Upgrades of the Experimental Setup for Electron Beam Self-modulation Studies at PITZ.

The self-modulation instability is fundamental for the plasma wakefield acceleration experiment of the AWAKE collaboration at CERN where this effect is supposed to be used to generate proton bunches short enough for producing high acceleration fields. For ease of experimentation it was decided to set up a supporting experiment at the electron accelerator PITZ (Photo Injector Test facility at DESY, Zeuthen site), given that the underlying physics is the same. The goals are to demonstrate and investigate in detail the self-modulation of long electron beams. In 2015 a first set of experiments was conducted utilizing as key elements a novel cross-shaped lithium plasma cell and an ArF excimer laser for plasma generation. No self-modulation was observed yet because of various experimental shortcomings. The properties of the experimental setup were studied in detail and in this contribution we report about the upgrades which are projected to enable the observation of the self-modulation in the upcoming experimental run