IPAC2017 - Classification: 07 Accelerator Technology / T19 Collimation

Paper	Title	Page
WEPIK009	Collimators for SuperKEKB Main Ring	2929
	T. Ishibashi, Y. Suetsugu, S. Terui KEK, Ibaraki, Japan
	SuperKEKB, which is an upgrade project of KEKB, is an electron-positron collider with extremely high luminosity. Collimators (movable masks) for SuperKEKB have been designed to fit an antechamber scheme of the vacuum system and will be operated to improve backgrounds in the particle detector named Belle II. We are developing two types of collimators; a horizontal and vertical collimator. The collimator has a pair of horizontally or vertically opposed movable jaws with RF fingers. Each jaw travels independently through 5-25 mm horizontally or 2-12 mm vertically in a distance between the beam axis and the tip of the jaw. SuperKEKB will operate with high currents of short bunch lengths, therefore it is important to estimate and decrease the impedance of the collimators. Two horizontal collimators were already installed in the positron ring and operated during Phase-1 commissioning for approximately 5 months, from February to June 2016. In this presentation, the latest design, and the results in the Phase-1 commissioning are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK009
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WEPVA070	Alignment and Calibration for Collimation System in CSNS/RCS	3432
	J.B. Yu, L. Dong, L. Kang, B. Li, X.J. Nie, A.X. Wang, G.Y. Wang, X.L. Wang, J.S. Zhang IHEP, Beijing, People's Republic of China J.X. Chen, T. Luo, C.J. Ning CSNS, Guangdong Province, People's Republic of China
	Funding: National Natural Science Foundation of China (Grant Nos.11375217) In order to reduce the uncontrolled losses in the localized station, the beam collimation system has been performed for the 1.6GeV synchrotron of CSNS. The CSNS/RCS transverse collimation system is designed to be a two-stage system which consists of one primary collimator and four secondary collimators. All collimators had completed processing and now been installed in the tunnel. To meet the requirements of physical system, alignment for collimation system have to be done before circulating beams. This paper will show the alignment technique of collimation system. Then some problems during the alignment process will be mentioned. For the primary collimator will be replaced in second-stage of CSNS, and the alignment for the replaced collimator will be introduced finally.
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WEPVA108	Operational Feedback and Analysis of Current and Future Designs of the Injection Protection Absorbers in the Large Hadron Collider at CERN	3517
	D. Carbajo Perez, N. Biancacci, C. Bracco, G. Bregliozzi, M. Calviani, M.I. Frankl, L. Gentini, S.S. Gilardoni, G. Iadarola, I. Lamas Garcia, A. Lechner, A. Perillo-Marcone, B. Salvant CERN, Geneva, Switzerland
	Two injection protection absorbers, so-called TDIs (Target Dump Injection), are installed close to Interaction Points IP2 and IP8 of the Large Hadron Collider (LHC) right downstream of the injection kicker magnets (MKI). Malfunction or timing errors in the latter lead to wrong steering of the beam, which must then be intercepted by the TDI to avoid downstream equipment (which includes superconducting magnets) damage. In recent years, MKI failures during operation have brought to light opportunities for improvement of the TDI. The upgrade of this absorber, so-called TDIS (where S stands for segmented), is conceived as part of the High Luminosity-LHC (HL-LHC) project and those operational issues are taken into account for its design. The present document describes not only the aspects related to the current TDI performance and their impact in its successor's design but also the key modifications to cope with the stronger requirements associated to the higher luminosity goal.
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WEPVA113	Thermo-Physical and Mechanical Characterisation of Novel Materials under Development for HL-LHC Beam Intercepting Devices	3536
	O. Sacristan De Frutos, A. Bertarelli, L. Bianchi, F. Carra, J. Guardia, M. Guinchard, S. Redaelli CERN, Geneva, Switzerland
	Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD-2, grant agreement no.312453 The collimation system for high energy particle accelerators as HL-LHC, must be designed to withstand the close interaction with intense and energetic particle beams, safely operating over an extended range of temperatures in extreme conditions (pressure, strain-rate, radiation), which are to become more demanding with the High Luminosity LHC. In order to withstand such conditions, the candidate materials must possess among other properties outstanding thermal shock resistance and high thermal and electrical conductivity, condition only met by advanced or novel materials. Therefore, an extensive R&D program has been launched to develop novel materials capable of replacing or complementing materials used for present collimators. So far, Molybdenum Carbide - Graphite and Copper-Diamond composites have been identified as the most promising materials. Literature data are scarce or non-existing for these materials. For this reason the successive characterisation campaigns constitute a linchpin of the R&D program. This paper reviews the experimental program followed for the thermo-physical and mechanical characterisation of the materials, and discusses the most relevant results.
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WEPVA117	Preliminary Mechanical Design Study of the Hollow Electron Lens for HL-LHC	3547
	C. Zanoni, G. Gobbi, D. Perini CERN, Geneva, Switzerland G. Stancari Fermilab, Batavia, Illinois, USA
	A Hollow Electron Lens has been proposed in order to improve performance of halo control and collimation in the Large Hadron Collider in view of its High Luminosity upgrade (HL-LHC). The concept is based on a beam of electrons that travels around the protons for a few meters. The electron beam is produced by a cathode and then guided by a strong magnetic field generated by a set of solenoids. Mechanical design and integration require a preliminary knowledge of the optimal configuration of the solenoids that drive the electron trajectories. The estimation of such trajectories by means of a dedicated Matlab tool is presented. The influence of the main geometrical and electrical parameters is analysed and discussed. The main mechanical design choices are also outlined along with the concept of the electron collector. The aim of this paper is to provide an overview of the feasibility study of the Electron Lens for LHC. The methods used in this study also serve as examples for future mechanical and integration designs of similar devices.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA117
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Paper

