IPAC2014 - Classification: 06 Instrumentation, Controls, Feedback & Operational Aspects / T17 Alignment and Survey

Paper	Title	Page
TUPRO065	Tests of Beam-based Alignment at FACET	1186
	A. Latina, J. Pfingstner, D. Schulte CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	Tests of Beam-Based Alignment have been performed at FACET, with successful results. A flight simulator based on PLACET has been put in place to test the correction algorithms before applying the correction to the real machine. The flight simulator not only helped studying the parameters space in a safe environment, but it also helped developing a graphical interface that the experimenter can use to set each parameter of the correction also during the on-line.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO065
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TUPRI088	Active Vibration Isolation System for CLIC Final Focus	1775
	G. Balik, N. Allemandou, J. Allibe, J.P. Baud, L. Brunetti, G. Deleglise, A. Jeremie, S. Vilalte IN2P3-LAPP, Annecy-le-Vieux, France B. Caron, C. Hernandez SYMME, Annecy-le-Vieux, France
	With pinpoint accuracy, the next generation of Linear Collider such as CLIC will collide electron and positron beams at a centre of mass energy of 3 TeV with a desired peak luminosity of 2*1034 cm^-2s⁻¹. One of the many challenging features of CLIC is its ability to collide beams at the sub-nanometer scale at the Interaction Point (IP). Such a high level of accuracy could only be achieved by integrating Active Vibration Isolation system (AVI) upstream the collision to prevent the main source of vibration; Ground Motion (GM). Complementary control systems downstream the collision (Interaction Point FeedBack (IPFB), Orbit FeedBack(OFB)) allow low frequency vibration rejection. This paper focus on a dedicated AVI table designed for the last focusing quadrupole QD0 where the specifications are the most stringent. Combining FeedForward (FF) and FeedBack (FB) techniques, the prototype is able to reduce GM down to 0.6 nm RMS(4Hz) experimentally without load. These performances couldn’t be achieved without cutting edge-technology such as sub-nanometer piezo actuator, ultra-low noise accelerometer and seismometers and an accurate guidance system. The whole AVI system is described in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI088
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TUPRI089	Numerical Technique for Nonlinear Beam-based Alignment	1778
	F. Guatieri, C. Milardi INFN/LNF, Frascati (Roma), Italy D. Orsucci UNIPI, Pisa, Italy
	Two techniques to perform Beam-Based Alignment are presented. These techniques are intended for the difficult case arising in circular accelerators characterized by a nonlinear dependence of the Response Matrix on misalignments of the magnetic sources, where the standard approach fails. The developed algorithms have been successfully used to reconstruct misalignments in the transverse position of the quadrupoles installed in the main rings of the DAΦNE collider.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI089
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TUPRI090	Linac Alignment for SuperKEKB Injector	1781
	T. Higo, K. Kakihara, T. Kamitani, M. Satoh, R. Sugahara, T. Suwada, M. Tanaka KEK, Ibaraki, Japan
	The misalignment of the linac beamline components amounted to be a millimeter level during the operation of KEKB, though the requirement of 0.1mm in mind. The limited effort toward improving such big misalignments has long been pursued but could not finish especially after the earthquake in March 2011. This linac is now under upgrade to the SuperKEKB, where the required alignment is 0.1mm in σ for the short distance in 100m span, while 0.3mm through the whole linac for the emittance preservation. The straight line as a reference for the alignment was defined by laser beam over 500m. The actual hardwares are set with respect to this reference line by using a laser tracker. The alignment present status is reported in this paper. On the other hand, we noticed, through the alignment measurements over months, that the tunnel floor moved in the range of 0.1mm or maybe more. The evaluation of this movement is on-going to discuss about how to achieve the required emittance and how to keep the situation. Various measurements to evaluate the movement are presented also in the paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI090
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TUPRI091	Refinement of ARC Alignment between Two Straight Sections for Injector Linac of SuperKEKB	1784
	M. Tanaka, T. Higo, K. Kakihara, T. Kamitani KEK, Ibaraki, Japan K. Kimura, K. Suzuki, N. Toyotomi, S. Ushimoto Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	The beam line of the KEKB injector linac is under realignment as the restoration after the big Earthquake in 2011, but with the refinement for the SuperKEKB in mind. The linac consists of two straight sections connected by a 180 degree ARC. Precise alignment of the ARC magnets is one of the key issues for the emittance preservation of the electron beam. The ARC beam line was defined by measuring these two straight lines. Then, the misalignment of the ARC magnets were reduced from 3 mm maximum down to 0.1mm in the errors perpendicular to the beam direction. This paper describes how we defined the ARC beam line and performed the alignment. The connection method of the laser tracker data needed for the definition of the ARC was also studied and described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI091
