Ultrafast laser pulse heating of metallic photocathodes and its contribution to intrinsic emittance

J. Maxson, P. Musumeci, L. Cultrera, S. Karkare, H. Padmore

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

The heating of the electronic distribution of a copper photocathode due to an intense drive laser pulse is calculated under the two-temperature model using fluences and pulse lengths typical in RF photoinjector operation. Using the finite temperature-extended relations for the photocathode intrinsic emittance and quantum efficiency, the time-dependent emittance growth due to the same photoemission laser pulse is calculated. This laser heating is seen to limit the intrinsic emittance achievable for photoinjectors using short laser pulses and low quantum efficiency metal photocathodes. A pump-probe photocathode experiment in a standard 1.6 cell S-band gun is proposed, in which simulations show the time dependent thermal emittance modulation within the bunch from laser heating can persist for meters downstream and, in principle, be measured using a slice emittance diagnostic.

Original languageEnglish (US)
Pages (from-to)99-104
Number of pages6
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume865
DOIs
StatePublished - Sep 1 2017
Externally publishedYes

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Keywords

  • Photocathodes
  • Photoinjectors
  • Ultrafast heating

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation

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