IPAC2011 - List of Authors (Calatroni, S.)

Paper	Title	Page
MOPC104	HIE-ISOLDE SRF Development Activities at CERN	316
	M. Therasse, O. Brunner, S. Calatroni, J.K. Chambrillon, B. Delaup, M. Pasini CERN, Geneva, Switzerland
	The HIE-ISOLDE project has initiated a new development phase on the SRF domain at CERN. In particular, the HIE-ISOLDE project aims at the construction of the 32 Quarter Wave Resonators (QWRs) using the Nb on Cu sputtering technology. The paper describes the refurbishment of the test infrastructure and the activities from the cavity production to the cold test, including quality assurance procedure for the correct handling of the resonators.

MOPS083	Update on Electron Cloud Mitigation Studies at Cesr-TA*	796
	J.R. Calvey, M.G. Billing, J.V. Conway, G. Dugan, S. Greenwald, Y. Li, X. Liu, J.A. Livezey, J. Makita, R.E. Meller, M.A. Palmer, S. Santos, R.M. Schwartz, J.P. Sikora, C.R. Strohman CLASSE, Ithaca, New York, USA S. Calatroni, G. Rumolo CERN, Geneva, Switzerland K. Kanazawa, Y. Suetsugu KEK, Ibaraki, Japan M.T.F. Pivi, L. Wang SLAC, Menlo Park, California, USA
	Funding: Work supported by the US National Science Foundation (PHY-0734867) and Department of Energy (DE-FC02-08ER41538) Over the course of the past three years, the Cornell Electron Storage Ring (CESR) has been reconfigured to serve as a test facility for next generation particle accelerators. A significant part of this program has been the installation of several diagnostic devices to measure and quantify the electron cloud effect, a potential limiting factor in these machines. In particular, more than 30 Retarding Field Analyzers (RFAs) have been installed in CESR. These devices measure the local electron cloud density and energy distribution, and can be used to evaluate the efficacy of different cloud mitigation techniques. This paper will provide an overview of RFA results obtained at CesrTA over the past year, including measurements taken as function of bunch spacing and wiggler magnetic field. Understanding these results provides a great deal of insight into the behavior of the electron cloud.

TUPS027	Characterization of Carbon Coatings with Low Secondary Electron Yield	1587
	C. Yin Vallgren, S. Calatroni, P. Costa Pinto, A. Kuzucan, H. Neupert, M. Taborelli CERN, Geneva, Switzerland
	Amorphous carbon (a-C) coatings can reliably be produced with a maximum secondary electron yield (SEY) close to 1 at room temperature. Measurements at low temperature (LHe) are in progress. Analysis by X-ray Photoemission Spectroscopy (XPS) shows a correlation between the lineshape of C1s spectrum in XPS and maximum SEY of the investigated samples. The initial level of oxygen on the surface of the various samples does not seem to be related to the initial maximum SEY value. However, the increase of the SEY with air exposure time on each individual sample is related to the amount of oxygen containing adsorbates. Storage in different environments has been investigated (static vacuum, aluminum foil, dry nitrogen and desiccators) and shows significant differences in the “aging” behavior. Aging is very moderate when storing samples wrapped in aluminum foil in air. Samples which have undergone aging due to inappropriate storage can be recovered nearly to the initial value of the SEY by typical surface treatments as ion bombardment, annealing under vacuum and conditioning by electron beam. However, an enhanced sensitivity to air exposures is observed for most of these curing methods.

TUPS099	A Study of the Surface Quality of High Purity Copper after Heat Treatment	1771
	M. Aicheler, G. Arnau-Izquierdo, S. Atieh, S. Calatroni, S. Lebet, G. Riddone, A. Samoshkin CERN, Geneva, Switzerland
	The manufacturing flow of accelerating structures for the compact linear collider, based on diamond-machined high purity copper components, include several thermal cycles (diffusion bonding, brazing of cooling circuits, baking in vacuum, etc.). The high temperature cycles may be carried out following different schedules and environments (vacuum, reducing hydrogen atmosphere, argon, etc.) and develop peculiar surface topographies which have been the object of extended observations. This study presents and discusses the results of scanning electron microscopy (SEM) and optical microscopy investigations.

WEPC135	Recent Developments in Modeling Time-resolved Shielded-pickup Measurements of Electron Cloud Buildup at CESRTA	2313
	J.A. Crittenden, Y. Li, X. Liu, M.A. Palmer, J.P. Sikora CLASSE, Ithaca, New York, USA R.P. Badman Syracuse University, Syracuse, USA S. Calatroni, G. Rumolo CERN, Geneva, Switzerland S. Kato KEK, Ibaraki, Japan
	Funding: Work supported by the U.S. National Science Foundation PHY-0734867, PHY-1002467 and the U.S. Department of Energy DE-FC02-08ER41538 The Cornell Electron Storage Ring Test Accelerator program includes investigations into the mitigation of electron cloud buildup using a variety of techniques in custom vacuum chambers. The CESR ring accommodates two such chambers equipped with BPM-style pickup detectors shielded against the direct beam-induced signal. The signals provide time-resolved information on cloud development. Results for diamond-like carbon, amorphous carbon, and TiN coatings have been compared to those for an uncoated aluminum chamber. Here we report on extensions to the ECLOUD modeling code which refine its description of a variety of new types of in situ vacuum chamber comparisons. Our results highlight the sensitivity afforded by these measurements to the modeled photoelectron production and secondary yield parameters. We draw conclusions comparing the photoelectron and secondary yield properties of the various vacuum chamber coatings, including conditioning effects as a function of synchrotron radiation dose. We find substantial conditioning effects in both the quantum efficiency for producing photoelectrons and in the secondary yield.

