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https://doi.org/10.18429/JACoW-IPAC2015-TUPJE055
Title The Evolution of the Transverse Energy Distribution of Electrons from a GaAs Photocathode as a Function of its Degradation State
Authors
  • L.B. Jones, B.L. Militsyn, T.C.Q. Noakespresenter
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • H.E. Scheibler, A.S. Terekhov
    ISP, Novosibirsk, Russia
Abstract The brightness of a photoelectron injector is fundamentally limited by the mean longitudinal and transverse energy distributions of the photoelectrons emitted from its photocathode, and is increased significantly if the mean values of these quantities are reduced. To address this, ASTeC constructed a Transverse Energy Spread Spectrometer (TESS)* – an experimental facility designed to measure these transverse and longitudinal energy distributions which can be used for III-V semiconductor, alkali antimonide/telluride and metal photocathode research. We present measurements showing evolution of the transverse energy distribution of electrons from GaAs photocathodes as a function of their degradation state. Photocathodes were activated to negative electron affinity in our photocathode preparation facility (PPF)** with quantum efficiency around 10.5%. They were then transferred to TESS under XHV conditions, and progressively degraded through controlled exposure to oxygen. Data has been collected under photocathode illumination at 635 nm, and demonstrates a constant relationship between energy distribution and the level of electron affinity.
Footnotes & References * Proc. FEL ’13, TUPPS033, 290-293
** Proc. IPAC '10, TUPE095, 2347-2349, Proc. IPAC ’11, THPC129, 3185-3187
Paper download TUPJE055.PDF [0.757 MB / 4 pages]
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Conference IPAC2015, Richmond, VA, USA
Series International Particle Accelerator Conference (6th)
Proceedings Link to full IPAC2015 Proccedings
Session Tuesday Posters (Jefferson)
Date 05-May-15   16:00–18:00
Main Classification 2: Photon Sources and Electron Accelerators
Sub Classification T02 - Electron Sources
Keywords electron, detector, cathode, brightness, vacuum
Publisher JACoW, Geneva, Switzerland
Editors Stuart Henderson (ANL, Argonne, IL, USA); Evelyn Akers (Jlab, Newport News, VA, USA); Todd Satogata (JLab, Newport News, VA, USA); Volker R.W. Schaa (GSI, Darmstadt, Germany)
ISBN 978-3-95450-168-7
Published June 2015
Copyright
Copyright © 2015 by JACoW, Geneva, Switzerland     CC-BY Creative Commons License
cc Creative Commons Attribution 3.0