Surface Characterization and Field Emission Measurements of Copper Samples inside a Scanning Electron Microscope

Vacuum breakdown in normal-conducting accelerating structures is a limiting factor for high gradient acceleration. Many aspects of the physics governing the breakdown process and its onset are yet to be fully understood. At Uppsala University we address these questions with an in-situ experimental setup mounted in an environmental scanning electron microscope. It consists of a piezo motor driven tungsten needle and a sample surface mounted on a piezo stage, allowing for nano-meter 3D-position control. One of the piezo motors controls the needle-sample gap while the two other scan across the surface. A DC-voltage up to 1 kV is applied across the gap and field emission currents from a copper surface are measured with an electrometer. Here we present the setup and some initial results.