Speaker
Description
As accelerators and electron microscopes become more advancement, high-performance photocathodes are required. In particular, CsK2Sb photocathode is of interest because of its low emittance, excitability in visible light, and high quantum efficiency (QE). On the other hand, it has drawbacks such as weak structure, limited operating vacuum pressure, and short lifetime with time or charge. To resolve these issues, it is necessary to understand the molecular structure of the cathode and its degradation mechanism. In this study, we transported CsK2Sb photocathode to a beamline of synchrotron radiation facility using a vacuum transport system for surface analysis. Specifically, the cathode was deposited at the evaporation system at Nagoya University. We transported it to Aichi Synchrotron Radiation Center (Aichi SR) away from 15 km, and analyzed it in the depth direction by X-ray photoelectron spectroscopy (XPS) at BL7U. Based on the results, we quantitatively evaluated the composition ratios and stoichiometry of the cathode element (Sb, K, Cs). A Cs excess state was observed at the surface, and it is consistent with previous studies. It was observed that K was first desorbed among the three elements of cathode with sputtering. The cause is considered that weakest binding energy of K.
Funding Agency
This work is partly supported by Grants-in-Aid for Scientific Research (Grant-in-Aid for Young Scientists, 21K17994).
| I have read and accept the Privacy Policy Statement | Yes |
|---|
