IPAC2017 - Classification: 07 Accelerator Technology / T14 Vacuum Technology

Paper	Title	Page
MOOCA3	Amorphous Carbon Thin Film Coating of the SPS Beamline: Evaluation of the First Coating Implementation	44
	M. Van Gompel, P. Chiggiato, P. Costa Pinto, P. Cruikshank, C. Pasquino, J. Perez Espinos, A. Sapountzis, M. Taborelli, W. Vollenberg CERN, Geneva, Switzerland
	As part of the LHC Injector Upgrade (LIU) project, the Super Proton Synchrotron (SPS) must be upgraded in order to inject in the LHC 25 ns bunch spaced beams of higher intensity. To mitigate the Electron Multipacting (EM) phenomenon in the SPS, CERN developed thin film carbon coatings with a low Secondary Electron Yield (SEY). The development went from coating small samples, up to coating of 6 m long vacuum chambers directly installed in the magnets. To deposit the low SEY amorphous carbon (aC) film on the vacuum chamber inner wall of SPS ring components, a modular hollow cathode train was designed. The minimization of the logistical impact requires a strategy combining in-situ and ex-situ coating, depending on the type of components. To validate the implementation strategy of the aC thin films and the in-situ coating process along the 7 km long SPS beamline, approximately 2 cells of B-type bending dipoles and 9 focussing quadrupoles are foreseen to be treated with the aC coating during the Extended Year End Technical Stop (EYETS) 2016-2017. We will discuss the coating technique and evaluate both the implementation process and the resulting coating performance.
	Slides MOOCA3 [71.421 MB]
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WEPIK025	Spectral Diagnostics of Argon Plasma in a 10mm Aperture Plasma Window	2978
	P.P. Gan, S. Huang, Y.R. Lu, S.Z. Wang, Z.X. Yuan, K. Zhu PKU, Beijing, People's Republic of China
	A 10 mm diameter 60 mm long plasma window has been designed and managed to generate arc discharge with argon gas experimentally in Peking University. Based on the previous experiments and simulations, we have measured the electron temperature and density of the plasma via argon spectral diagnostics, and analyzed the conditions to satisfy the criterion of local thermal equilibrium (L.T.E). The electron temperature is in the range of 12000 K to 16000 K. The electron density is in the range of 2.2×10¹⁶ cm^-3 to 3.2×10¹⁶ cm^-3, increasing with discharge current and gas flow rate. The results indicate that our argon plasma is in the L.T.E status. The sealing pressure characteristics of the plasma window is mentioned as well.
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WEPIK107	Comparison Studies of Graphene Sey Results in NSRL and DL	3196
	J. Wang, Y. Wang, B. Zhang, Y.X. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China B.S. Sian, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom P.V. Tyagi STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom R. Valizadeh, G.X. Xia Cockcroft Institute, Warrington, Cheshire, United Kingdom G.X. Xia UMAN, Manchester, United Kingdom G.L. Yu University of Manchester, Manchester, United Kingdom
	Graphene has many excellent properties, such as high electron carrier mobility, good thermal conductivity and transparency etc. The secondary electron yield (SEY) of graphene with copper substrate had been studied in National Synchrotron Radiation Laboratory (NSRL) of China. The results show that the maximum SEY ('max) of 6~8 layers graphene film with copper substrates is about 1.25. Further studies indicate that many factors can affect the SEY test results. The recent SEY tests of graphene films with copper substrates in Daresbury Laboratory (DL) of UK gave the maximum SEY of as-received copper, graphene samples with copper substrates are 1.89, 1.83, and 1.68, respectively, under the incident charge per unit surface (Q) of 7.6×10^-8 C 'mm-2. Meanwhile, the SEY test parameters and measurement results of graphene in both laboratories are compared and analysed. The effect of defects on the SEY results of graphene films with copper substrate is also discussed.
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WEPVA043	Study of the Suitability of 3D Printing for Ultra-High Vacuum Applications	3356
	S. Jenzer, M. Alves, N. Delerue, A. Gonnin, D. Grasset, F. Letellier-Cohen, B. Mercier, E. Mistretta, C. Prevost LAL, Orsay, France A. Vion BV Proto, Sévenans, France J-P. Wilmes AGS Fusion, Izernore, France
	Funding: IN2P3/CNRS In the recent year additive fabrication (3D printing) has revolutionized mechanical engineering by allowing the quick production of mechanical components with complex shapes. So far most of these components are made in plastic and therefore can not be used in accelerator beam pipes. We have investigated samples printed using a metal 3D printer to study their behavior under vacuum. We report on our first tests showing that such samples are vacuum compatible and comparing pumping time.
