IPAC2015 - Table of Session: WEAD (Contributed Orals (MC3))

Paper	Title	Page
WEAD1	Commissioning and Recent Experimental Results at the Argonne Wakefield Accelerator Facility (AWA)	2472
	M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, J.H. Shao, D. Wang, C. Whiteford, E.E. Wisniewski ANL, Argonne, Illinois, USA S.P. Antipov, C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA G. Ha POSTECH, Pohang, Kyungbuk, Republic of Korea J.H. Shao, D. Wang TUB, Beijing, People's Republic of China
	Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357. The commissioning of the upgraded AWA facility has been recently completed. The L-band electron gun has been fully commissioned and has been successfully operated with its Cesium Telluride photocathode at a gradient of 80 MV/m. Single bunches of up to 100 nC, and bunch trains of up to 32 bunches have been generated. The six new pi-mode accelerating cavities bring the beam energy to 75 MeV. Initial measurements of the beam parameters have been performed. This intense beam has been used to drive high gradient wakefields in several structures. A second beamline provides electron bunches to probe the wakefields generated by the intense drive beam. One of the main goals of the facility is to generate short RF pulses with GW power levels, corresponding to accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure.
	Slides WEAD1 [2.091 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEAD1
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WEAD2	Experimental Results of Carbon NanoTube Cathodes inside RF Environment	2475
	L. Faillace, S. Boucher, J.J. Hartzell, A.Y. Murokh RadiaBeam, Santa Monica, California, USA D. Mihalcea, P. Piot, J.C.T. Thangaraj Fermilab, Batavia, Illinois, USA H. Panuganti Northern Illinois University, DeKalb, Illinois, USA
	Funding: Work supported by US DOE SBIR grant # DE-SC0004459 Carbon Nano Tubes (CNT’s) as field-emitters have been investigated for more than two decades and can produce relatively low emittance electron beams for a given cathode size. Unlike thermionic cathodes, CNT cathodes are able to produce electrons at room temperature and relatively low electric field (a few MV/m). In collaboration with FermiLab, we have recently tested CNT cathodes both with DC and RF fields. We observed a beam current close to 1A with a ~1cm² CNT cathode inside an L-band RF gun. Steady operation was obtained up to 650 mA and the measured current vs. surface field plot showed perfect agreement with the Fowler-Nordheim distribution.
	Slides WEAD2 [10.445 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEAD2
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEAD3	Quantum Efficiency Improvement of Polarized Electron Source using Strain Compensated Super Lattice Photocathode	2479
	N. Yamamoto, M. Hosaka, A. Mano, T. Miyauchi, Y. Takashima, Y. Takeda Nagoya University, Nagoya, Japan X.J. Jin, M. Yamamoto KEK, Ibaraki, Japan
	Polarized electron beam is essential for future electron-positron colliders and electron-ion colliders. Improving the quantum efficiency is an important subject to realize those proposed applications. Recently we have developed the strain compensated superlattice (SL) photocathode. In the strain compensated SLs, the equivalent compressive and tensile strains introduced in the well and barrier SL layers so that strain relaxation is effectively suppressed with increasing the SL layer thickness and high crystal quality can be expected. In this study, we fabricated the GaAs/GaAsP strain compensated SLs with the thickness up to 90-pair SL layers. Up to now, the electron spin polarization of 92 % and the quantum efficiency of 1.6 % were simultaneously achieved from 24-pair sample. In the presentation, we show the effect of the superlattice thickness on the photocathode performances and discuss the photocathode physics.
	Slides WEAD3 [3.064 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEAD3
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Commissioning and Recent Experimental Results at the Argonne Wakefield Accelerator Facility (AWA)

2472

M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, J.H. Shao, D. Wang, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
J.H. Shao, D. Wang
TUB, Beijing, People's Republic of China

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
The commissioning of the upgraded AWA facility has been recently completed. The L-band electron gun has been fully commissioned and has been successfully operated with its Cesium Telluride photocathode at a gradient of 80 MV/m. Single bunches of up to 100 nC, and bunch trains of up to 32 bunches have been generated. The six new pi-mode accelerating cavities bring the beam energy to 75 MeV. Initial measurements of the beam parameters have been performed. This intense beam has been used to drive high gradient wakefields in several structures. A second beamline provides electron bunches to probe the wakefields generated by the intense drive beam. One of the main goals of the facility is to generate short RF pulses with GW power levels, corresponding to accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure.

Slides WEAD1 [2.091 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEAD1

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEAD2

Experimental Results of Carbon NanoTube Cathodes inside RF Environment

2475

L. Faillace, S. Boucher, J.J. Hartzell, A.Y. Murokh
RadiaBeam, Santa Monica, California, USA
D. Mihalcea, P. Piot, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA
H. Panuganti
Northern Illinois University, DeKalb, Illinois, USA

Funding: Work supported by US DOE SBIR grant # DE-SC0004459
Carbon Nano Tubes (CNT’s) as field-emitters have been investigated for more than two decades and can produce relatively low emittance electron beams for a given cathode size. Unlike thermionic cathodes, CNT cathodes are able to produce electrons at room temperature and relatively low electric field (a few MV/m). In collaboration with FermiLab, we have recently tested CNT cathodes both with DC and RF fields. We observed a beam current close to 1A with a ~1cm² CNT cathode inside an L-band RF gun. Steady operation was obtained up to 650 mA and the measured current vs. surface field plot showed perfect agreement with the Fowler-Nordheim distribution.

Slides WEAD2 [10.445 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEAD2

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEAD3

Quantum Efficiency Improvement of Polarized Electron Source using Strain Compensated Super Lattice Photocathode

2479

N. Yamamoto, M. Hosaka, A. Mano, T. Miyauchi, Y. Takashima, Y. Takeda
Nagoya University, Nagoya, Japan
X.J. Jin, M. Yamamoto
KEK, Ibaraki, Japan

Polarized electron beam is essential for future electron-positron colliders and electron-ion colliders. Improving the quantum efficiency is an important subject to realize those proposed applications. Recently we have developed the strain compensated superlattice (SL) photocathode. In the strain compensated SLs, the equivalent compressive and tensile strains introduced in the well and barrier SL layers so that strain relaxation is effectively suppressed with increasing the SL layer thickness and high crystal quality can be expected. In this study, we fabricated the GaAs/GaAsP strain compensated SLs with the thickness up to 90-pair SL layers. Up to now, the electron spin polarization of 92 % and the quantum efficiency of 1.6 % were simultaneously achieved from 24-pair sample. In the presentation, we show the effect of the superlattice thickness on the photocathode performances and discuss the photocathode physics.

Slides WEAD3 [3.064 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEAD3

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)