WE3A5
DESY Zeuthen, Zeuthen, Germany
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
INFN/LASA, Segrate (MI), Italy
Università degli Studi di Milano & INFN, Segrate, Italy
Multi-alkali antimonide photocathodes can have high quantum efficiency similar to UV-sensitive (Cs₂Te) photocathodes but with the advantages of photoemission sensitivity in the green wavelength and a significant reduction in the mean transverse energy of photoelectrons. In order to optimize and better understand the photo emissive film properties of K-Cs-Sb photocathodes, a batch of two photocathodes with different thicknesses was grown on molybdenum substrates via a sequential deposition method in a new preparation system at INFN LASA. During the deposition, a "multi-wavelengths" diagnostic, i.e., the measurements of the real-time photocurrent and reflectivity at different wavelengths, has been applied during the photocathode film growth. In addition, in the framework of density functional theory (DFT), we investigated the electronic and optical properties of K{2}CsSb material. This allowed us to establish a correlation between the calculated and measured optical properties, such as reflectivity. In this report, we present and discuss the experimental results obtained from the two different thickness K{2}CsSb photocathodes, along with the DFT results of K{2}CsSb material.