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WEPVA048	Particle Generation of CapaciTorr Pumps	3363
	S. Lederer, L. Lilje DESY, Hamburg, Germany E. Maccallini, P. Manini, F. Siviero SAES Getters S.p.A., Lainate, Italy
	Non Evaporable Getter pumps have been used since four decades in various scientific and industrial Ultra High and Extremely Ultra High Vacuum applications. For the majority of applications properties like high pumping speed vs. small size, powerless operation and hydrocarbon cleanliness are main aspects for the usage. In addition to this a growing number of applications nowadays also require particle free systems. In this paper we report on investigations on in-vacuum particle creation during the conditioning and activation process of CapaciTorr pumps.
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WEPVA049	Vacuum- and Bake-Out-Testbenches for the HESR at FAIR	3366
	H. Jagdfeld, M. Bai, U. Bechstedt, N. Bongers, P. Chaumet, F.M. Esser, F. Jordan, F. Klehr, G. Langenberg, G. Natour, U. Pabst, D. Prasuhn, L. Semke, F. Zahariev FZJ, Jülich, Germany
	The High-Energy Storage Ring (HESR) is one part of the international Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt. Forschungszentrum Jülich (IKP and ZEA-1) is responsible for the design and development of the HESR. The HESR is designed for antiprotons and heavy ion experiments as well. Therefore the vacuum is required to be 10^-11 mbar or better. To achieve this also in the curved sections, where 44 bent dipole magnets are installed, NEG coated dipole chambers will be used to reach the needed pumping speed and capacity. For activation of the NEG a bake-out system is needed. Two test benches were installed to investigate the required equipment needed to reach this low pressure: A vacuum test bench to investigate the influence of different types and quantity of vacuum pumps for the straight sections of the HESR A bake-out test bench for checking the achievable end pressure and develop the bake-out system for the NEG coated dipole chambers in the curved sections of the HESR The results of the tests and the bake-out concept including the layout of the control system and the special design of the heater jackets inside the dipoles and quadrupoles are presented. 1 Central Institute of Engineering, Electronics and Analytics- Engineering and Technology ZEA-1 2 Institute for nuclear physics
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WEPVA050	Developments for the Injection Kicker Vacuum System of the HESR at FAIR	3369
	F. Zahariev, M. Bai, N. Bongers, P. Chaumet, F.M. Esser, R. Gebel, H. Glückler, S. Hamzic, H. Jagdfeld, B. Laatsch, W. Lesmeister, L. Reifferscheidt, M. Retzlaff, L. Semke, R. Tölle FZJ, Jülich, Germany G. Natour Forschungszentrum Jülich GmbH, Central Institute of Engineering, Electronics and Analytics, Jülich, Germany
	The Research Center Jülich has taken the leadership of a consortium being responsible for the design and manufacturing of the High-Energy Storage Ring (HESR) going to be part of FAIR. The HESR is designed both for antiprotons and for heavy ion experiments. The injection kicker system of the HESR is located directly behind the septum and consists of two pumping crosses for pumps and measurement devices as well as two vacuum tanks housing the four ferrite magnets which will be operated with 40 kV, 4kA. As well as the magnets, the adjustments frames and the electrical feedthroughs will be installed inside the tanks. Due to the large surface of the magnets the injection kicker system will be very sensitive with regard to the achievable vacuum quality that is expected to be in the order of 10^-11 mbar or better. Thus the vacuum system is designed to heat up to 250°C. In order to investigate the achievable end pressure and to develop the heating system a test facility was constructed. The actual vacuum layout of the injection kicker system as well as the experimental test results will be presented and in similar the layout of the control system of the test facility will be described.
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WEPVA058	Development of HOM Absorber for SuperKEKB	3394
	S. Terui, T. Ishibashi, Y. Suetsugu, Y. Takeuchi, K. Watanabe KEK, Ibaraki, Japan H. Ishizaki, A. Kimura, T. Sawhata Metal Technology Co. Ltd., Ibaraki, Japan