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TUPRI092	Improvement of the Position Monitor using White Light Interferometer for Measuring Precise Movement of Compact ERL Superconducting Cavities in Cryomodule	1787
	H. Sakai, K. Enami, T. Furuya, M. Satoh, K. Shinoe, K. Umemori KEK, Ibaraki, Japan T. Aoto, K. Hayashi, K. Kanzaki Tokyo Seimitsu Co. Ltd, Ibaraki, Japan E. Cenni Sokendai, Ibaraki, Japan M. Sawamura JAEA, Ibaraki-ken, Japan
	Alignment of superconducting cavities is one of the important issues for linear collider and/or future light source like ERL and X-FEL. To measure the cavity displacement under cooling to liquid He temperature more precisely, we newly developed the position monitor by using white light interferometer. This monitor is based on the measurement of the interference of light between the measurement target and the reference point. It can measure the position from the outside of the cryomodule. We applied this monitor to the main linac cryomodule of Compact ERL (cERL) and successfully measured the displacement during 2K cooling with the resolution of 10um. However, some drift come from outer temperature and humidity were observed. In this paper, we describe the upgraded version of this monitor to suppress these drift for cERL beam operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI092
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TUPRI093	Determination of the Magnetic Axis of a CLIC Drive Beam Quadrupole with respect to External Alignment Targets using a Combination of WPS, CMM and Laser Tracker Measurements.	1790
	M. Duquenne, M. Anastasopoulos, D. Caiazza, G. Deferne, J. Garcia Perez, H. Mainaud Durand, M. Modena, V. Rude, J. Sandomierski, M. Sosin CERN, Geneva, Switzerland
	CERN is currently studying the feasibility of building a high energy e⁺ e⁻ linear collider: the CLIC (Compact LInear Collider). One of the engineering challenges is the pre-alignment precision and accuracy requirement on the alignment of the linac components. For example, the magnetic axis of a Drive Beam Quadrupole will need to be aligned within 20 um rms with respect to a straight reference line of alignment. The fiducialisation process which is the determination of the magnetic axis with respect to external alignment targets, that is part of this error budget, will have to be performed at an accuracy never reached before. This paper presents the strategy proposed for the fiducialisation of the Drive Beam quadrupole, based on a combination of CMM measurements, WPS measurements and Laser tracker measurements. The results obtained on a dedicated test bench will be described as well.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI093
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TUPRI094	Experiments of Laser Pointing Stability in Air and in Vacuum to Validate Micrometric Positioning Sensor	1793
	G. Stern, H. Mainaud Durand, D. Piedigrossi, J. Sandomierski, M. Sosin CERN, Geneva, Switzerland A. Geiger, S. Guillaume ETH, Zurich, Switzerland
	Aligning accelerator components over 200m with 10 μm accuracy is a challenging task within the Compact Linear Collider (CLIC) study. A solution based on laser beam in vacuum as straight line reference is proposed. The positions of the accelerator’s components are measured with respect to the laser beam by sensors made of camera/shutter assemblies. To validate these sensors, laser pointing stability has to be studied over 200m. We perform experiments in air and in vacuum in order to know how laser pointing stability varies with the distance of propagation and with the environment. The experiments show that the standard deviations of the laser spot coordinates increase with the distance of propagation. They also show that the standard deviations are much smaller in vacuum (8 μm at 35m) than in air (2000 μm at 200m). Our experiment validates the concept of laser beam in vacuum with camera/shutter assembly for micrometric positioning over 35m. It also gives an estimation of the achievable precision.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI094
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TUPRI095	Design and Study on a 5 Degree-of-freedom Adjustment Platform for CLIC Drive Beam Quadrupoles	1796
	M. Sosin, M. Anastasopoulos, M. Duquenne, J. Kemppinen, H. Mainaud Durand, V. Rude, J. Sandomierski CERN, Geneva, Switzerland
	Since several years CERN is studying the feasibility of building a high energy e⁺ e⁻ linear collider: the CLIC (Compact LInear Collider). The pre-alignment precision and accuracy requirement for the transverse positions of the linac components is typically 14 micrometers over a sliding window of 200m. One of the challenges is precise adjustment of Drive Beam quadrupole’s magnetic axis. It has to be done with micrometric resolution along 5 DOF in a common support’s coordinate system. This paper describes the design and the study of a solution based on flexural components in a type of “Stewart Platform” configuration. The engineering approach, the lessons learned (“know how”), the issues of adjustment solution and the mechanical components behaviors are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI095
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Paper

