2011 Particle Accelerator Conference - Classification: Accelerator Technology / Tech 14: Vacuum Technology

Paper

Title

Page

Status of NSLS-II Storage Ring Vacuum Systems

1244

H.-C. Hseuh, A. Blednykh, L. Doom, M.J. Ferreira, C. Hetzel, J. Hu, S. Leng, C. Longo, V. Ravindranath, K. Roy, S.K. Sharma, F.J. Willeke, K. Wilson, D. Zigrosser
BNL, Upton, Long Island, New York, USA

Funding: Work performed under the auspices of U.S. Department of Energy, under contract DE-AC02-98CH10886
National Synchrotron Light Source II (NSLS-II), being constructed at Brookhaven National Laboratory, is a 3- GeV, high-flux and high-brightness synchrotron radiation facility with a nominal current of 500 mA. The storage ring vacuum system has extruded aluminium chambers, with ante-chamber for photon fans and distributed NEG strip pumping. Discrete photon absorbers are used to intercept the un-used bending magnet radiation. In-situ bakeout is implemented to achieve fast conditioning during initial commissioning and after interventions.

TUP228

Design of the EBIS Vacuum System

1247

M. Mapes, L. Smart, D. Weiss
BNL, Upton, Long Island, New York, USA

At Brookhaven National Labratory the Electron Beam Ion Source (EBIS) is presently being commisioned. The EBIS will be a new heavy ion pre-injector for the Realativistic Heavy Ion Collider (RHIC). The new pre-injector has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium. The background pressure in the ionization region of the EBIS should be low enough that it does not produce a significant number of ions from background gas. The pressure in the regions of the electron gun and electron collector can be higher than in the ionization region provided there is efficient vacuum separation between the sections. For injection the ions must be accelerated to 100KV by pulsing the EBIS platform. All associated equipment including the vacuum equipment on the platform will be at a 100KV potential. The vacuum system design and the vacuum controls for the EBIS platform and transport system will be presented as well as the interface with the Booster Ring which has a pressure 10^-11 Torr.

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.

TUP231

Applications of Textured Dysprosium Concentrators in Ultra-Short Period Insertion Devices

1256

A.Y. Murokh, R.B. Agustsson, P. Frigola
RadiaBeam, Santa Monica, USA
O.V. Chubar, V. Solovyov
BNL, Upton, Long Island, New York, USA

The next generation light sources require development of the insertion devices with shorter periods and higher peak field values, well beyond the presently available designs limited by magnetic properties of conventional materials. Dysprosium (Dy) is a rare earth metal with unique ferromagnetic properties below 90 K, including saturation inductance above 3.4 Tesla. However, due to the high magnetic anisotropy of Dy, such a high level of magnetization can only be realized when the external field lies in the basal plane. This requirement is partially satisfied in the textured dysprosium presently under development at RadiaBeam and BNL. Textured Dy development status is discussed, as well as potential applications as field concentrators in the insertion devices, with particular emphasis on the next generation of cryogenically cooled short period hybrid undulators.

THOBS5

Extruded Aluminum Vacuum Chambers for Insertion Devices

2093

E. Trakhtenberg, P.K. Den Hartog, G.E. Wiemerslage
ANL, Argonne, USA

Funding: Work is supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Science under Contract No. DE-AC02-06CH 11357.
Extruded aluminum vacuum chambers are commonly used in the storage rings of synchrotron facilities. For 18 years the APS has designed and fabricated vacuum chambers made from extruded aluminum for use with insertion devices at the APS and for use at other facilities including BESSY II, the Swiss Light Source (SLS), the Canadian Light Source (CLS), the TESLA Test Facility (TTF), and the European Synchrotron Radiation Facility (ESRF). Most recently extruded aluminum chambers were developed for LCLS with a 0.5-mm wall thickness along the entire 3.8-meter length. Surface roughness for the LCLS vacuum chamber interior was reduced, on average, to less than 300 nm through an abrasive flow polishing technique. Currently under development is an extruded aluminum chamber for the superconducting undulator at the APS. So far, 120 vacuum chambers have been produced with these methods. Results of the development, construction, and manufacturing of extruded aluminum vacuum chambers with small vertical apertures and thin walls are presented. The design, technological challenges, and positive and negative experiences are discussed.

Slides THOBS5 [7.855 MB]

THOBS6

Thin Film Coatings for Suppressing Electron Multipacting in Particle Accelerators

2096

P. Costa Pinto, S. Calatroni, P. Chiggiato, H. Neupert, E.N. Shaposhnikova, M. Taborelli, W. Vollenberg, C. Yin Vallgren
CERN, Geneva, Switzerland

Thin film coatings are an effective way for suppressing electron multipacting in particle accelerators. For bakeable beam pipes, the TiZrV Non Evaporable Getter (NEG) developed at CERN can provide a Secondary Electron Yield (SEY) of 1.1 after activation at 180oC (24h). The coating process was implemented in large scale to coat the long straight sections and the experimental beam pipes for the Large Hadron Collider (LHC). For non bakeable beam pipes, as those of the Super Proton Synchrotron (SPS), CERN started a campaign to develop a coating having a low SEY without need of in situ heating. Magnetron sputtered carbon thin films have shown SEY of 1 with marginal deterioration when exposed in air for months. This material is now being tested in both laboratory and accelerator environment. At CERN’s SPS, tests with electron cloud monitors attached to carbon coated chambers show no degradation of the coating after two years of operation interleaved with a total of 3 months of air exposure during shutdown periods. This paper presents the SEY characteristics of both TiZrV and carbon films, the coating processes and the proposed route towards large scale production for the carbon coatings.

