IPAC2012 - List of Authors (Sterbini, G.)

Paper	Title	Page
TUPPR031	Experimental Verification of the CLIC Decelerator with theTest Beam Line in the CLIC Test Facility 3	1885
	R.L. Lillestøl, S. Döbert, M. Olvegård, A. Rabiller, G. Sterbini CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The Test Beam Line in the CLIC Test Facility 3 is the first prototype of the CLIC drive beam decelerator. The main purpose of the experiment is to demonstrate efficient 12 GHz rf power production and stable transport of an electron drive beam during deceleration. The Test Beam Line consists of a FODO structure with high precision BPMs and quadrupoles mounted on mechanical movers for precise beam alignment. Nine out of the planned 16 Power Extraction and Transfer Structures have currently been installed and commissioned. We correlate rf power production measurements with the drive beam deceleration measurements, and compare the two measurements to the theoretical predictions. We also discuss the impact of the drive beam bunch length and bunch combination on the measurements.

TUPPR034	Beam-based Alignment in CTF3 Test Beam Line	1894
	G. Sterbini, S. Döbert, R.L. Lillestøl, E. Marín, D. Schulte CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The CLIC linear collider is based on the two beams acceleration scheme. During acceleration, the drive beam suffers a large increase in its energy spread. In order to efficiently transport such a beam, beam-based alignment techniques together with tight pre-alignment tolerances are crucial. A beam-based steering campaign has been conducted at the Test Beam Line of the CLIC Test Facility to evaluate the performance of several algorithms. In the following we present and discuss the obtained results.

TUPPR035	A Comparative Study for the CLIC Drive Beam Decelerator Optics	1897
	G. Sterbini, D. Schulte CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The baseline for the CLIC drive beam decelerators optics consists of a 2-m-long FODO cell. This solution was adopted to have strong focusing in order to mitigate the effect of the PETS wakefields and to minimize the drive beam envelope. Taking into account the most recent PETS design, we compare the performance of the baseline FODO cell with a proposal that consider twice longer FODO cell. Despite of the expected cost in term of performance, the reduction of the complexity of the system due to the halving of the number of quadrupoles can be beneficial for the overall optimization of the decelerator design.

WEPPD073	Strategy and Validation of Fiducialization for the Pre-alignment of CLIC Components	2693
	S. griffet, A. Cherif, J. Kemppinen, H. Mainaud Durand, V. Rude, G. Sterbini CERN, Geneva, Switzerland
	The feasibility of the high energy e⁺ e⁻ linear collider CLIC (Compact Linear Collider) is very dependent on the ability to accurately pre-align its components. There are two 20-km-long Main Linacs which meet in an interaction point (IP). The Main Linacs are composed of thousands of 2 m long modules. One of the challenges is to meet very tight alignment tolerances at the level of CLIC module: for example, the center of a Drive Beam Quad needs to be aligned within 20 μm rms with respect to a straight line. Such accuracies cannot be achieved using usual measurement devices. Thus it is necessary to work in close collaboration with the metrology lab. To test and improve many critical points, including alignment, a CLIC mock-up is being assembled at CERN. This paper describes the application of the strategy of fiducialization for the pre-alignment of CLIC mock-up components. It also deals with the first results obtained by performing measurements using a CMM (Coordinate Measuring Machine) to ensure the fiducialization, using a Laser Tracker to adjust or check components’ positions on a girder and finally using a Measuring Arm to perform dimensional control after assembling steps.

WEPPD074	Issues and Feasibility Demonstration of Positioning Closed Loop Control for the CLIC Supporting System Using a Test Mock-up with Five Degrees of Freedom	2696
	M. Sosin, M. Anastasopoulos, N. Chritin, J. Kemppinen, H. Mainaud Durand, V. Rude, G. Sterbini, S. griffet 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). One of the challenges of such a collider is the pre-alignment precision and accuracy requirement on the transverse positions of the linac components, which is typically 14 μm over a window of 200 m. To ensure the possibility of positioning within such tight constraints, CERN Beams Department’s Survey team has worked intensively at developing the methods and technology needed to achieve that objective. This paper describes activities which were performed on a test bench (mock-up) with five degrees of freedom (DOF) for the qualification of control algorithms for the CLIC supporting system active-pre-alignment. Present understanding, lessons learned (“know how”), issues of sensors noise and mechanical components nonlinearities are presented.

