SRF2013 - List of Authors (Noguchi, T.)

Paper	Title	Page
TUP108	Study on Niobium Scratch and Tantalum or Carbonaceous Contamination at Niobium Surface with Field Emission Scanner	731
	S. Kato, H. Hayano, T. Kubo, T. Noguchi, T. Saeki, M. Sawabe KEK, Ibaraki, Japan
	It is mandatory to investigate field emission from niobium SRF cavity surface systematically since even small field emission often limits the cavity performance terribly. The field emission strength and the number of emission sites strongly depend on niobium surface properties which are determined by its surface treatment and handling. It was found that carbonaceous contamination including carbon, oxygen, sometimes, nitrogen often segregates at CPed or EPed surface with a size of several micron to several tens of micron-meters. There is a strong doubt that this contamination causes field emission from the surface. Newly developed field emission scanner (FES) allows us to measure a distribution of the field emitting sites over a sample surface at a given field strength along with its SEM (scanning electron microscope) observation and EDX (energy dispersive x-ray) analysis. This article describes results of the FES-SEM-EDX application to carbonaceous contamination at niobium surface.

Paper

Title

Page

Study on Niobium Scratch and Tantalum or Carbonaceous Contamination at Niobium Surface with Field Emission Scanner

731

S. Kato, H. Hayano, T. Kubo, T. Noguchi, T. Saeki, M. Sawabe
KEK, Ibaraki, Japan

It is mandatory to investigate field emission from niobium SRF cavity surface systematically since even small field emission often limits the cavity performance terribly. The field emission strength and the number of emission sites strongly depend on niobium surface properties which are determined by its surface treatment and handling. It was found that carbonaceous contamination including carbon, oxygen, sometimes, nitrogen often segregates at CPed or EPed surface with a size of several micron to several tens of micron-meters. There is a strong doubt that this contamination causes field emission from the surface. Newly developed field emission scanner (FES) allows us to measure a distribution of the field emitting sites over a sample surface at a given field strength along with its SEM (scanning electron microscope) observation and EDX (energy dispersive x-ray) analysis. This article describes results of the FES-SEM-EDX application to carbonaceous contamination at niobium surface.