Title

Page

Collimators for SuperKEKB Main Ring

2929

T. Ishibashi, Y. Suetsugu, S. Terui
KEK, Ibaraki, Japan

SuperKEKB, which is an upgrade project of KEKB, is an electron-positron collider with extremely high luminosity. Collimators (movable masks) for SuperKEKB have been designed to fit an antechamber scheme of the vacuum system and will be operated to improve backgrounds in the particle detector named Belle II. We are developing two types of collimators; a horizontal and vertical collimator. The collimator has a pair of horizontally or vertically opposed movable jaws with RF fingers. Each jaw travels independently through 5-25 mm horizontally or 2-12 mm vertically in a distance between the beam axis and the tip of the jaw. SuperKEKB will operate with high currents of short bunch lengths, therefore it is important to estimate and decrease the impedance of the collimators. Two horizontal collimators were already installed in the positron ring and operated during Phase-1 commissioning for approximately 5 months, from February to June 2016. In this presentation, the latest design, and the results in the Phase-1 commissioning are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK009

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WEPVA070

Alignment and Calibration for Collimation System in CSNS/RCS

3432

J.B. Yu, L. Dong, L. Kang, B. Li, X.J. Nie, A.X. Wang, G.Y. Wang, X.L. Wang, J.S. Zhang
IHEP, Beijing, People's Republic of China
J.X. Chen, T. Luo, C.J. Ning
CSNS, Guangdong Province, People's Republic of China

Funding: National Natural Science Foundation of China (Grant Nos.11375217)
In order to reduce the uncontrolled losses in the localized station, the beam collimation system has been performed for the 1.6GeV synchrotron of CSNS. The CSNS/RCS transverse collimation system is designed to be a two-stage system which consists of one primary collimator and four secondary collimators. All collimators had completed processing and now been installed in the tunnel. To meet the requirements of physical system, alignment for collimation system have to be done before circulating beams. This paper will show the alignment technique of collimation system. Then some problems during the alignment process will be mentioned. For the primary collimator will be replaced in second-stage of CSNS, and the alignment for the replaced collimator will be introduced finally.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA070

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPVA108

Operational Feedback and Analysis of Current and Future Designs of the Injection Protection Absorbers in the Large Hadron Collider at CERN

3517

D. Carbajo Perez, N. Biancacci, C. Bracco, G. Bregliozzi, M. Calviani, M.I. Frankl, L. Gentini, S.S. Gilardoni, G. Iadarola, I. Lamas Garcia, A. Lechner, A. Perillo-Marcone, B. Salvant
CERN, Geneva, Switzerland

Two injection protection absorbers, so-called TDIs (Target Dump Injection), are installed close to Interaction Points IP2 and IP8 of the Large Hadron Collider (LHC) right downstream of the injection kicker magnets (MKI). Malfunction or timing errors in the latter lead to wrong steering of the beam, which must then be intercepted by the TDI to avoid downstream equipment (which includes superconducting magnets) damage. In recent years, MKI failures during operation have brought to light opportunities for improvement of the TDI. The upgrade of this absorber, so-called TDIS (where S stands for segmented), is conceived as part of the High Luminosity-LHC (HL-LHC) project and those operational issues are taken into account for its design. The present document describes not only the aspects related to the current TDI performance and their impact in its successor's design but also the key modifications to cope with the stronger requirements associated to the higher luminosity goal.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA108

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WEPVA113

Thermo-Physical and Mechanical Characterisation of Novel Materials under Development for HL-LHC Beam Intercepting Devices

3536

O. Sacristan De Frutos, A. Bertarelli, L. Bianchi, F. Carra, J. Guardia, M. Guinchard, S. Redaelli
CERN, Geneva, Switzerland

Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD-2, grant agreement no.312453
The collimation system for high energy particle accelerators as HL-LHC, must be designed to withstand the close interaction with intense and energetic particle beams, safely operating over an extended range of temperatures in extreme conditions (pressure, strain-rate, radiation), which are to become more demanding with the High Luminosity LHC. In order to withstand such conditions, the candidate materials must possess among other properties outstanding thermal shock resistance and high thermal and electrical conductivity, condition only met by advanced or novel materials. Therefore, an extensive R&D program has been launched to develop novel materials capable of replacing or complementing materials used for present collimators. So far, Molybdenum Carbide - Graphite and Copper-Diamond composites have been identified as the most promising materials. Literature data are scarce or non-existing for these materials. For this reason the successive characterisation campaigns constitute a linchpin of the R&D program. This paper reviews the experimental program followed for the thermo-physical and mechanical characterisation of the materials, and discusses the most relevant results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA113

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WEPVA117

Preliminary Mechanical Design Study of the Hollow Electron Lens for HL-LHC

3547

C. Zanoni, G. Gobbi, D. Perini
CERN, Geneva, Switzerland
G. Stancari
Fermilab, Batavia, Illinois, USA

A Hollow Electron Lens has been proposed in order to improve performance of halo control and collimation in the Large Hadron Collider in view of its High Luminosity upgrade (HL-LHC). The concept is based on a beam of electrons that travels around the protons for a few meters. The electron beam is produced by a cathode and then guided by a strong magnetic field generated by a set of solenoids. Mechanical design and integration require a preliminary knowledge of the optimal configuration of the solenoids that drive the electron trajectories. The estimation of such trajectories by means of a dedicated Matlab tool is presented. The influence of the main geometrical and electrical parameters is analysed and discussed. The main mechanical design choices are also outlined along with the concept of the electron collector. The aim of this paper is to provide an overview of the feasibility study of the Electron Lens for LHC. The methods used in this study also serve as examples for future mechanical and integration designs of similar devices.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA117

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