Thin-film Coating System for Alkali Antimonide Photocathode Performance Enhancement

Technical Report · Tue Dec 07 00:00:00 EST 2021

OSTI ID:1835593

Liu, Ao

Alkali antimonide photocathodes are commonly used in high-brightness photoinjectors because of their ultra-high quantum efficiency (QE) at green light wavelength, small thermal emittance and relative ease of growth. They have extremely stringent requirements on vacuum conditions and can be destroyed by even small amounts of residual gases in the system. Storing multiple alkali antimonides while maintaining their lifetime for continuous operation backups is eminently challenging and expensive. While researchers have realized that depositing a 2D thin-film on alkali antimonides provides encapsulation protections for the photocathode, applying the concept to real photoinjector applications needs demonstrations that the encapsulation can be introduced without damaging the integrity of the photocathode itself. Euclid, in collaboration with Brookhaven National Laboratory (BNL) are investigating an innovative approach to transfer the 2D thin-film onto a comparably less environmentally sensitive antimony substrate, and then form the photocathode through a process called “intercalation”, during which free alkali atoms “penetrate” the thin-film to react with the antimony (Sb) to form alkali antimonide. This process is technically more feasible but still requires significant amounts of work to demonstrate the mechanism of the full process.

• Research Organization: Euclid Techlabs LLC, Cleveland, OH (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: SC0021511
• OSTI ID: 1835593
• Type / Phase: SBIR (Phase I)
• Report Number(s): DOE – Euclid Techlabs – PH1 – DE-SC0021511; 21511
• Resource Relation: Related Information: All the reference papers are listed in the Phase I technical report.
• Country of Publication: United States
• Language: English