2011 Particle Accelerator Conference - List of Authors (Conway, J.V.)

Paper	Title	Page
TUP229	Implementation and Operation of Electron Cloud Diagnostics for CesrTA	1250
	Y. Li, J.V. Conway, X. Liu, V. Medjidzade, M.A. Palmer CLASSE, Ithaca, New York, USA
	Funding: Work Supported by NSF Grant #PHY-0734867 & DOE Grant #DE-FC02-08ER41538 The vacuum system of Cornell Electron Storage Ring (CESR) was successfully reconfigured to support CesrTA physics programs, including electron cloud (EC) build-up and suppression studies. One of key features of the reconfigured CESR vacuum system is the flexibility for exchange of various vacuum chambers with minimized impact to the accelerator operations. This is achieved by creation of three short gate-valve isolated vacuum sections. Over the last three years, many vacuum chambers with various EC diagnostics (such as RFAs, shielded pickups, etc) were rotated through these short experimental sections. With these instrumented test chambers, EC build-up was studied in many magnetic field types, including dipoles, quadrupoles, wigglers and field-free drifts. EC suppression techniques by coating (TiN, NEG and amorphous-C), surface textures (grooves) and clearing electrode are incorporated in these test chambers to evaluate their vacuum performance and EC suppression effectiveness. We present the implementation and operations of EC diagnostics.

TUP230	In-situ Secondary Electron Yield Measurement System at CesrTA	1253
	Y. Li, J.V. Conway, S. Greenwald, J.-S. Kim, V. Medjidzade, T.P. Moore, M.A. Palmer, C.R. Strohman CLASSE, Ithaca, New York, USA D. Asner Carleton University, College of Natural Sciences, Ottawa, Ontario, Canada
	Funding: Work Supported by NSF Grant #PHY-0734867 & DOE Grant #DE-FC02-08ER41538 Measuring the secondary electron yield (SEY) on technical surfaces in accelerator vacuum systems provides essential information for the study of electron cloud growth and suppression, with application to many accelerator R&D projects. As a part of the CesrTA research program, we developed and deployed an in-situ SEY measurement system. A two-sample SEY system was installed in the CesrTA vacuum system with one sample exposed to direct synchrotron radiation (SR) and the other sample exposed to scattered SR. The SEYs of both samples were measured as a function of the SR dosages. In this paper, we describe the in-situ SEY measurement systems and the initial results on bare aluminum (6061-T6), TiN-coated aluminum, amorphous carbon-coated aluminum, and amorphous carbon-coated copper samples.

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.

Paper

Title

Page

Implementation and Operation of Electron Cloud Diagnostics for CesrTA

1250

Y. Li, J.V. Conway, X. Liu, V. Medjidzade, M.A. Palmer
CLASSE, Ithaca, New York, USA

Funding: Work Supported by NSF Grant #PHY-0734867 & DOE Grant #DE-FC02-08ER41538
The vacuum system of Cornell Electron Storage Ring (CESR) was successfully reconfigured to support CesrTA physics programs, including electron cloud (EC) build-up and suppression studies. One of key features of the reconfigured CESR vacuum system is the flexibility for exchange of various vacuum chambers with minimized impact to the accelerator operations. This is achieved by creation of three short gate-valve isolated vacuum sections. Over the last three years, many vacuum chambers with various EC diagnostics (such as RFAs, shielded pickups, etc) were rotated through these short experimental sections. With these instrumented test chambers, EC build-up was studied in many magnetic field types, including dipoles, quadrupoles, wigglers and field-free drifts. EC suppression techniques by coating (TiN, NEG and amorphous-C), surface textures (grooves) and clearing electrode are incorporated in these test chambers to evaluate their vacuum performance and EC suppression effectiveness. We present the implementation and operations of EC diagnostics.

TUP230

In-situ Secondary Electron Yield Measurement System at CesrTA

1253

Y. Li, J.V. Conway, S. Greenwald, J.-S. Kim, V. Medjidzade, T.P. Moore, M.A. Palmer, C.R. Strohman
CLASSE, Ithaca, New York, USA
D. Asner
Carleton University, College of Natural Sciences, Ottawa, Ontario, Canada

Funding: Work Supported by NSF Grant #PHY-0734867 & DOE Grant #DE-FC02-08ER41538
Measuring the secondary electron yield (SEY) on technical surfaces in accelerator vacuum systems provides essential information for the study of electron cloud growth and suppression, with application to many accelerator R&D projects. As a part of the CesrTA research program, we developed and deployed an in-situ SEY measurement system. A two-sample SEY system was installed in the CesrTA vacuum system with one sample exposed to direct synchrotron radiation (SR) and the other sample exposed to scattered SR. The SEYs of both samples were measured as a function of the SR dosages. In this paper, we describe the in-situ SEY measurement systems and the initial results on bare aluminum (6061-T6), TiN-coated aluminum, amorphous carbon-coated aluminum, and amorphous carbon-coated copper samples.

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.