Preparations for a plasma wakefield acceleration (PWA) experiment at PITZ

Abstract

Self-modulation of particle beams in a plasma was proposed as a new concept to enable plasma wakefield acceleration with long driver beams. An experiment is in preparation at the Photo Injector Test facility at DESY, Zeuthen site (PITZ), to demonstrate and characterize self-modulation of an electron beam. Key elements for this are the highly flexible photocathode laser system and the well-developed beam diagnostics. Preparations for the experiment have started at PITZ. In a first step a suitable insertion point for the plasma cell was determined with beam dynamics simulations. It was decided to use laser ionization to generate the plasma since this technique is capable of providing a homogeneous plasma channel with sufficient size (1 mm diameter, 60 mm length) and density (10 15 cm −3 ). Two different ways were found to generate the plasma, utilizing either field ionization with a 1 T W Ti:Sapphire laser or single photon ionization with a 400 mJ ArF excimer laser. As opposed to previously realized designs the ionization laser is coupled from the side, orthogonally to the electron beam direction.

First results of the plasma wakefield acceleration experiment at PITZ

“…Calculations show [15] that about a few hundred mJ pulse energy laser is needed to achieve about 10 15 cm À 3 plasma density. The laser light travels from the optical lab down to the PITZ tunnel via a specially built laser beamline.…”

Multi-proton bunch driven hollow plasma wakefield acceleration in the nonlinear regime

“…The AWAKE experiment at CERN [25][26][27][28] follows this concept and is the world's first proof-of-principle experiment of long proton bunch driven PWFA. Several related experiments with long or pre-bunched electron beams [29][30][31][32][33][34][35] are proposed or conducted to enhance the understandings of the SMI and resonantly driven waves.…”

Electron trapping and acceleration by the plasma wakefield of a self-modulating proton beam

“…The experiment named AWAKE thus started at CERN, 1,[12][13][14] as well as several supporting experiments with electron beams. [15][16][17][18][19] Injection of electrons into the wakefield of a selfmodulating beam turned out to be a nontrivial task. During development of the self-modulation instability, the phase velocity of the wakefield is substantially lower than the light velocity c, as was pointed out in Refs.…”