Alkali-antimonide photocathodes were grown on Si(100) and studied by means of XPS and UHV-AFM to validate the growth procedure and morphology of this material. The elements were evaporated sequentially at elevated substrate temperatures (first Sb, second K, third Cs). The generated intermediate K-Sb compound itself is a photocathode and the composition of K2.4Sb is close to the favored K3Sb stoichiometry. After cesium deposition, the surface layer is cesium enriched. The determined rms roughness of 25 nm results in a roughness domination of the emittance in the photoinjector already above 3 MV/m

We present the results of our investigation of lead as a suitable photocathode material for superconducting rf injectors. Quantum efficiencies (QE) have been measured for a range of incident photon energies and compared to predictions from the three-step model of photoemission. A variety of cathode preparation methods have been used, including various lead plating techniques on a niobium substrate. The effects of operating at ambient and cryogenic temperatures and different vacuum levels on the cathode QE have also been studied.

This paper presents an overview of existing and emerging technologies on electron sources that can service various energy recovering linacs under consideration. Photocathodes that can deliver average currents from 1 mA to 1 A, the pros and cons associated with these cathodes are addressed. Status of emerging technologies such as secondary emitters, cesiated dispenser cathodes, field and photon assisted field emitters and super lattice photocathodes are also reviewed. r

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This work presents an investigation of the photoemission properties of niobium. The quantum efficiency (QE) of niobium cathodes was measured for a variety of surface preparations relevant to the operation of a superconducting injector. The dependence of the QE on wavelength, applied field, and laser cleaning energy was determined. The three-step model of photoemission was adapted to fit the observed emission behavior. QE values of 6.5×10−5 for 266 nm, 1.0×10−4 for 248 nm, and 2.8×10−4 for 193 nm were observed with a bias field of 1MV∕m.