IPAC2016 - Classification: 06 Beam Instrumentation, Controls, Feedback and Operational Aspects / T17 Alignment and Survey

Paper	Title	Page
MOOCB01	PACMAN Project: A New Solution for the High-accuracy Alignment of Accelerator Components	58
	H. Mainaud Durand, K. Artoos, M.C.L. Buzio, D. Caiazza, N. Catalán Lasheras, A. Cherif, I.P. Doytchinov, J.-F. Fuchs, A. Gaddi, N. Galindo Munoz, J. Gayde, S.W. Kamugasa, M. Modena, P. Novotny, S. Russenschuck, C. Sanz, G. Severino, D. Tshilumba, V. Vlachakis, M. Wendt, S. Zorzetti CERN, Geneva, Switzerland
	The beam alignment requirements for the next generation of lepton colliders have become increasingly challenging. As an example, the alignment requirements for the three major collider components of the CLIC linear collider are as follows. Before the first beam circulates, the Beam Position Monitors (BPM), Accelerating Structures (AS)and quadrupoles will have to be aligned up to 10 μm w.r.t. a straight line over 200 m long segments, along the 20 km of linacs. PACMAN is a study on Particle Accelerator Components' Metrology and Alignment to the Nanometre scale. It is an Innovative Doctoral Program, funded by the EU and hosted by CERN, providing high quality training to 10 Early Stage Researchers working towards a PhD thesis. The technical aim of the project is to improve the alignment accuracy of the CLIC components by developing new methods and tools addressing several steps of alignment simultaneously, to gain time and accuracy. The tools and methods developed will be validated on a test bench. This paper presents the technical systems to be integrated in the test bench, the results of the compatibility tests performed between these systems, as well as the final design of the PACMAN validation bench.
	Slides MOOCB01 [9.553 MB]
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WEPMR012	Misalignment Studies of LCLS-II SC Linac	2283
	A. Saini, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA T.O. Raubenheimer SLAC, Menlo Park, California, USA
	The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of a 4 GeV superconducting (SC) linear accelerator (linac). An optimal reliable performance of the linac is largely determined by beam sensitivity to various component alignment errors. In this paper we evaluate misalignment tolerances of LCLSII SC linac using a more realistic alignment model that includes correlated misalignment of elements.
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WEPOR011	Lattice Matching with Elegant at ELSA	2690
	J.-P. Thiry, W. Hillert ELSA, Bonn, Germany
	The electron stretcher ring ELSA provides a beam of polarized electrons of up to 3.2 GeV energy. To preserve the initial degree of polarization, several depolarizing resonances have to be compensated during the fast energy ramp of 6 GeV/s. Beam depolarization, caused by crossing these resonances is studied using comprehensive numerical calculations. These depend essentially on a precise model of the actual magnetic field distributions, explicitly taking into account misalignments. Hence it is necessary to match the theoretical lattice to the actual accelerator. In a first step the alignment of all magnets has been examined and improved. This was done by using standard survey equipment and precise electronic spirit levels. In a second step the concept of response matrix fitting is used for further, beam based, lattice matching. Particle tracking and optics calculations are carried out using elegant, a fully 6D accelerator toolbox. Lattice matching is done by repeatedly calling elegant and utilizing a modified Levenberg-Marquardt optimizer. In this contribution we will describe our lattice fitting implementation.
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WEPOR015	Introduction to WPS System Designed to Measure the Change of Location for PAL-XFEL Girder	2693
	H. J. Choi, K.H. Gil, H.-S. Kang, H.-G. Lee, S.B. Lee, K.W. Seo PAL, Pohang, Kyungbuk, Republic of Korea
	To maintain stable electron beam parameters (Energy 10GeV, Charge 200pC, Bunch Length 60fs, Emittance X/Y 0.481um/0.256um), PAL-XFEL equipment should keep the alignment of accelerator (±100um) and undulator (±50um) constant. To ensure the precise measurement and alignment of PAL-XFEL, GPS-based surface geodetic network and the installation of a tunnel measurement network inside buildings was prepared and the fiducialization of major equipment was completed. After PAL-XFEL equipment is aligned, if the ground and buildings go through vertical changes during operation, tilt and misalignment of equipments (correct magnet, BPM, accelerator) will cause errors in the electron beam trajectory, which will lead to changes in the beam parameter. Hydrostatic Levelling System (HLS) was installed to measure vertical changes in buildings and the ground (sinking and uplifting) continuously and systematically, and Wire Position System (WPS) installed to measure changes in Girder. This paper introduces the operation principle, design concept, installation status, and operation status of WPS.
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WEPOR016	Pre-alignment of Accelerating Structures for Compact Acceleration and High Gradient using In-situ Radiofrequency Methods	2696
SUPSS078	use link to see paper's listing under its alternate paper code
	N. Galindo Munoz, N. Catalán Lasheras, A. Grudiev CERN, Geneva, Switzerland V.E. Boria DCOM-iTEAM-UPV, Valencia, Spain A. Faus-Golfe IFIC, Valencia, Spain
