Intrinsic emittance reduction in transmission mode photocathodes

High quantum efficiency (QE) and low emittance electron beams provided by multi-alkali photocathodes make them of great interest for next generation high brightness photoinjectors. Spicer's three-step model well describes the photoemission process; however, some photocathode characteristics suc...

Full description

Saved in:
Bibliographic Details
Published in:Applied physics letters 2016-03, Vol.108 (12)
Main Authors: Lee, Hyeri, Cultrera, Luca, Bazarov, Ivan
Format: Article
Language:English
Subjects:
Applied physics
Brightness
CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
electromagnetic coils
Electron beams
electron gas
Electrons
Emittance
glass
Glass substrates
Inelastic scattering
leptons
MATERIALS SCIENCE
Monte Carlo methods
phonon scattering
Photocathodes
Photoelectric emission
Quantum efficiency
Reduction
Reflection
semiconductors
ultrafast electron diffraction
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:High quantum efficiency (QE) and low emittance electron beams provided by multi-alkali photocathodes make them of great interest for next generation high brightness photoinjectors. Spicer's three-step model well describes the photoemission process; however, some photocathode characteristics such as their thickness have not yet been completely exploited to further improve the brightness of the generated electron beams. In this work, we report on the emittance and QE of a multi-alkali photocathode grown onto a glass substrate operated in transmission and reflection modes at different photon energies. We observed a 20% reduction in the intrinsic emittance from the reflection to the transmission mode operation. This observation can be explained by inelastic electron-phonon scattering during electrons' transit towards the cathode surface. Due to this effect, we predict that thicker photocathode layers will further reduce the intrinsic emittance of electron beams generated by photocathodes operated in transmission mode.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4944790