Title

Page

Tests of Beam-based Alignment at FACET

1186

A. Latina, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

Tests of Beam-Based Alignment have been performed at FACET, with successful results. A flight simulator based on PLACET has been put in place to test the correction algorithms before applying the correction to the real machine. The flight simulator not only helped studying the parameters space in a safe environment, but it also helped developing a graphical interface that the experimenter can use to set each parameter of the correction also during the on-line.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO065

Export •

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

TUPRI088

Active Vibration Isolation System for CLIC Final Focus

1775

G. Balik, N. Allemandou, J. Allibe, J.P. Baud, L. Brunetti, G. Deleglise, A. Jeremie, S. Vilalte
IN2P3-LAPP, Annecy-le-Vieux, France
B. Caron, C. Hernandez
SYMME, Annecy-le-Vieux, France

With pinpoint accuracy, the next generation of Linear Collider such as CLIC will collide electron and positron beams at a centre of mass energy of 3 TeV with a desired peak luminosity of 2*1034 cm^-2s⁻¹. One of the many challenging features of CLIC is its ability to collide beams at the sub-nanometer scale at the Interaction Point (IP). Such a high level of accuracy could only be achieved by integrating Active Vibration Isolation system (AVI) upstream the collision to prevent the main source of vibration; Ground Motion (GM). Complementary control systems downstream the collision (Interaction Point FeedBack (IPFB), Orbit FeedBack(OFB)) allow low frequency vibration rejection. This paper focus on a dedicated AVI table designed for the last focusing quadrupole QD0 where the specifications are the most stringent. Combining FeedForward (FF) and FeedBack (FB) techniques, the prototype is able to reduce GM down to 0.6 nm RMS(4Hz) experimentally without load. These performances couldn’t be achieved without cutting edge-technology such as sub-nanometer piezo actuator, ultra-low noise accelerometer and seismometers and an accurate guidance system. The whole AVI system is described in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI088

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TUPRI089

Numerical Technique for Nonlinear Beam-based Alignment

1778

F. Guatieri, C. Milardi
INFN/LNF, Frascati (Roma), Italy
D. Orsucci
UNIPI, Pisa, Italy

Two techniques to perform Beam-Based Alignment are presented. These techniques are intended for the difficult case arising in circular accelerators characterized by a nonlinear dependence of the Response Matrix on misalignments of the magnetic sources, where the standard approach fails. The developed algorithms have been successfully used to reconstruct misalignments in the transverse position of the quadrupoles installed in the main rings of the DAΦNE collider.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI089

Export •

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

TUPRI090

Linac Alignment for SuperKEKB Injector

1781

T. Higo, K. Kakihara, T. Kamitani, M. Satoh, R. Sugahara, T. Suwada, M. Tanaka
KEK, Ibaraki, Japan

The misalignment of the linac beamline components amounted to be a millimeter level during the operation of KEKB, though the requirement of 0.1mm in mind. The limited effort toward improving such big misalignments has long been pursued but could not finish especially after the earthquake in March 2011. This linac is now under upgrade to the SuperKEKB, where the required alignment is 0.1mm in σ for the short distance in 100m span, while 0.3mm through the whole linac for the emittance preservation. The straight line as a reference for the alignment was defined by laser beam over 500m. The actual hardwares are set with respect to this reference line by using a laser tracker. The alignment present status is reported in this paper. On the other hand, we noticed, through the alignment measurements over months, that the tunnel floor moved in the range of 0.1mm or maybe more. The evaluation of this movement is on-going to discuss about how to achieve the required emittance and how to keep the situation. Various measurements to evaluate the movement are presented also in the paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI090

Export •

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

TUPRI091

Refinement of ARC Alignment between Two Straight Sections for Injector Linac of SuperKEKB

1784

M. Tanaka, T. Higo, K. Kakihara, T. Kamitani
KEK, Ibaraki, Japan
K. Kimura, K. Suzuki, N. Toyotomi, S. Ushimoto
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

The beam line of the KEKB injector linac is under realignment as the restoration after the big Earthquake in 2011, but with the refinement for the SuperKEKB in mind. The linac consists of two straight sections connected by a 180 degree ARC. Precise alignment of the ARC magnets is one of the key issues for the emittance preservation of the electron beam. The ARC beam line was defined by measuring these two straight lines. Then, the misalignment of the ARC magnets were reduced from 3 mm maximum down to 0.1mm in the errors perpendicular to the beam direction. This paper describes how we defined the ARC beam line and performed the alignment. The connection method of the laser tracker data needed for the definition of the ARC was also studied and described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI091