	Higher-order modes (HOM) absorbers are necessary components for recent high-power accelerators in order to prevent beam instabilities (e.g. HOM- Beam Break Up instabilities) or the overheating of vacuum components. Several kinds of absorber materials, such as SiC, ferrite and Kanthal, have been investigated and applied in accelerators. Among these materials, ferrite has been found to be superior to others because of its higher HOM absorbing efficiency. However, because of its low tensile strength and small thermal expansion rate, it cannot be easily bonded to other metals thus limiting its use as a HOM absorber. We reported the success of the fabrication of ferrite-copper-blocks using the spark plasma sintering (SPS)-technique last year. This year we report testing with a high-power RF source and measuring gas desorption rate after baking and secondary electron yield.
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WEPVA062	Improvements of Vacuum System in J-PARC 3 GeV Synchrotron	3408
	J. Kamiya, Y. Hikichi, M. Kinsho, Y. Namekawa, K. Takeishi, T. Yanagibashi JAEA/J-PARC, Tokai-mura, Japan A. Sato Nippon Advanced Technology Co., Ltd., Tokai, Japan
	The RCS vacuum system has been upgraded since the completion of its construction towards the objectives of both better vacuum quality and higher reliability of the components. For the better vacuum quality, (1) pressure of the injection beam line was improved to prevent the H⁻ beam from converting to H0; (2) leakage in the beam injection area due to the thermal expansion was eliminated by applying the adequate torque amount for the clamps; (3) new in-situ degassing method of the kicker magnet was developed. For the reliability increase of the components, (1) A considerable number of fluoroelastmer seal was exchanged to metal seal with the low spring constant bellows and the light clamps; (2) TMP controller for the long cable was developed to prevent the controller failure by the severe electrical noise; (3) A number of TMP were installed instead of ion pumps in the RF cavity section as an insurance for the case of pump trouble.
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WEPVA090	The Vacuum System of MAX IV Storage Rings: Installation and Conditioning	3468
	E. Al-Dmour, M.J. Grabski MAX IV Laboratory, Lund University, Lund, Sweden
	The installation of the vacuum system of the 3 GeV storage ring was started in November 2014 and finished in May 2015. In August 2015 the commissioning of the storage ring started, the first stored beam has been achieved on the 15th of September 2015. The installation of the vacuum system of the 1.5 GeV storage ring was done from September 2015 and the main part finished in December 2015, the connection to the Linac with the transfer line has been done in August 2016. In September 2016 the commissioning of the 1.5 GeV storage ring started with the first stored beam achieved on the 30th of September 2016. The vacuum system conditioning for the two rings was successful; the average dynamic pressure reduction and the increase in the lifetime with the accumulated beam dose is a demonstration of the good performance of the vacuum system. The installation procedure and the results of the conditioning together with the latest developments are introduced here.
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WEPVA121	Thermal Experimet Results on TPS Beam Position Monitors	3554
	Y.T. Huang, C.K. Chan, J. -Y. Chuang, I.C. Sheng, Y.C. Yang NSRRC, Hsinchu, Taiwan
	Beam position monitors mounted in straight sections exhibit an unusual temperature rise which is attributed to poor thermal and electrical conductivity of the stainless steel BPM chamber, to the vicinity to RF-bellows, and the large button electrode size to get superior signal levels. Thermocouples tied to BPM flanges and RF bellows show that the temperature could reach 50 oC when storing a beam current of 400 mA and BPMs located between two RF-bellows in RF cavity sections responds by even 5-10 oC higher values than average. To resolve this issue, off site experiments and simulations were conducted to further understand the heat flow in the whole structure. In this paper we discuss more details of these studies.
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WEPVA122	Two Year Operational Experience With the Tps Vacuum System	3557
	Y.C. Yang, C.K. Chan, J. -Y. Chuang, Y.T. Huang, C.C. Liang, I.C. Sheng NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS), a 3-GeV third generation synchrotron light source, was commissioned in 2014 December and is now currently operated in top-up mode at 300mA for users. During the past two years, the machine was completed to meet design goals with among others the installation of superconducting cavities (SRF), the installation of insertion devices (ID) and the correction of vacuum chamber structure downstream from the IDs. The design goal of 500mA beam current was achieved with a total accumulated beam dose of more than 1000Ah, resulting in three orders of magnitude reduction of out-gassing. As the beam current was increased, a few vacuum problems were encountered, including vacuum leaks, unexpected pressure bursts, etc. Vacuum related issues including high pressure events, lessons learned and operational experience will be presented and discussed in this paper.
