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Title: Quantum efficiency enhancement in CsI/metal photocathodes

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Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
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Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Chemical Physics Letters
Additional Journal Information:
Journal Volume: 621; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-05-10 09:08:46; Journal ID: ISSN 0009-2614
Country of Publication:

Citation Formats

Kong, Lingmei, Joly, Alan G., Droubay, Timothy C., and Hess, Wayne P. Quantum efficiency enhancement in CsI/metal photocathodes. Netherlands: N. p., 2015. Web. doi:10.1016/j.cplett.2015.01.010.
Kong, Lingmei, Joly, Alan G., Droubay, Timothy C., & Hess, Wayne P. Quantum efficiency enhancement in CsI/metal photocathodes. Netherlands. doi:10.1016/j.cplett.2015.01.010.
Kong, Lingmei, Joly, Alan G., Droubay, Timothy C., and Hess, Wayne P. 2015. "Quantum efficiency enhancement in CsI/metal photocathodes". Netherlands. doi:10.1016/j.cplett.2015.01.010.
title = {Quantum efficiency enhancement in CsI/metal photocathodes},
author = {Kong, Lingmei and Joly, Alan G. and Droubay, Timothy C. and Hess, Wayne P.},
abstractNote = {},
doi = {10.1016/j.cplett.2015.01.010},
journal = {Chemical Physics Letters},
number = C,
volume = 621,
place = {Netherlands},
year = 2015,
month = 2

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.cplett.2015.01.010

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Cited by: 1work
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  • High quantum efficiency enhancement is found for hybrid metal-insulator photocathodes consisting of thin films of CsI deposited on Cu(100), Ag(100), Au(111) and Au films irradiated by 266 nm laser pulses. Low work functions (near or below 2 eV) are observed following ultraviolet laser activation. Work functions are reduced by roughly 3 eV from that of clean metal surfaces. We discuss various mechanisms of quantum efficiency enhancement for alkali halide/metal photocathode systems and conclude that the large change in work function, due to Cs accumulation of Cs metal at the metal-alkali halide interface, is the dominant mechanism for quantum efficiency enhancement
  • Modern electron beams have demonstrated the brilliance needed to drive free electron lasers at x-ray wavelengths, with the principle improvements occurring since the invention of the photocathode gun. The state-of-the-art normalized emittance electron beams are now becoming limited by the thermal emittance of the cathode. In both DC and RF photocathode guns, details of the cathode emission physics strongly influence the quantum efficiency and the thermal emittance. Therefore improving cathode performance is essential to increasing the brightness of beams. It is especially important to understand the fundamentals of cathode quantum efficiency and thermal emittance. This paper investigates the relationship betweenmore » the quantum efficiency and the thermal emittance of metal cathodes using the Fermi-Dirac model for the electron distribution. We derive the thermal emittance and its relationship to the quantum efficiency, and compare our results to those of others.« less
  • The quantum efficiency of gold photocathodes has been investigated by using synchrotron radiation from 2--8 keV; in particular its detailed structure near the M absorption edge region is obtained. The secondary electron conversion efficiency of gold has been calculated by using the mass absorption coefficient given by a relativistic Hartree-Slater model and by the semiempirical values of Henke et al., respectively. These data are compared with the published data at some discrete energies, and we add several new data points, especially for the gold M edge region (2--4 keV). X-ray absorption fine structure (EXAFS) has been observed in the secondarymore » electron current of the gold photocathode as well as in the detection current responses of a microchannel plate and a silicon surface barrier detector.« less
  • We have measured the quantum efficiency for normal incidence radiation of microchannel plate detectors which use opaque or semitransparent photocathodes made of fluffy CsI, solid CsI, or both. At wavelengths below --44 A-circle, detectors with fluffy CsI semitransparant photocathodes are more efficient than those with opaque photocathodes of silid CsI, but the opposite is true at longer wavelengths. Fluffy CsI semitransparent photocathodes with surface densities between 150 and 400 2/ are optimum at soft x-ray wavelengths, and we have obtained efficiencies of 35 and 41% at 8 and 44A-circle, respectively, for a single-layer photocathode. The measured peak efficiency formore » an opaque layer of solid CsI, deposited at O/sup 0/ coating angle and 5000 A-circle (226 ..-->..g/cm/sub 2/) in thickness, is 56% at 110 A-circle.« less