	Funding: PACMAN is founded under the European Union's 7th Framework Program Marie Curie Actions, grant PITN-GA-2013-606839 To achieve a high accelerating gradient of 100 MV/m, the CLIC project under study at CERN uses a 23 cm long tapered normal-conducting travelling wave Accelerating Structure (AS) operating at 12 GHz. Minimisation of the long-range wakefields (WF) is assured by damping of the HOM through four radial waveguides in each cell without distorting the accelerating mode. As an extension of them, there are four bent waveguides called WF monitors (WFM) in the middle cell with two RF pick-ups. To obtain a small beam emittance in the collision point, micro-metric pre-alignment of the AS is required. We work to find the electrical centre of the AS through the use of the asymmetry in the RF scattering parameters created by an off-centre conductive wire, stretched along the axis. The accuracy required is of 7 μm with a resolution of 3.5 μm for the WFM signals including the acquisition electronics. Our simulations have shown that a resolution of 1 μm is possible using a calibrated VNA. Measurement results and improvements of the final accuracy will be presented and discussed.
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WEPOR017	A Micrometric Positioning Sensor for Laser-Based Alignment	2700
	G. Stern, H. Mainaud Durand, D. Piedigrossi, M. Sosin CERN, Geneva, Switzerland A. Geiger, S. Guillaume ETH, Zurich, Switzerland
	The Compact Linear Collider requires 10 μm accuracy over 200m for the alignment of its components. Since current techniques based on stretched wire or water level are difficult to implement, other options are under study. We propose a laser alignment system using positioning sensors made of camera/shutter assemblies. The goal is to implement such a positioning sensor. The corresponding studies comprise design and calibration as well as investigations of measurement accuracy and precision. On the one hand, we describe mathematically the laser beam propagation, its interaction with the shutter and image processing. On the other hand, we present experiments done with the prototype of a positioning sensor. As a result, we give practical suggestions to build the positioning sensors and we describe a calibration protocol to be applied to all sensors before measuring. In addition, we deliver estimates for measurement accuracy and precision. Our work provides the first steps towards a full alignment system.
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WEPOR018	Position Monitoring System for HL-LHC Crab Cavities	2704
	M. Sosin, T. Dijoud, H. Mainaud Durand CERN, Geneva, Switzerland V. Rude ESGT-CNAM, Le Mans, France
	The high luminosity upgrade for the LHC at CERN (HL-LHC project) will extend the discovery potential of the LHC by a factor 10. It relies on key innovative technologies like superconducting cavities for beam rotation, named 'crab cavities'. Two crab cavities will be hosted in a superconducting cryostat working at a cold (<3 K). The position of each cavity will be monitored during the cool-down and the operation in order to comply with the tight alignment tolerances: the misalignment of a cavity axis w.r.t. the other will have to be lower than 0.5 mm and each cavity roll w.r.t. the cryostat axis will have to be lower than 1 mrad. Moreover, the monitoring system will have to be radiation hard (up to 10 MGy) and maintenance free. We propose a solution based on the Frequency Scanning Interferometry to provide the position monitoring of the crab cavities. This paper describes the design and study of such a solution, including the engineering approach, the issues encountered and the lessons learnt.
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WEPOR057	A Mass Spectrometer for Measuring a High Current Ion Beam With a Big Range of the Charge-to-Mass Ratio	2799
	Z. Bowen, S. An PLAI, Nanjing, People's Republic of China L. Zhang Chang'an University, Chang'an, People's Republic of China
	In order to analyze a high-current mixed-ion beam's physical properties with a current of 100 mA and a charge-to-mass ratio range from 1:1 to 1:48, a mass spectrometer has been developed to measure the beam's current, profile and ratio of the different ions by Nanjing University and Andesun Technology Inc. The main part of the mass spectrometer is a mass analyzer, which is used to measure the different ion's beam current at the same time. This paper introduces the design of the mass analyzer.
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WEPOW032	Impact of the DBA Blocks Alignment on the Beam Dynamics of the Storage Ring in Solaris	2902
	J.J. Wiechecki, C.J. Bocchetta, M. Boruchowski, P. Król, A.I. Wawrzyniak Solaris, Kraków, Poland K. Karaś, A.M. Marendziak, R. Nietubyć Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland
	Installation of the Solaris synchrotron has been accomplished at the beginning of the 2015. Although the machine is a replica of the 1.5 GeV ring at MAX IV in Sweden, the entire group responsible for the installation, was facing numerous problems during the entire installation period. One of the most critical issues that are responsible for the proper functionality of the machine is the survey of the machine. An appropriate alignment of the components in accordance to each other as also to the building, provides a good quality of the beam so extensively desired by the beamline's users. This paper presents the results of the alignment in the 1.5 GeV ring, describes possible critical sectors of the ring that might influence the accuracy of the measurements and juxtapose the results with the values gained during the operational phase of the synchrotron. This comparison enables the identification of the beam losses and extension of the lifetime of the electron beam.
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

