Advanced metal alloy systems for massive high-current photocathodes

Ткаченко, В. Г.; Kondrashev, A. I.; Maksimchuk, I. N.

doi:10.1007/s00340-009-3887-z

Cited by 17 publications

(8 citation statements)

References 28 publications

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“…6, is on the order of 10 À5 . These are typical results for metallic photocathodes [17][18][19]. Assuming that the charge emission is in concert with the laser pulse width, the duration of the charge emission at the cathode is…”

Section: A Charge Emission and Quantum Efficiencysupporting

confidence: 53%

Towards high brightness electron beams from multifilamentaryNb3Snwire photocathode

Ardana-Lamas

Pimpec

Anghel

et al. 2013

Phys. Rev. ST Accel. Beams

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In order to find electron sources of low emittance and high quantum efficiency, single tip cathodes with a microstructured surface are investigated. Emission currents up to 310 A were obtained, by combining a 2 ns, 50 kV accelerating voltage pulse with a 266 nm wavelength, picosecond ( t ¼ 6:2 ps) laser delivering a few J pulse energy. The multifilamentary cylindric Nb 3 Sn tip with a typical diameter of 0.8 mm provides quantum efficiencies up to 0.5%. The microstructured needle has also been tested in a combined diode-rf electron gun with 500 kV, 250 ns pulsed bias voltage as a first step towards reducing emittance-spoiling space-charge forces.

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Section: A Charge Emission and Quantum Efficiencysupporting

confidence: 53%

Towards high brightness electron beams from multifilamentaryNb3Snwire photocathode

Ardana-Lamas

Pimpec

Anghel

et al. 2013

Phys. Rev. ST Accel. Beams

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“…Nevertheless, the challenge to obtain future x-ray FELs requires further improvements of the quality of the electron beams. Many laboratories are interested in R&D on photocathodes to find new materials capable of producing bright electron beams for the next FEL sources [5][6][7][8][9][10]. A good cathode is characterized by high robustness, promptness of emission, high quantum efficiency (QE), and low thermal emittance.…”

Section: Introductionmentioning

confidence: 99%

Highlights on photocathodes based on thin films prepared by pulsed laser deposition

Lorusso

Gontad

Perrone

et al. 2011

Phys. Rev. ST Accel. Beams

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We review the current status of metallic photocathodes based on thin films prepared by pulsed laser deposition (PLD) and we explore ways to improve the performance of these devices. PLD seems to be a very efficient and suitable technique for producing adherent and uniform thin films. Time-resolved mass spectrometric investigations definitively suggest that the deposition of high-purity metallic thin films should be carried out in ultrahigh vacuum systems and after a deep and careful laser cleaning of the target surface. Moreover, the laser cleaning of the target surface is highly recommended not only to remove the first contaminated layers but also to improve the quality of the vacuum by reducing the partial pressure of reactive chemical species as H 2 O, H 2 , and O 2 molecules. The challenge to realize high-purity Mg and Y thin films is very interesting for the photocathode R&D due to the good photoemission properties of these metals. Photocathodes based on Mg and Y thin films have been characterized by scanning electron microscopy and x-ray diffraction techniques to derive the morphological and structural features, respectively. They were also tested in a photodiode cell to deduce the photoelectron properties. The quantum efficiency of such photocathodes was systematically improved by in situ laser cleaning treatments of the surface in order to remove the contaminated layers reaching, in this way, the quantum efficiency of the corresponding bulk materials.

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“…The clustering in the structure of substitutional solid solutions shifts the optical absorption maximum in the UV spectral range owing to the growth in the electron density of states near the Fermi energy level. This conclusion is confirmed by researches of the spectral sensitivity of the photoemission quantum yield from metal alloys containing a high concentration of clustered compounds Mg Ba and, in such a way, providing a record packing density (up to 10 14 -10 16 m −2 ) for the sources of optical excitation (nanoemitters) [24]. If the concentration of such nanoclusters reaches a value of 5 × 10 14 m −2 , the low photoemission quantum yield typical of nominally pure metals (Mg, Al, Cu) becomes larger by two to three orders of magnitude.…”

Section: Short-range Clustered Compoundsmentioning

confidence: 53%

Features of the Formation of Cluster Compounds in Metal Solid Solutions

Abramov

Ткаченко

2017

Ukr. J. Phys.

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Physical origins of the chemical (energy) shifting of Auger electron lines in the spectra of Al-Li, Ba (by 1.4 eV) and Mg-Ba (by 2 eV) systems containing cluster-forming alloying elements such as barium have been discussed. The observed peaks are associated with the formation of Al18Ba9 and Mg16Ba2 cluster compounds characterized by their own electron configurations.K e y w o r d s: cluster compounds, Auger electron spectrum, chemical (energy) shifts.

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Advanced metal alloy systems for massive high-current photocathodes

Cited by 17 publications

References 28 publications

Towards high brightness electron beams from multifilamentaryNb3Snwire photocathode

Towards high brightness electron beams from multifilamentaryNb3Snwire photocathode

Highlights on photocathodes based on thin films prepared by pulsed laser deposition

Features of the Formation of Cluster Compounds in Metal Solid Solutions

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