CTR Diagnostics for Laser Produced Electron Beams in MG Magnetic Fields Generated by the 1 Ma Pulsed Power Machine

The Zebra pulsed power generator routinely produces longitudinal and transverse magnetic fields of 1-3 MG. The 1 MA Zebra machine coupled with a 50 TW Leopard laser will be used to conduct experiments for the collimation of fast electron in solid targets by external magnetic fields. Guiding of fast electrons is important for the fast ignition concept for ICF, particle accelerators, and medical application. Coherent transition radiation (CTR) diagnostics indicates a shape of the beam of fast electrons on the rear side of the target. CTR is generated when a modulated electron beam crosses the boundary of the refractive index. Modulations are a result of the laser’s oscillating electric field. CTR is generated on the backside of Si and CH targets at laser intensity of ~10 19 W/cm 2 . Targets will be placed in the axial magnetic field generated in coil loads by the Zebra pulsed power machine. A high resolution CTR beampass was developed. Spatial resolution of the beampass was improved from 9 μm resolution to 2 μm, this is capable of imaging of the fine structure of electron beam filamentation. To accommodate for the new diagnostic a new style current return cage was also built and tested.