PACMAN Project: A New Solution for the High-accuracy Alignment of Accelerator Components

58

H. Mainaud Durand, K. Artoos, M.C.L. Buzio, D. Caiazza, N. Catalán Lasheras, A. Cherif, I.P. Doytchinov, J.-F. Fuchs, A. Gaddi, N. Galindo Munoz, J. Gayde, S.W. Kamugasa, M. Modena, P. Novotny, S. Russenschuck, C. Sanz, G. Severino, D. Tshilumba, V. Vlachakis, M. Wendt, S. Zorzetti
CERN, Geneva, Switzerland

The beam alignment requirements for the next generation of lepton colliders have become increasingly challenging. As an example, the alignment requirements for the three major collider components of the CLIC linear collider are as follows. Before the first beam circulates, the Beam Position Monitors (BPM), Accelerating Structures (AS)and quadrupoles will have to be aligned up to 10 μm w.r.t. a straight line over 200 m long segments, along the 20 km of linacs. PACMAN is a study on Particle Accelerator Components' Metrology and Alignment to the Nanometre scale. It is an Innovative Doctoral Program, funded by the EU and hosted by CERN, providing high quality training to 10 Early Stage Researchers working towards a PhD thesis. The technical aim of the project is to improve the alignment accuracy of the CLIC components by developing new methods and tools addressing several steps of alignment simultaneously, to gain time and accuracy. The tools and methods developed will be validated on a test bench. This paper presents the technical systems to be integrated in the test bench, the results of the compatibility tests performed between these systems, as well as the final design of the PACMAN validation bench.

Slides MOOCB01 [9.553 MB]

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WEPMR012

Misalignment Studies of LCLS-II SC Linac

2283

A. Saini, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
T.O. Raubenheimer
SLAC, Menlo Park, California, USA

The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of a 4 GeV superconducting (SC) linear accelerator (linac). An optimal reliable performance of the linac is largely determined by beam sensitivity to various component alignment errors. In this paper we evaluate misalignment tolerances of LCLSII SC linac using a more realistic alignment model that includes correlated misalignment of elements.

