Figure 1: Experimental layout.
From: Demonstration of a positron beam-driven hollow channel plasma wakefield accelerator
The laser passes through the kinoform and is coupled to the beam axis by a gold mirror with a small central hole. Inset (a) shows the laser profile upstream of the lithium oven. A scintillating YAG screen 1.95 m downstream of plasma is used to measure the positron beam profile. Inset (b) shows the positron beam spatial profile as imaged on the YAG screen with the laser off and no plasma present. Inset (c) shows the beam profile with the laser on when the positron beam propagates through the plasma channel. The two profiles are similar, indicating that there are no net focusing forces because of the plasma channel. A scintillating Lanex screen downstream of the dipole measures the beam energy spectrum.
