FEL2013 - List of Authors (Ben-Zvi, I.)

Paper	Title	Page
TUPSO63	High Average Brightness Photocathode Development for FEL Applications	376
	T. Rao, I. Ben-Zvi, J. Skaritka, E. Wang BNL, Upton, Long Island, New York, USA
	Next generation, high average flux, light sources call for electron beams with high average current as well as high peak brightness. Alkali antimonide cathodes, especially K2CsSb show great promise in delivering electron beams to meet these requirements. In the past few years, there have been a number of experiments geared towards understanding the stoichiometry, crystalline structure, surface properties and sensitivity of these cathodes. At BNL, we have used the x-ray beams from NSLS, CFN and CHESS for in-situ characterization of K-Cs-Sb cathode growth. We have also designed and built several load-lock systems for ex-situ cathode fabrication and quick cathode exchange, to be used with a number of guns. One load-lock system/cathode combination has been tested with a DC gun and the others will be tested with SRF guns operating at 112 and 704 MHz. In this paper we will present the results on improving the QE with excimer laser and the performance of the load-lock/cathode combination in the guns.

WEPSO31	THz Radiation Source Potential of the R&D ERL at BNL	566
	D. Kayran, I. Ben-Zvi, Y.C. Jing, B. Sheehy BNL, Upton, Long Island, New York, USA
	Funding: Work supported by BSA DOE, Contract No. DE-AC02-98CH10886 An ampere class 20 MeV superconducting Energy Recovery Linac (ERL) is under commissioning at Brookhaven National Laboratory (BNL) for testing concepts for high-energy electron cooling and electron-ion colliders. This ERL will be used as a test bed to study issues relevant for very high current ERLs. High repetition rate (9.5 MHz), CW operation and high performance of electron beam with some additional components make this ERL an excellent driver for high power coherent THz radiation source. We discuss potential use of BNL ERL as a source of THz radiation and results of the beam dynamics simulation. We present the status and commissioning progress of the ERL. Ilan Ben-Zvi. et al. Coherent harmonic generation of THz radiation using wakefield bunching (presented at this conference)

TUPSO76	In Situ Characterization of ALKALI Antimonide Photocathodes	403
	J. Smedley, K. Attenkofer, S.G. Schubert BNL, Upton, Long Island, New York, USA I. Ben-Zvi, X. Liang, E.M. Muller, M. Ruiz-Osés Stony Brook University, Stony Brook, USA M. DeMarteau Fermilab, Batavia, USA H.A. Padmore, J.J. Wong LBNL, Berkeley, California, USA A.R. Woll Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J. Xie ANL, Argonne, USA
	Funding: The authors wish to acknowledge the support of the US DOE, under Contract No. KC0407-ALSJNT-I0013, DE-AC02-98CH10886 and DE-SC0005713. Use of CHESS is supported by NSF award DMR-0936384. Alkali antimonide photocathodes are a prime candidate for use in high-brightness photoinjectors of free electron lasers and 4th generation light sources. These materials have complex growth kinetics - many methods exist for forming the compounds, each with different grain size, roughness, and crystalline texture. These parameters impact the performance of the cathodes, including efficiency, intrinsic emittance and lifetime. In situ analysis of the growth of these materials has allowed investigation of correlations between cathode structure and growth parameters and the resulting quantum efficiency (QE). The best cathodes have a QE at 532 nm in excess of 6% and are structurally textured K2CsSb with grain sizes in excess of 20 nm. X-ray reflection (XRR) has been used to characterize the roughness evolution of the cathode, while X-ray Diffraction (XRD) has been used to characterize the texture, grain size and stoichometry.

Paper

Title

Page

High Average Brightness Photocathode Development for FEL Applications

376

T. Rao, I. Ben-Zvi, J. Skaritka, E. Wang
BNL, Upton, Long Island, New York, USA

Next generation, high average flux, light sources call for electron beams with high average current as well as high peak brightness. Alkali antimonide cathodes, especially K2CsSb show great promise in delivering electron beams to meet these requirements. In the past few years, there have been a number of experiments geared towards understanding the stoichiometry, crystalline structure, surface properties and sensitivity of these cathodes. At BNL, we have used the x-ray beams from NSLS, CFN and CHESS for in-situ characterization of K-Cs-Sb cathode growth. We have also designed and built several load-lock systems for ex-situ cathode fabrication and quick cathode exchange, to be used with a number of guns. One load-lock system/cathode combination has been tested with a DC gun and the others will be tested with SRF guns operating at 112 and 704 MHz. In this paper we will present the results on improving the QE with excimer laser and the performance of the load-lock/cathode combination in the guns.

WEPSO31

THz Radiation Source Potential of the R&D ERL at BNL

566

D. Kayran, I. Ben-Zvi, Y.C. Jing, B. Sheehy
BNL, Upton, Long Island, New York, USA

Funding: Work supported by BSA DOE, Contract No. DE-AC02-98CH10886
An ampere class 20 MeV superconducting Energy Recovery Linac (ERL) is under commissioning at Brookhaven National Laboratory (BNL) for testing concepts for high-energy electron cooling and electron-ion colliders. This ERL will be used as a test bed to study issues relevant for very high current ERLs. High repetition rate (9.5 MHz), CW operation and high performance of electron beam with some additional components make this ERL an excellent driver for high power coherent THz radiation source*. We discuss potential use of BNL ERL as a source of THz radiation and results of the beam dynamics simulation. We present the status and commissioning progress of the ERL.
*Ilan Ben-Zvi. et al. Coherent harmonic generation of THz radiation using wakefield bunching (presented at this conference)

TUPSO76

In Situ Characterization of ALKALI Antimonide Photocathodes

403

J. Smedley, K. Attenkofer, S.G. Schubert
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi, X. Liang, E.M. Muller, M. Ruiz-Osés
Stony Brook University, Stony Brook, USA
M. DeMarteau
Fermilab, Batavia, USA
H.A. Padmore, J.J. Wong
LBNL, Berkeley, California, USA
A.R. Woll
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J. Xie
ANL, Argonne, USA

Funding: The authors wish to acknowledge the support of the US DOE, under Contract No. KC0407-ALSJNT-I0013, DE-AC02-98CH10886 and DE-SC0005713. Use of CHESS is supported by NSF award DMR-0936384.
Alkali antimonide photocathodes are a prime candidate for use in high-brightness photoinjectors of free electron lasers and 4th generation light sources. These materials have complex growth kinetics - many methods exist for forming the compounds, each with different grain size, roughness, and crystalline texture. These parameters impact the performance of the cathodes, including efficiency, intrinsic emittance and lifetime. In situ analysis of the growth of these materials has allowed investigation of correlations between cathode structure and growth parameters and the resulting quantum efficiency (QE). The best cathodes have a QE at 532 nm in excess of 6% and are structurally textured K2CsSb with grain sizes in excess of 20 nm. X-ray reflection (XRR) has been used to characterize the roughness evolution of the cathode, while X-ray Diffraction (XRD) has been used to characterize the texture, grain size and stoichometry.