Paper

Title

Page

Experimental Verification of the CLIC Decelerator with theTest Beam Line in the CLIC Test Facility 3

1885

R.L. Lillestøl, S. Döbert, M. Olvegård, A. Rabiller, G. Sterbini
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The Test Beam Line in the CLIC Test Facility 3 is the first prototype of the CLIC drive beam decelerator. The main purpose of the experiment is to demonstrate efficient 12 GHz rf power production and stable transport of an electron drive beam during deceleration. The Test Beam Line consists of a FODO structure with high precision BPMs and quadrupoles mounted on mechanical movers for precise beam alignment. Nine out of the planned 16 Power Extraction and Transfer Structures have currently been installed and commissioned. We correlate rf power production measurements with the drive beam deceleration measurements, and compare the two measurements to the theoretical predictions. We also discuss the impact of the drive beam bunch length and bunch combination on the measurements.

TUPPR034

Beam-based Alignment in CTF3 Test Beam Line

1894

G. Sterbini, S. Döbert, R.L. Lillestøl, E. Marín, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The CLIC linear collider is based on the two beams acceleration scheme. During acceleration, the drive beam suffers a large increase in its energy spread. In order to efficiently transport such a beam, beam-based alignment techniques together with tight pre-alignment tolerances are crucial. A beam-based steering campaign has been conducted at the Test Beam Line of the CLIC Test Facility to evaluate the performance of several algorithms. In the following we present and discuss the obtained results.

TUPPR035

A Comparative Study for the CLIC Drive Beam Decelerator Optics

1897

G. Sterbini, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The baseline for the CLIC drive beam decelerators optics consists of a 2-m-long FODO cell. This solution was adopted to have strong focusing in order to mitigate the effect of the PETS wakefields and to minimize the drive beam envelope. Taking into account the most recent PETS design, we compare the performance of the baseline FODO cell with a proposal that consider twice longer FODO cell. Despite of the expected cost in term of performance, the reduction of the complexity of the system due to the halving of the number of quadrupoles can be beneficial for the overall optimization of the decelerator design.

WEPPD073

Strategy and Validation of Fiducialization for the Pre-alignment of CLIC Components

2693

S. griffet, A. Cherif, J. Kemppinen, H. Mainaud Durand, V. Rude, G. Sterbini
CERN, Geneva, Switzerland

The feasibility of the high energy e⁺ e⁻ linear collider CLIC (Compact Linear Collider) is very dependent on the ability to accurately pre-align its components. There are two 20-km-long Main Linacs which meet in an interaction point (IP). The Main Linacs are composed of thousands of 2 m long modules. One of the challenges is to meet very tight alignment tolerances at the level of CLIC module: for example, the center of a Drive Beam Quad needs to be aligned within 20 μm rms with respect to a straight line. Such accuracies cannot be achieved using usual measurement devices. Thus it is necessary to work in close collaboration with the metrology lab. To test and improve many critical points, including alignment, a CLIC mock-up is being assembled at CERN. This paper describes the application of the strategy of fiducialization for the pre-alignment of CLIC mock-up components. It also deals with the first results obtained by performing measurements using a CMM (Coordinate Measuring Machine) to ensure the fiducialization, using a Laser Tracker to adjust or check components’ positions on a girder and finally using a Measuring Arm to perform dimensional control after assembling steps.

WEPPD074

Issues and Feasibility Demonstration of Positioning Closed Loop Control for the CLIC Supporting System Using a Test Mock-up with Five Degrees of Freedom

2696

M. Sosin, M. Anastasopoulos, N. Chritin, J. Kemppinen, H. Mainaud Durand, V. Rude, G. Sterbini, S. griffet
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). One of the challenges of such a collider is the pre-alignment precision and accuracy requirement on the transverse positions of the linac components, which is typically 14 μm over a window of 200 m. To ensure the possibility of positioning within such tight constraints, CERN Beams Department’s Survey team has worked intensively at developing the methods and technology needed to achieve that objective. This paper describes activities which were performed on a test bench (mock-up) with five degrees of freedom (DOF) for the qualification of control algorithms for the CLIC supporting system active-pre-alignment. Present understanding, lessons learned (“know how”), issues of sensors noise and mechanical components nonlinearities are presented.