Cold electron beams from cryo-cooled, alkali antimonide photocathodes

Abstract

In this letter we report on the generation of cold electron beams using a Cs3Sb photocathode grown by co-deposition of Sb and Cs. By cooling the photocathode to 90 K we demonstrate a significant reduction in the mean transverse energy validating the long standing speculation that the lattice temperature contribution limits the mean transverse energy or thermal emittance near the photoemission threshold, opening new frontiers in generating ultra-bright beams. At 90 K, we achieve a record low thermal emittance of 0.2 $\mu$m (rms) per mm of laser spot diameter from an ultrafast (sub-picosecond) photocathode with quantum efficiency greater than $7\times 10^{-5}$ using a visible laser wavelength of 690 nm.

References in corpus (3)

• New electron source concept for single-shot sub-100 fs electron diffraction in the 100 keV range
• Demonstration of Cathode Emittance Dominated High Bunch Charge Beams in a DC gun-based Photoinjector
• Fundamental Photoemission Brightness Limit from Disorder Induced Heating

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• Multi-objective Optimizations of a Novel Cryo-cooled DC Gun Based Ultra Fast Electron Diffraction Beamline
• The Role of Low Intrinsic Emittance in Modern Photoinjector Brightness
• Electronic structure and optical properties of Na${}_2$KSb and NaK${}_2$Sb from first-principles many-body theory
• Lossless monochromation for electron microscopy with pulsed photoemission sources and rf cavities
• Atomically smooth films of CsSb: a chemically robust visible light photocathode
• Design of a High-bunch-charge 112-MHz Superconducting RF Photoemission Electron Source
• Rapid thermal emittance and quantum efficiency mapping of a cesium telluride cathode in an rf photoinjector using multiple laser beamlets
• Femtosecond Mega-electron-volt Electron Energy-Loss Spectroscopy
• Ab initio many-body photoemission theory of transverse energy distribution of photoelectrons: PbTe(111) as a case study with experimental comparisons
• Franck-Condon electron emission from polar semiconductor photocathodes
• Ultrafast Electron Diffraction: Visualizing Dynamic States of Matter