Low emittance design of the electron gun and the focusing channel of the Compact Linear Collider drive beam

For the Compact Linear Collider project at CERN, the power for the main linacs is extracted from a drive beam generated from a high current electron source. The design of the electron source and its subsequent focusing channel has a great impact on the beam dynamic considerations of the drive beam. We report the design of a thermionic electron source and the subsequent focusing channels with the goal of production of a high quality beam with a very small emittance

An analytical approach for beam loading compensation and excitation of maximum cavity field gradient in a coupled cavity-waveguide system

The critical process of beam loading compensation in high intensity accelerators brings under control the undesired effect of the beam induced fields to the accelerating structures. A new analytical approach for optimizing standing wave accelerating structures is found which is hugely fast and agrees very well with simulations. A perturbative analysis of cavity and waveguide excitation based on the Bethe theorem and normal mode expansion is developed to compensate the beam loading effect and excite the maximum field gradient in the cavity. The method provides the optimum values for the coupling factor and the cavity detuning. While the approach is very accurate and agrees well with simulation software, it massively shortens the calculation time compared with the simulation software

Design study of the electron beamline, and the beam optimization for the AWAKE RUN 2 experiment at CERN

Demonstration of the electron acceleration through the proton beam-driven plasma wakefield has been successfully done by the AWAKE RUN 1 experiment. Moreover, next AWAKE experiment is scheduled. Main goal of the AWAKE RUN 2 experiment is to achieve the capturing efficiency and the energy gain over 90%, and 10 GeV. In order to accomplish the goal, beam size, and its length have to be less than 50 μm, and 100 fs rms, respectively. Since the conventional beamline cannot meet the AWAKE RUN 2 requirements, we are focusing on designing new type of the electron beamline. In this paper, we present simulation results of the beam size, and the bunch length along the new beamline

The electron accelerators for the AWAKE experiment at CERN—Baseline and Future Developments

The AWAKE collaboration prepares a proton driven plasma wakefield acceleration experiment using the SPS beam at CERN. A long proton bunch extracted from the SPS interacts with a high power laser and a 10 m long rubidium vapor plasma cell to create strong wakefields allowing sustained electron acceleration. The electron beam to probe these wakefields is created by an electron accelerator consisting of an rf-gun and a booster structure. This electron source should provide beams with intensities between 0.1 and 1 nC, bunch lengths between 0.3 and 3 ps and an emittance of the order of 2 mm mrad. The booster structure should accelerate the electrons to 16 MeV. The electron line includes a series of diagnostics (pepper-pot, BPMs, spectrometer, Faraday cup and screens) and an optical transfer line merges the electron beam with the proton beam on the same axis. The installation of the electron line started in early 2017 and the commissioning will take place at the end of 2017. The first phase of operation is called RUN1. After the long shutdown of LHC a second phase for AWAKE is planned starting 2021 called RUN2. In this phase the aim is to demonstrate the acceleration of high quality electron beams therefore a bunch length of the order of 100 fs rms is required corresponding to a fraction of the plasma wavelength. The AWAKE collaboration is studying the design of such an injector either based on classical rf-gun injectors or on laser wake-field acceleration. The focus for the RF accelerator is on a hybrid design using an S-band rf-gun and x-band bunching and acceleration cavities. The layout of the current and the future electron accelerator and transfer line, including the diagnostics will be presented