Slides THOBS6 [4.620 MB]

Paper	Title	Page
TUP227	Status of NSLS-II Storage Ring Vacuum Systems	1244
	H.-C. Hseuh, A. Blednykh, L. Doom, M.J. Ferreira, C. Hetzel, J. Hu, S. Leng, C. Longo, V. Ravindranath, K. Roy, S.K. Sharma, F.J. Willeke, K. Wilson, D. Zigrosser BNL, Upton, Long Island, New York, USA
	Funding: Work performed under the auspices of U.S. Department of Energy, under contract DE-AC02-98CH10886 National Synchrotron Light Source II (NSLS-II), being constructed at Brookhaven National Laboratory, is a 3- GeV, high-flux and high-brightness synchrotron radiation facility with a nominal current of 500 mA. The storage ring vacuum system has extruded aluminium chambers, with ante-chamber for photon fans and distributed NEG strip pumping. Discrete photon absorbers are used to intercept the un-used bending magnet radiation. In-situ bakeout is implemented to achieve fast conditioning during initial commissioning and after interventions.

TUP228	Design of the EBIS Vacuum System	1247
	M. Mapes, L. Smart, D. Weiss BNL, Upton, Long Island, New York, USA
	At Brookhaven National Labratory the Electron Beam Ion Source (EBIS) is presently being commisioned. The EBIS will be a new heavy ion pre-injector for the Realativistic Heavy Ion Collider (RHIC). The new pre-injector has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium. The background pressure in the ionization region of the EBIS should be low enough that it does not produce a significant number of ions from background gas. The pressure in the regions of the electron gun and electron collector can be higher than in the ionization region provided there is efficient vacuum separation between the sections. For injection the ions must be accelerated to 100KV by pulsing the EBIS platform. All associated equipment including the vacuum equipment on the platform will be at a 100KV potential. The vacuum system design and the vacuum controls for the EBIS platform and transport system will be presented as well as the interface with the Booster Ring which has a pressure 10^-11 Torr.

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.

TUP231	Applications of Textured Dysprosium Concentrators in Ultra-Short Period Insertion Devices	1256
	A.Y. Murokh, R.B. Agustsson, P. Frigola RadiaBeam, Santa Monica, USA O.V. Chubar, V. Solovyov BNL, Upton, Long Island, New York, USA
	The next generation light sources require development of the insertion devices with shorter periods and higher peak field values, well beyond the presently available designs limited by magnetic properties of conventional materials. Dysprosium (Dy) is a rare earth metal with unique ferromagnetic properties below 90 K, including saturation inductance above 3.4 Tesla. However, due to the high magnetic anisotropy of Dy, such a high level of magnetization can only be realized when the external field lies in the basal plane. This requirement is partially satisfied in the textured dysprosium presently under development at RadiaBeam and BNL. Textured Dy development status is discussed, as well as potential applications as field concentrators in the insertion devices, with particular emphasis on the next generation of cryogenically cooled short period hybrid undulators.

THOBS5	Extruded Aluminum Vacuum Chambers for Insertion Devices	2093
	E. Trakhtenberg, P.K. Den Hartog, G.E. Wiemerslage ANL, Argonne, USA
	Funding: Work is supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Science under Contract No. DE-AC02-06CH 11357. Extruded aluminum vacuum chambers are commonly used in the storage rings of synchrotron facilities. For 18 years the APS has designed and fabricated vacuum chambers made from extruded aluminum for use with insertion devices at the APS and for use at other facilities including BESSY II, the Swiss Light Source (SLS), the Canadian Light Source (CLS), the TESLA Test Facility (TTF), and the European Synchrotron Radiation Facility (ESRF). Most recently extruded aluminum chambers were developed for LCLS with a 0.5-mm wall thickness along the entire 3.8-meter length. Surface roughness for the LCLS vacuum chamber interior was reduced, on average, to less than 300 nm through an abrasive flow polishing technique. Currently under development is an extruded aluminum chamber for the superconducting undulator at the APS. So far, 120 vacuum chambers have been produced with these methods. Results of the development, construction, and manufacturing of extruded aluminum vacuum chambers with small vertical apertures and thin walls are presented. The design, technological challenges, and positive and negative experiences are discussed.
	Slides THOBS5 [7.855 MB]

THOBS6	Thin Film Coatings for Suppressing Electron Multipacting in Particle Accelerators	2096
	P. Costa Pinto, S. Calatroni, P. Chiggiato, H. Neupert, E.N. Shaposhnikova, M. Taborelli, W. Vollenberg, C. Yin Vallgren CERN, Geneva, Switzerland
	Thin film coatings are an effective way for suppressing electron multipacting in particle accelerators. For bakeable beam pipes, the TiZrV Non Evaporable Getter (NEG) developed at CERN can provide a Secondary Electron Yield (SEY) of 1.1 after activation at 180oC (24h). The coating process was implemented in large scale to coat the long straight sections and the experimental beam pipes for the Large Hadron Collider (LHC). For non bakeable beam pipes, as those of the Super Proton Synchrotron (SPS), CERN started a campaign to develop a coating having a low SEY without need of in situ heating. Magnetron sputtered carbon thin films have shown SEY of 1 with marginal deterioration when exposed in air for months. This material is now being tested in both laboratory and accelerator environment. At CERN’s SPS, tests with electron cloud monitors attached to carbon coated chambers show no degradation of the coating after two years of operation interleaved with a total of 3 months of air exposure during shutdown periods. This paper presents the SEY characteristics of both TiZrV and carbon films, the coating processes and the proposed route towards large scale production for the carbon coatings.
	Slides THOBS6 [4.620 MB]