2011 Particle Accelerator Conference - Classification: Sources and Medium Energy Accelerators / Accel/Storage Rings 16: Energy Recovery Linacs

Paper	Title	Page
WEP244	Growth and Characterization of Bialkali Photocathodes for Cornell ERL Injector	1942
	L. Cultrera, I.V. Bazarov, J.V. Conway, B.M. Dunham, Y. Li, X. Liu, K.W. Smolenski CLASSE, Ithaca, New York, USA S.S. Karkare, J.M. Maxson Cornell University, Ithaca, New York, USA
	The requirements of high quantum efficiency in the visible spectral range and that of an increased lifetime as compared to cesiated GaAs can be met by multi-alkali photocathodes, either CsKSb or NaKSb. In this paper we detail the procedures that allow the growth of thin films suitable for the ERL photoinjector operating at Cornell University. Quantum efficiency, spectral response, and surface characterization of deposited samples is presented. A load-locked multi-alkali cathode growth system is also described.

WEP245	Optimization of DC Photogun Electrode Geometry	1945
	J.M. Maxson Cornell University, Ithaca, New York, USA I.V. Bazarov, B.M. Dunham, K.W. Smolenski CLASSE, Ithaca, New York, USA
	DC photoguns that employ electrostatic focusing to obtain lower beam emittance must inherently trade off between focusing strength and the field at the photocathode, and are traditionally pushed to the limits of breakdown voltage. In this paper, we numerically investigate a highly parametrized electrostatic geometry exploring the trade-off between the voltage breakdown condition and electrostatic focusing. We then compare the results to DC gun designs where the focusing is introduced via embedded solenoidal fields. Finally, we present investigations for a multi-anode gun design that seeks to simultaneously achieve both high electric field at the photocathode and high gun voltage without violating the empirical voltage breakdown condition. In the most feasible cases, the electrode geometry is optimized via genetic algorithms. Designs on the optimal front are compared with the current performance of the Cornell ERL prototype DC photogun.

Paper

Title

Page

Growth and Characterization of Bialkali Photocathodes for Cornell ERL Injector

1942

L. Cultrera, I.V. Bazarov, J.V. Conway, B.M. Dunham, Y. Li, X. Liu, K.W. Smolenski
CLASSE, Ithaca, New York, USA
S.S. Karkare, J.M. Maxson
Cornell University, Ithaca, New York, USA

The requirements of high quantum efficiency in the visible spectral range and that of an increased lifetime as compared to cesiated GaAs can be met by multi-alkali photocathodes, either CsKSb or NaKSb. In this paper we detail the procedures that allow the growth of thin films suitable for the ERL photoinjector operating at Cornell University. Quantum efficiency, spectral response, and surface characterization of deposited samples is presented. A load-locked multi-alkali cathode growth system is also described.

WEP245

Optimization of DC Photogun Electrode Geometry

1945

J.M. Maxson
Cornell University, Ithaca, New York, USA
I.V. Bazarov, B.M. Dunham, K.W. Smolenski
CLASSE, Ithaca, New York, USA

DC photoguns that employ electrostatic focusing to obtain lower beam emittance must inherently trade off between focusing strength and the field at the photocathode, and are traditionally pushed to the limits of breakdown voltage. In this paper, we numerically investigate a highly parametrized electrostatic geometry exploring the trade-off between the voltage breakdown condition and electrostatic focusing. We then compare the results to DC gun designs where the focusing is introduced via embedded solenoidal fields. Finally, we present investigations for a multi-anode gun design that seeks to simultaneously achieve both high electric field at the photocathode and high gun voltage without violating the empirical voltage breakdown condition. In the most feasible cases, the electrode geometry is optimized via genetic algorithms. Designs on the optimal front are compared with the current performance of the Cornell ERL prototype DC photogun.