| AVS 57th International Symposium & Exhibition | |
| Vacuum Technology | Wednesday Sessions |
| Session VT-WeM |
| Session: | Accelerators, Large Vacuum Systems, and Vacuum Surfaces |
| Presenter: | M. Nishiwaki, KEK-High Energy Accelerator Research Organization, Japan |
| Authors: | S. Kato, KEK-High Energy Accelerator Research Organization, Japan M. Nishiwaki, KEK-High Energy Accelerator Research Organization, Japan V. Chouhan, KEK-High Energy Accelerator Research Organization, Japan P.V. Tyagi, KEK-High Energy Accelerator Research Organization, Japan T. Noguchi, KEK-High Energy Accelerator Research Organization, Japan |
| Correspondent: | Click to Email |
It is mandatory to investigate field emission on Nb SRF cavity systematically since strong field emission often limits the cavity performance. The field emission strength and the number of emission sites strongly depend on Nb surface properties which are determined by its surface treatment and handling. Field emission scanner developed allows us to measure a distribution of the field emitting sites over a sample surface at a given field strength along with its FE-SEM (field emission scanning electron microscope) observation and energy dispersive x-ray analysis. The field emission scanner consists of a sample stage driven by piezo actuators and an anode needle driven by precise 3D stepping motors. In addition, this system was newly equipped with a sample load-lock system for existing UHV suitcases. The compact scanner was installed into the space between the object lens and the SEM sample holder. The UHV pumps were additionally installed in order to improve the base pressure down to UHV to reduce adsorbates during the measurement. This article describes development of the field emission scanner and its preliminary results of the application to niobium samples.