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

TUPRI092

Improvement of the Position Monitor using White Light Interferometer for Measuring Precise Movement of Compact ERL Superconducting Cavities in Cryomodule

1787

H. Sakai, K. Enami, T. Furuya, M. Satoh, K. Shinoe, K. Umemori
KEK, Ibaraki, Japan
T. Aoto, K. Hayashi, K. Kanzaki
Tokyo Seimitsu Co. Ltd, Ibaraki, Japan
E. Cenni
Sokendai, Ibaraki, Japan
M. Sawamura
JAEA, Ibaraki-ken, Japan

Alignment of superconducting cavities is one of the important issues for linear collider and/or future light source like ERL and X-FEL. To measure the cavity displacement under cooling to liquid He temperature more precisely, we newly developed the position monitor by using white light interferometer. This monitor is based on the measurement of the interference of light between the measurement target and the reference point. It can measure the position from the outside of the cryomodule. We applied this monitor to the main linac cryomodule of Compact ERL (cERL) and successfully measured the displacement during 2K cooling with the resolution of 10um. However, some drift come from outer temperature and humidity were observed. In this paper, we describe the upgraded version of this monitor to suppress these drift for cERL beam operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI092

Export •

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

TUPRI093

Determination of the Magnetic Axis of a CLIC Drive Beam Quadrupole with respect to External Alignment Targets using a Combination of WPS, CMM and Laser Tracker Measurements.

1790

M. Duquenne, M. Anastasopoulos, D. Caiazza, G. Deferne, J. Garcia Perez, H. Mainaud Durand, M. Modena, V. Rude, J. Sandomierski, M. Sosin
CERN, Geneva, Switzerland

CERN is currently studying the feasibility of building a high energy e⁺ e⁻ linear collider: the CLIC (Compact LInear Collider). One of the engineering challenges is the pre-alignment precision and accuracy requirement on the alignment of the linac components. For example, the magnetic axis of a Drive Beam Quadrupole will need to be aligned within 20 um rms with respect to a straight reference line of alignment. The fiducialisation process which is the determination of the magnetic axis with respect to external alignment targets, that is part of this error budget, will have to be performed at an accuracy never reached before. This paper presents the strategy proposed for the fiducialisation of the Drive Beam quadrupole, based on a combination of CMM measurements, WPS measurements and Laser tracker measurements. The results obtained on a dedicated test bench will be described as well.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI093

Export •

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

TUPRI094

Experiments of Laser Pointing Stability in Air and in Vacuum to Validate Micrometric Positioning Sensor

1793

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

Aligning accelerator components over 200m with 10 μm accuracy is a challenging task within the Compact Linear Collider (CLIC) study. A solution based on laser beam in vacuum as straight line reference is proposed. The positions of the accelerator’s components are measured with respect to the laser beam by sensors made of camera/shutter assemblies. To validate these sensors, laser pointing stability has to be studied over 200m. We perform experiments in air and in vacuum in order to know how laser pointing stability varies with the distance of propagation and with the environment. The experiments show that the standard deviations of the laser spot coordinates increase with the distance of propagation. They also show that the standard deviations are much smaller in vacuum (8 μm at 35m) than in air (2000 μm at 200m). Our experiment validates the concept of laser beam in vacuum with camera/shutter assembly for micrometric positioning over 35m. It also gives an estimation of the achievable precision.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI094

Export •

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

TUPRI095

Design and Study on a 5 Degree-of-freedom Adjustment Platform for CLIC Drive Beam Quadrupoles

1796

M. Sosin, M. Anastasopoulos, M. Duquenne, J. Kemppinen, H. Mainaud Durand, V. Rude, J. Sandomierski
CERN, Geneva, Switzerland

Since several years CERN is studying the feasibility of building a high energy e⁺ e⁻ linear collider: the CLIC (Compact LInear Collider). The pre-alignment precision and accuracy requirement for the transverse positions of the linac components is typically 14 micrometers over a sliding window of 200m. One of the challenges is precise adjustment of Drive Beam quadrupole’s magnetic axis. It has to be done with micrometric resolution along 5 DOF in a common support’s coordinate system. This paper describes the design and the study of a solution based on flexural components in a type of “Stewart Platform” configuration. The engineering approach, the lessons learned (“know how”), the issues of adjustment solution and the mechanical components behaviors are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI095

Export •

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