Export •

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

WEPOR011

Lattice Matching with Elegant at ELSA

2690

J.-P. Thiry, W. Hillert
ELSA, Bonn, Germany

The electron stretcher ring ELSA provides a beam of polarized electrons of up to 3.2 GeV energy. To preserve the initial degree of polarization, several depolarizing resonances have to be compensated during the fast energy ramp of 6 GeV/s. Beam depolarization, caused by crossing these resonances is studied using comprehensive numerical calculations. These depend essentially on a precise model of the actual magnetic field distributions, explicitly taking into account misalignments. Hence it is necessary to match the theoretical lattice to the actual accelerator. In a first step the alignment of all magnets has been examined and improved. This was done by using standard survey equipment and precise electronic spirit levels. In a second step the concept of response matrix fitting is used for further, beam based, lattice matching. Particle tracking and optics calculations are carried out using elegant, a fully 6D accelerator toolbox. Lattice matching is done by repeatedly calling elegant and utilizing a modified Levenberg-Marquardt optimizer. In this contribution we will describe our lattice fitting implementation.

Export •

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

WEPOR015

Introduction to WPS System Designed to Measure the Change of Location for PAL-XFEL Girder

2693

H. J. Choi, K.H. Gil, H.-S. Kang, H.-G. Lee, S.B. Lee, K.W. Seo
PAL, Pohang, Kyungbuk, Republic of Korea

To maintain stable electron beam parameters (Energy 10GeV, Charge 200pC, Bunch Length 60fs, Emittance X/Y 0.481um/0.256um), PAL-XFEL equipment should keep the alignment of accelerator (±100um) and undulator (±50um) constant. To ensure the precise measurement and alignment of PAL-XFEL, GPS-based surface geodetic network and the installation of a tunnel measurement network inside buildings was prepared and the fiducialization of major equipment was completed. After PAL-XFEL equipment is aligned, if the ground and buildings go through vertical changes during operation, tilt and misalignment of equipments (correct magnet, BPM, accelerator) will cause errors in the electron beam trajectory, which will lead to changes in the beam parameter. Hydrostatic Levelling System (HLS) was installed to measure vertical changes in buildings and the ground (sinking and uplifting) continuously and systematically, and Wire Position System (WPS) installed to measure changes in Girder. This paper introduces the operation principle, design concept, installation status, and operation status of WPS.

Export •

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

WEPOR016

Pre-alignment of Accelerating Structures for Compact Acceleration and High Gradient using In-situ Radiofrequency Methods

2696

SUPSS078

use link to see paper's listing under its alternate paper code

N. Galindo Munoz, N. Catalán Lasheras, A. Grudiev
CERN, Geneva, Switzerland
V.E. Boria
DCOM-iTEAM-UPV, Valencia, Spain
A. Faus-Golfe
IFIC, Valencia, Spain

Funding: PACMAN is founded under the European Union's 7th Framework Program Marie Curie Actions, grant PITN-GA-2013-606839
To achieve a high accelerating gradient of 100 MV/m, the CLIC project under study at CERN uses a 23 cm long tapered normal-conducting travelling wave Accelerating Structure (AS) operating at 12 GHz. Minimisation of the long-range wakefields (WF) is assured by damping of the HOM through four radial waveguides in each cell without distorting the accelerating mode. As an extension of them, there are four bent waveguides called WF monitors (WFM) in the middle cell with two RF pick-ups. To obtain a small beam emittance in the collision point, micro-metric pre-alignment of the AS is required. We work to find the electrical centre of the AS through the use of the asymmetry in the RF scattering parameters created by an off-centre conductive wire, stretched along the axis. The accuracy required is of 7 μm with a resolution of 3.5 μm for the WFM signals including the acquisition electronics. Our simulations have shown that a resolution of 1 μm is possible using a calibrated VNA. Measurement results and improvements of the final accuracy will be presented and discussed.