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WEPVA136	Vacuum System for the Diamond Light Source DDBA Upgrade	3587
	M.P. Cox, M.J. Duignan, R. Howard, S.C. Lay, A.G. Miller, H.S. Shiers, A. Wolfenden DLS, Oxfordshire, United Kingdom
	One cell of the Diamond Light Source (Diamond) storage ring was upgraded in late 2016 to a Double Double Bend Achromat (DDBA) configuration to provide an additional mid-achromat insertion device straight. For practical reasons it was decided to use discrete non-evaporable getter (NEG) pumps rather than NEG coatings. This paper outlines the vacuum design of the up-grade, the reasons for the choices made and the vacuum simulation tools used as well as describing the vacuum system engineering, assembly, installation and commissioning. The measured vacuum performance is found to be in close agreement with the simulations and a simple expression is derived for the beam gas lifetime.
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WEPVA137	Progress on the Design of the Storage Ring Vacuum System for the Advanced Photon Source Upgrade Project	3590
	B.K. Stillwell, B. Billett, B. Brajuskovic, J.A. Carter, E.S. Kirkus, M.A. Lale, J.E. Lerch, J. R. Noonan, M.M. O'Neill, B.G. Rocke, K.J. Suthar, D.R. Walters, G.E. Wiemerslage, J. Zientek ANL, Argonne, Illinois, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Recent work on the design of the storage ring vacuum system for the Advanced Photon Source Upgrade project (APS-U) includes: revising the vacuum system design to accommodate a new lattice with reverse bend magnets, modifying the designs of vacuum chambers in the FODO sections for more intense incident synchrotron radiation power, modifying the design of rf-shielding bellows liners for better performance and reliability, modifying photon absorber designs to make better use of available space, and integrated planning of components needed in the injection, extraction, and rf cavity straight sections. An overview of progress in these areas is presented.
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WEPVA146	Vacuum System Design and Simulation for CHESS-U	3612
	Y. Li, S.T. Barrett, D.C. Burke, J.V. Conway, X. Liu, A. Lyndaker Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by National Science Foundation Reward #DMR-1332208 A major upgrade project (dubbed CHESS-U) is planned to elevate performance of Cornell High Energy Synchrotron Source (CHESS) to the state-of-art 3rd generation light sources. In the project, about 80-m of Cornell Electron Storage Ring (CESR) will be replaced with double-bend achromat (DBA) lattice to reduce electron beam emittance. In this presentation, we will describe designs of the CHESS-U vacuum system, including new beam pipe extrusions and chambers, sliding joints, and crotch absorbers. Vacuum pumping system consists of distributed pumps (in the form of NEG strips) in the dipole chambers, and compact discrete NEG/Ion pumps in the quad straight and undulator beampipes. MolFlow+ is used to evaluate pumping performances of the CHESS-U vacuum system. First, we demonstrate that the planned vacuum pumping system can achieve and sustain required ultra-high vacuum level in CHESS-U operations, after an initial beam conditioning. Second, we will explore beam commissioning processes of the new vacuum chambers, and simulate the saturation of the NEG strips during the commissioning. These simulations will aid continuing design optimization for the CHESS-U vacuum pumping system.
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FRXAB1	Accelerator Vacuum Technology Challenges for Next-Generation Synchrotron-Light Sources	4830
	P. He IHEP, Beijing, People's Republic of China
	The development trend of future next-generation synchrotron light source storage rings is a compact lattice combined with small magnet apertures. This leads to important engineering challenges for the design and performance of a vacuum system because of lack of space, conductance limitation and high precision and stability positioning requirements. The speaker will review some possible solutions including the use of distributed pumping (NEG coating), distributed absorber (good thermal conducting material vacuum chamber wall), and distributed cooling (different water cooling channel design at the location where the synchrotron radiation hits the wall). In situ baking for NEG activation and precise installation will also be covered.
	Slides FRXAB1 [3.627 MB]
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Paper

