife-edge, creating a pulsed beam. Adding a higher harmonic mode to this cavity results in a flattened magnetic field profile which increases the duty cycle to 30%. Finally, a compression cavity induces a negative longitudinal velocity-time chirp in a bunch, initiating ballistic compression. Adding a higher harmonic mode to this cavity increases the linearity of this chirp and thus decreases the final bunch length. Charged particle simulations show that with a 0.15 mm radius LaB6 filament held at 1760 K, this method can create 279 fs, 3.0 pC electron bunches with a radial rms core emittance of 0.089 mm mrad at a repetition rate of 1 GHz.\u3c/p\u3

EuroLEAP; European Laser Electron controlled Acceleration in Plasmas to GeV energy range

No abstract

Theory and particle tracking simulations of a resonant radiofrequency deflection cavity in TM110 mode for ultrafast electron microscopy

We present a theoretical description of resonant radiofrequency (RF) deflecting cavities in TM 110 mode as dynamic optical elements for ultrafast electron microscopy. We first derive the optical transfer matrix of an ideal pillbox cavity and use a Courant-Snyder formalism to calculate the 6D phase space propagation of a Gaussian electron distribution through the cavity. We derive closed, analytic expressions for the increase in transverse emittance and energy spread of the electron distribution. We demonstrate that for the special case of a beam focused in the center of the cavity, the low emittance and low energy spread of a high quality beam can be maintained, which allows high-repetition rate, ultrafast electron microscopy with 100 fs temporal resolution combined with the atomic resolution of a high-end TEM. This is confirmed by charged particle tracking simulations using a realistic cavity geometry, including fringe fields at the cavity entrance and exit apertures.

The CompactLight Design Study

Abstract CompactLight is a Design Study funded by the European Union under the Horizon 2020 research and innovation funding programme, with Grant Agreement No. 777431. CompactLight was conducted by an International Collaboration of 23 international laboratories and academic institutions, three private companies, and five third parties. The project, which started in January 2018 with a duration of 48 months, aimed to design an innovative, compact, and cost-effective hard X-ray FEL facility complemented by a soft X-ray source to pave the road for future compact accelerator-based facilities. The result is an accelerator that can be operated at up to 1 kHz pulse repetition rate, beyond today’s state of the art, using the latest concepts for high brightness electron photoinjectors, very high gradient accelerating structures in X-band, and novel short-period undulators. In this report, we summarize the main deliverable of the project: the CompactLight Conceptual Design Report, which overviews the current status of the design and addresses the main technological challenges

The CompactLight Design Study

CompactLight is a Design Study funded by the European Union under theHorizon 2020 research and innovation funding programme, with Grant Agreement No. 777431.CompactLight was conducted by an International Collaboration of 23 internationallaboratories and academic institutions, three private companies, and five third parties.The project, which started in January 2018 with a duration of 48 months, aimed to designan innovative, compact, and cost-effective hard X-ray FEL facility complemented by asoft X-ray source to pave the road for future compact accelerator-based facilities. Theresult is an accelerator that can be operated at up to 1 kHz pulse repetition rate,beyond today’s state of the art, using the latest concepts for high brightness electronphotoinjectors, very high gradient accelerating structures in X-band, and novelshort-period undulators. In this report, we summarize the main deliverable of theproject: the CompactLight Conceptual Design Report, which overviews the current statusof the design and addresses the main technological challenges