Export •

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

WEPOR017

A Micrometric Positioning Sensor for Laser-Based Alignment

2700

G. Stern, H. Mainaud Durand, D. Piedigrossi, M. Sosin
CERN, Geneva, Switzerland
A. Geiger, S. Guillaume
ETH, Zurich, Switzerland

The Compact Linear Collider requires 10 μm accuracy over 200m for the alignment of its components. Since current techniques based on stretched wire or water level are difficult to implement, other options are under study. We propose a laser alignment system using positioning sensors made of camera/shutter assemblies. The goal is to implement such a positioning sensor. The corresponding studies comprise design and calibration as well as investigations of measurement accuracy and precision. On the one hand, we describe mathematically the laser beam propagation, its interaction with the shutter and image processing. On the other hand, we present experiments done with the prototype of a positioning sensor. As a result, we give practical suggestions to build the positioning sensors and we describe a calibration protocol to be applied to all sensors before measuring. In addition, we deliver estimates for measurement accuracy and precision. Our work provides the first steps towards a full alignment system.

Export •

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

WEPOR018

Position Monitoring System for HL-LHC Crab Cavities

2704

M. Sosin, T. Dijoud, H. Mainaud Durand
CERN, Geneva, Switzerland
V. Rude
ESGT-CNAM, Le Mans, France

The high luminosity upgrade for the LHC at CERN (HL-LHC project) will extend the discovery potential of the LHC by a factor 10. It relies on key innovative technologies like superconducting cavities for beam rotation, named 'crab cavities'. Two crab cavities will be hosted in a superconducting cryostat working at a cold (<3 K). The position of each cavity will be monitored during the cool-down and the operation in order to comply with the tight alignment tolerances: the misalignment of a cavity axis w.r.t. the other will have to be lower than 0.5 mm and each cavity roll w.r.t. the cryostat axis will have to be lower than 1 mrad. Moreover, the monitoring system will have to be radiation hard (up to 10 MGy) and maintenance free. We propose a solution based on the Frequency Scanning Interferometry to provide the position monitoring of the crab cavities. This paper describes the design and study of such a solution, including the engineering approach, the issues encountered and the lessons learnt.

Export •

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

WEPOR057

A Mass Spectrometer for Measuring a High Current Ion Beam With a Big Range of the Charge-to-Mass Ratio

2799

Z. Bowen, S. An
PLAI, Nanjing, People's Republic of China
L. Zhang
Chang'an University, Chang'an, People's Republic of China

In order to analyze a high-current mixed-ion beam's physical properties with a current of 100 mA and a charge-to-mass ratio range from 1:1 to 1:48, a mass spectrometer has been developed to measure the beam's current, profile and ratio of the different ions by Nanjing University and Andesun Technology Inc. The main part of the mass spectrometer is a mass analyzer, which is used to measure the different ion's beam current at the same time. This paper introduces the design of the mass analyzer.

Export •

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

WEPOW032

Impact of the DBA Blocks Alignment on the Beam Dynamics of the Storage Ring in Solaris

2902

J.J. Wiechecki, C.J. Bocchetta, M. Boruchowski, P. Król, A.I. Wawrzyniak
Solaris, Kraków, Poland
K. Karaś, A.M. Marendziak, R. Nietubyć
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland

Installation of the Solaris synchrotron has been accomplished at the beginning of the 2015. Although the machine is a replica of the 1.5 GeV ring at MAX IV in Sweden, the entire group responsible for the installation, was facing numerous problems during the entire installation period. One of the most critical issues that are responsible for the proper functionality of the machine is the survey of the machine. An appropriate alignment of the components in accordance to each other as also to the building, provides a good quality of the beam so extensively desired by the beamline's users. This paper presents the results of the alignment in the 1.5 GeV ring, describes possible critical sectors of the ring that might influence the accuracy of the measurements and juxtapose the results with the values gained during the operational phase of the synchrotron. This comparison enables the identification of the beam losses and extension of the lifetime of the electron beam.

Export •

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