Title

Page

Amorphous Carbon Thin Film Coating of the SPS Beamline: Evaluation of the First Coating Implementation

44

M. Van Gompel, P. Chiggiato, P. Costa Pinto, P. Cruikshank, C. Pasquino, J. Perez Espinos, A. Sapountzis, M. Taborelli, W. Vollenberg
CERN, Geneva, Switzerland

As part of the LHC Injector Upgrade (LIU) project, the Super Proton Synchrotron (SPS) must be upgraded in order to inject in the LHC 25 ns bunch spaced beams of higher intensity. To mitigate the Electron Multipacting (EM) phenomenon in the SPS, CERN developed thin film carbon coatings with a low Secondary Electron Yield (SEY). The development went from coating small samples, up to coating of 6 m long vacuum chambers directly installed in the magnets. To deposit the low SEY amorphous carbon (aC) film on the vacuum chamber inner wall of SPS ring components, a modular hollow cathode train was designed. The minimization of the logistical impact requires a strategy combining in-situ and ex-situ coating, depending on the type of components. To validate the implementation strategy of the aC thin films and the in-situ coating process along the 7 km long SPS beamline, approximately 2 cells of B-type bending dipoles and 9 focussing quadrupoles are foreseen to be treated with the aC coating during the Extended Year End Technical Stop (EYETS) 2016-2017. We will discuss the coating technique and evaluate both the implementation process and the resulting coating performance.

Slides MOOCA3 [71.421 MB]

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WEPIK025

Spectral Diagnostics of Argon Plasma in a 10mm Aperture Plasma Window

2978

P.P. Gan, S. Huang, Y.R. Lu, S.Z. Wang, Z.X. Yuan, K. Zhu
PKU, Beijing, People's Republic of China

A 10 mm diameter 60 mm long plasma window has been designed and managed to generate arc discharge with argon gas experimentally in Peking University. Based on the previous experiments and simulations, we have measured the electron temperature and density of the plasma via argon spectral diagnostics, and analyzed the conditions to satisfy the criterion of local thermal equilibrium (L.T.E). The electron temperature is in the range of 12000 K to 16000 K. The electron density is in the range of 2.2×10¹⁶ cm^-3 to 3.2×10¹⁶ cm^-3, increasing with discharge current and gas flow rate. The results indicate that our argon plasma is in the L.T.E status. The sealing pressure characteristics of the plasma window is mentioned as well.

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WEPIK107

Comparison Studies of Graphene Sey Results in NSRL and DL

3196

J. Wang, Y. Wang, B. Zhang, Y.X. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China
B.S. Sian, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
P.V. Tyagi
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
R. Valizadeh, G.X. Xia
Cockcroft Institute, Warrington, Cheshire, United Kingdom
G.X. Xia
UMAN, Manchester, United Kingdom
G.L. Yu
University of Manchester, Manchester, United Kingdom

Graphene has many excellent properties, such as high electron carrier mobility, good thermal conductivity and transparency etc. The secondary electron yield (SEY) of graphene with copper substrate had been studied in National Synchrotron Radiation Laboratory (NSRL) of China. The results show that the maximum SEY ('max) of 6~8 layers graphene film with copper substrates is about 1.25. Further studies indicate that many factors can affect the SEY test results. The recent SEY tests of graphene films with copper substrates in Daresbury Laboratory (DL) of UK gave the maximum SEY of as-received copper, graphene samples with copper substrates are 1.89, 1.83, and 1.68, respectively, under the incident charge per unit surface (Q) of 7.6×10^-8 C 'mm-2. Meanwhile, the SEY test parameters and measurement results of graphene in both laboratories are compared and analysed. The effect of defects on the SEY results of graphene films with copper substrate is also discussed.

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WEPVA043

Study of the Suitability of 3D Printing for Ultra-High Vacuum Applications

3356

S. Jenzer, M. Alves, N. Delerue, A. Gonnin, D. Grasset, F. Letellier-Cohen, B. Mercier, E. Mistretta, C. Prevost
LAL, Orsay, France
A. Vion
BV Proto, Sévenans, France
J-P. Wilmes
AGS Fusion, Izernore, France

Funding: IN2P3/CNRS
In the recent year additive fabrication (3D printing) has revolutionized mechanical engineering by allowing the quick production of mechanical components with complex shapes. So far most of these components are made in plastic and therefore can not be used in accelerator beam pipes. We have investigated samples printed using a metal 3D printer to study their behavior under vacuum. We report on our first tests showing that such samples are vacuum compatible and comparing pumping time.