Paper

Title

Page

HIE-ISOLDE SRF Development Activities at CERN

316

M. Therasse, O. Brunner, S. Calatroni, J.K. Chambrillon, B. Delaup, M. Pasini
CERN, Geneva, Switzerland

The HIE-ISOLDE project has initiated a new development phase on the SRF domain at CERN. In particular, the HIE-ISOLDE project aims at the construction of the 32 Quarter Wave Resonators (QWRs) using the Nb on Cu sputtering technology. The paper describes the refurbishment of the test infrastructure and the activities from the cavity production to the cold test, including quality assurance procedure for the correct handling of the resonators.

MOPS083

Update on Electron Cloud Mitigation Studies at Cesr-TA*

796

J.R. Calvey, M.G. Billing, J.V. Conway, G. Dugan, S. Greenwald, Y. Li, X. Liu, J.A. Livezey, J. Makita, R.E. Meller, M.A. Palmer, S. Santos, R.M. Schwartz, J.P. Sikora, C.R. Strohman
CLASSE, Ithaca, New York, USA
S. Calatroni, G. Rumolo
CERN, Geneva, Switzerland
K. Kanazawa, Y. Suetsugu
KEK, Ibaraki, Japan
M.T.F. Pivi, L. Wang
SLAC, Menlo Park, California, USA

Funding: Work supported by the US National Science Foundation (PHY-0734867) and Department of Energy (DE-FC02-08ER41538)
Over the course of the past three years, the Cornell Electron Storage Ring (CESR) has been reconfigured to serve as a test facility for next generation particle accelerators. A significant part of this program has been the installation of several diagnostic devices to measure and quantify the electron cloud effect, a potential limiting factor in these machines. In particular, more than 30 Retarding Field Analyzers (RFAs) have been installed in CESR. These devices measure the local electron cloud density and energy distribution, and can be used to evaluate the efficacy of different cloud mitigation techniques. This paper will provide an overview of RFA results obtained at CesrTA over the past year, including measurements taken as function of bunch spacing and wiggler magnetic field. Understanding these results provides a great deal of insight into the behavior of the electron cloud.

TUPS027

Characterization of Carbon Coatings with Low Secondary Electron Yield

1587

C. Yin Vallgren, S. Calatroni, P. Costa Pinto, A. Kuzucan, H. Neupert, M. Taborelli
CERN, Geneva, Switzerland

Amorphous carbon (a-C) coatings can reliably be produced with a maximum secondary electron yield (SEY) close to 1 at room temperature. Measurements at low temperature (LHe) are in progress. Analysis by X-ray Photoemission Spectroscopy (XPS) shows a correlation between the lineshape of C1s spectrum in XPS and maximum SEY of the investigated samples. The initial level of oxygen on the surface of the various samples does not seem to be related to the initial maximum SEY value. However, the increase of the SEY with air exposure time on each individual sample is related to the amount of oxygen containing adsorbates. Storage in different environments has been investigated (static vacuum, aluminum foil, dry nitrogen and desiccators) and shows significant differences in the “aging” behavior. Aging is very moderate when storing samples wrapped in aluminum foil in air. Samples which have undergone aging due to inappropriate storage can be recovered nearly to the initial value of the SEY by typical surface treatments as ion bombardment, annealing under vacuum and conditioning by electron beam. However, an enhanced sensitivity to air exposures is observed for most of these curing methods.

TUPS099

A Study of the Surface Quality of High Purity Copper after Heat Treatment

1771

M. Aicheler, G. Arnau-Izquierdo, S. Atieh, S. Calatroni, S. Lebet, G. Riddone, A. Samoshkin
CERN, Geneva, Switzerland

The manufacturing flow of accelerating structures for the compact linear collider, based on diamond-machined high purity copper components, include several thermal cycles (diffusion bonding, brazing of cooling circuits, baking in vacuum, etc.). The high temperature cycles may be carried out following different schedules and environments (vacuum, reducing hydrogen atmosphere, argon, etc.) and develop peculiar surface topographies which have been the object of extended observations. This study presents and discusses the results of scanning electron microscopy (SEM) and optical microscopy investigations.

WEPC135

Recent Developments in Modeling Time-resolved Shielded-pickup Measurements of Electron Cloud Buildup at CESRTA

2313

J.A. Crittenden, Y. Li, X. Liu, M.A. Palmer, J.P. Sikora
CLASSE, Ithaca, New York, USA
R.P. Badman
Syracuse University, Syracuse, USA
S. Calatroni, G. Rumolo
CERN, Geneva, Switzerland
S. Kato
KEK, Ibaraki, Japan

Funding: Work supported by the U.S. National Science Foundation PHY-0734867, PHY-1002467 and the U.S. Department of Energy DE-FC02-08ER41538
The Cornell Electron Storage Ring Test Accelerator program includes investigations into the mitigation of electron cloud buildup using a variety of techniques in custom vacuum chambers. The CESR ring accommodates two such chambers equipped with BPM-style pickup detectors shielded against the direct beam-induced signal. The signals provide time-resolved information on cloud development. Results for diamond-like carbon, amorphous carbon, and TiN coatings have been compared to those for an uncoated aluminum chamber. Here we report on extensions to the ECLOUD modeling code which refine its description of a variety of new types of in situ vacuum chamber comparisons. Our results highlight the sensitivity afforded by these measurements to the modeled photoelectron production and secondary yield parameters. We draw conclusions comparing the photoelectron and secondary yield properties of the various vacuum chamber coatings, including conditioning effects as a function of synchrotron radiation dose. We find substantial conditioning effects in both the quantum efficiency for producing photoelectrons and in the secondary yield.