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WEPVA048

Particle Generation of CapaciTorr Pumps

3363

S. Lederer, L. Lilje
DESY, Hamburg, Germany
E. Maccallini, P. Manini, F. Siviero
SAES Getters S.p.A., Lainate, Italy

Non Evaporable Getter pumps have been used since four decades in various scientific and industrial Ultra High and Extremely Ultra High Vacuum applications. For the majority of applications properties like high pumping speed vs. small size, powerless operation and hydrocarbon cleanliness are main aspects for the usage. In addition to this a growing number of applications nowadays also require particle free systems. In this paper we report on investigations on in-vacuum particle creation during the conditioning and activation process of CapaciTorr pumps.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA048

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WEPVA049

Vacuum- and Bake-Out-Testbenches for the HESR at FAIR

3366

H. Jagdfeld, M. Bai, U. Bechstedt, N. Bongers, P. Chaumet, F.M. Esser, F. Jordan, F. Klehr, G. Langenberg, G. Natour, U. Pabst, D. Prasuhn, L. Semke, F. Zahariev
FZJ, Jülich, Germany

The High-Energy Storage Ring (HESR) is one part of the international Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt. Forschungszentrum Jülich (IKP and ZEA-1) is responsible for the design and development of the HESR. The HESR is designed for antiprotons and heavy ion experiments as well. Therefore the vacuum is required to be 10^-11 mbar or better. To achieve this also in the curved sections, where 44 bent dipole magnets are installed, NEG coated dipole chambers will be used to reach the needed pumping speed and capacity. For activation of the NEG a bake-out system is needed. Two test benches were installed to investigate the required equipment needed to reach this low pressure: A vacuum test bench to investigate the influence of different types and quantity of vacuum pumps for the straight sections of the HESR A bake-out test bench for checking the achievable end pressure and develop the bake-out system for the NEG coated dipole chambers in the curved sections of the HESR The results of the tests and the bake-out concept including the layout of the control system and the special design of the heater jackets inside the dipoles and quadrupoles are presented.
1 Central Institute of Engineering, Electronics and Analytics- Engineering and Technology ZEA-1
2 Institute for nuclear physics

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WEPVA050

Developments for the Injection Kicker Vacuum System of the HESR at FAIR

3369

F. Zahariev, M. Bai, N. Bongers, P. Chaumet, F.M. Esser, R. Gebel, H. Glückler, S. Hamzic, H. Jagdfeld, B. Laatsch, W. Lesmeister, L. Reifferscheidt, M. Retzlaff, L. Semke, R. Tölle
FZJ, Jülich, Germany
G. Natour
Forschungszentrum Jülich GmbH, Central Institute of Engineering, Electronics and Analytics, Jülich, Germany

The Research Center Jülich has taken the leadership of a consortium being responsible for the design and manufacturing of the High-Energy Storage Ring (HESR) going to be part of FAIR. The HESR is designed both for antiprotons and for heavy ion experiments. The injection kicker system of the HESR is located directly behind the septum and consists of two pumping crosses for pumps and measurement devices as well as two vacuum tanks housing the four ferrite magnets which will be operated with 40 kV, 4kA. As well as the magnets, the adjustments frames and the electrical feedthroughs will be installed inside the tanks. Due to the large surface of the magnets the injection kicker system will be very sensitive with regard to the achievable vacuum quality that is expected to be in the order of 10^-11 mbar or better. Thus the vacuum system is designed to heat up to 250°C. In order to investigate the achievable end pressure and to develop the heating system a test facility was constructed. The actual vacuum layout of the injection kicker system as well as the experimental test results will be presented and in similar the layout of the control system of the test facility will be described.

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WEPVA058

Development of HOM Absorber for SuperKEKB

3394

S. Terui, T. Ishibashi, Y. Suetsugu, Y. Takeuchi, K. Watanabe
KEK, Ibaraki, Japan
H. Ishizaki, A. Kimura, T. Sawhata
Metal Technology Co. Ltd., Ibaraki, Japan

Higher-order modes (HOM) absorbers are necessary components for recent high-power accelerators in order to prevent beam instabilities (e.g. HOM- Beam Break Up instabilities) or the overheating of vacuum components. Several kinds of absorber materials, such as SiC, ferrite and Kanthal, have been investigated and applied in accelerators. Among these materials, ferrite has been found to be superior to others because of its higher HOM absorbing efficiency. However, because of its low tensile strength and small thermal expansion rate, it cannot be easily bonded to other metals thus limiting its use as a HOM absorber. We reported the success of the fabrication of ferrite-copper-blocks using the spark plasma sintering (SPS)-technique last year. This year we report testing with a high-power RF source and measuring gas desorption rate after baking and secondary electron yield.

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WEPVA062

Improvements of Vacuum System in J-PARC 3 GeV Synchrotron

3408

J. Kamiya, Y. Hikichi, M. Kinsho, Y. Namekawa, K. Takeishi, T. Yanagibashi
JAEA/J-PARC, Tokai-mura, Japan
A. Sato
Nippon Advanced Technology Co., Ltd., Tokai, Japan

The RCS vacuum system has been upgraded since the completion of its construction towards the objectives of both better vacuum quality and higher reliability of the components. For the better vacuum quality, (1) pressure of the injection beam line was improved to prevent the H⁻ beam from converting to H0; (2) leakage in the beam injection area due to the thermal expansion was eliminated by applying the adequate torque amount for the clamps; (3) new in-situ degassing method of the kicker magnet was developed. For the reliability increase of the components, (1) A considerable number of fluoroelastmer seal was exchanged to metal seal with the low spring constant bellows and the light clamps; (2) TMP controller for the long cable was developed to prevent the controller failure by the severe electrical noise; (3) A number of TMP were installed instead of ion pumps in the RF cavity section as an insurance for the case of pump trouble.

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WEPVA090

The Vacuum System of MAX IV Storage Rings: Installation and Conditioning

3468

E. Al-Dmour, M.J. Grabski
MAX IV Laboratory, Lund University, Lund, Sweden

The installation of the vacuum system of the 3 GeV storage ring was started in November 2014 and finished in May 2015. In August 2015 the commissioning of the storage ring started, the first stored beam has been achieved on the 15th of September 2015. The installation of the vacuum system of the 1.5 GeV storage ring was done from September 2015 and the main part finished in December 2015, the connection to the Linac with the transfer line has been done in August 2016. In September 2016 the commissioning of the 1.5 GeV storage ring started with the first stored beam achieved on the 30th of September 2016. The vacuum system conditioning for the two rings was successful; the average dynamic pressure reduction and the increase in the lifetime with the accumulated beam dose is a demonstration of the good performance of the vacuum system. The installation procedure and the results of the conditioning together with the latest developments are introduced here.

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WEPVA121

Thermal Experimet Results on TPS Beam Position Monitors

3554

Y.T. Huang, C.K. Chan, J. -Y. Chuang, I.C. Sheng, Y.C. Yang
NSRRC, Hsinchu, Taiwan

Beam position monitors mounted in straight sections exhibit an unusual temperature rise which is attributed to poor thermal and electrical conductivity of the stainless steel BPM chamber, to the vicinity to RF-bellows, and the large button electrode size to get superior signal levels. Thermocouples tied to BPM flanges and RF bellows show that the temperature could reach 50 oC when storing a beam current of 400 mA and BPMs located between two RF-bellows in RF cavity sections responds by even 5-10 oC higher values than average. To resolve this issue, off site experiments and simulations were conducted to further understand the heat flow in the whole structure. In this paper we discuss more details of these studies.

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WEPVA122

Two Year Operational Experience With the Tps Vacuum System

3557

Y.C. Yang, C.K. Chan, J. -Y. Chuang, Y.T. Huang, C.C. Liang, I.C. Sheng
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS), a 3-GeV third generation synchrotron light source, was commissioned in 2014 December and is now currently operated in top-up mode at 300mA for users. During the past two years, the machine was completed to meet design goals with among others the installation of superconducting cavities (SRF), the installation of insertion devices (ID) and the correction of vacuum chamber structure downstream from the IDs. The design goal of 500mA beam current was achieved with a total accumulated beam dose of more than 1000Ah, resulting in three orders of magnitude reduction of out-gassing. As the beam current was increased, a few vacuum problems were encountered, including vacuum leaks, unexpected pressure bursts, etc. Vacuum related issues including high pressure events, lessons learned and operational experience will be presented and discussed in this paper.

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WEPVA136

Vacuum System for the Diamond Light Source DDBA Upgrade

3587

M.P. Cox, M.J. Duignan, R. Howard, S.C. Lay, A.G. Miller, H.S. Shiers, A. Wolfenden
DLS, Oxfordshire, United Kingdom

One cell of the Diamond Light Source (Diamond) storage ring was upgraded in late 2016 to a Double Double Bend Achromat (DDBA) configuration to provide an additional mid-achromat insertion device straight. For practical reasons it was decided to use discrete non-evaporable getter (NEG) pumps rather than NEG coatings. This paper outlines the vacuum design of the up-grade, the reasons for the choices made and the vacuum simulation tools used as well as describing the vacuum system engineering, assembly, installation and commissioning. The measured vacuum performance is found to be in close agreement with the simulations and a simple expression is derived for the beam gas lifetime.

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WEPVA137

Progress on the Design of the Storage Ring Vacuum System for the Advanced Photon Source Upgrade Project

3590

B.K. Stillwell, B. Billett, B. Brajuskovic, J.A. Carter, E.S. Kirkus, M.A. Lale, J.E. Lerch, J. R. Noonan, M.M. O'Neill, B.G. Rocke, K.J. Suthar, D.R. Walters, G.E. Wiemerslage, J. Zientek
ANL, Argonne, Illinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Recent work on the design of the storage ring vacuum system for the Advanced Photon Source Upgrade project (APS-U) includes: revising the vacuum system design to accommodate a new lattice with reverse bend magnets, modifying the designs of vacuum chambers in the FODO sections for more intense incident synchrotron radiation power, modifying the design of rf-shielding bellows liners for better performance and reliability, modifying photon absorber designs to make better use of available space, and integrated planning of components needed in the injection, extraction, and rf cavity straight sections. An overview of progress in these areas is presented.

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WEPVA146

Vacuum System Design and Simulation for CHESS-U

3612

Y. Li, S.T. Barrett, D.C. Burke, J.V. Conway, X. Liu, A. Lyndaker
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by National Science Foundation Reward #DMR-1332208
A major upgrade project (dubbed CHESS-U) is planned to elevate performance of Cornell High Energy Synchrotron Source (CHESS) to the state-of-art 3rd generation light sources. In the project, about 80-m of Cornell Electron Storage Ring (CESR) will be replaced with double-bend achromat (DBA) lattice to reduce electron beam emittance. In this presentation, we will describe designs of the CHESS-U vacuum system, including new beam pipe extrusions and chambers, sliding joints, and crotch absorbers. Vacuum pumping system consists of distributed pumps (in the form of NEG strips) in the dipole chambers, and compact discrete NEG/Ion pumps in the quad straight and undulator beampipes. MolFlow+ is used to evaluate pumping performances of the CHESS-U vacuum system. First, we demonstrate that the planned vacuum pumping system can achieve and sustain required ultra-high vacuum level in CHESS-U operations, after an initial beam conditioning. Second, we will explore beam commissioning processes of the new vacuum chambers, and simulate the saturation of the NEG strips during the commissioning. These simulations will aid continuing design optimization for the CHESS-U vacuum pumping system.

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FRXAB1

Accelerator Vacuum Technology Challenges for Next-Generation Synchrotron-Light Sources

4830

P. He
IHEP, Beijing, People's Republic of China

The development trend of future next-generation synchrotron light source storage rings is a compact lattice combined with small magnet apertures. This leads to important engineering challenges for the design and performance of a vacuum system because of lack of space, conductance limitation and high precision and stability positioning requirements. The speaker will review some possible solutions including the use of distributed pumping (NEG coating), distributed absorber (good thermal conducting material vacuum chamber wall), and distributed cooling (different water cooling channel design at the location where the synchrotron radiation hits the wall). In situ baking for NEG activation and precise installation will also be covered.

Slides FRXAB1 [3.627 MB]

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