IPAC2013 - List of Authors (Bambade, P.)

Paper

Title

Page

Development of Diamond Sensors for Beam Halo and Compton Spectrum Diagnostics After The Interaction Point of ATF2

470

S. Liu, P. Bambade
LAL, Orsay, France
S. Bai
IHEP, Beijing, People's Republic of China
T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan

ATF2 is a low energy (1.3GeV) prototype of the final focus system for ILC and CLIC linear collider projects. A major issue at ATF2 and in linear colliders is to control the beam halo, which consists of tails extending far beyond the Gaussian core of the beam. At present there is no dedicated collimation for the beam halo at ATF2, and the transverse distribution near the interaction point is not well known. The development of a sensor based on CVD diamond to scan the beam halo in the vacuum chamber a few meters after the interaction point is presented. This system also aims to detect the Compton recoil electrons generated by the laser interferometer (Shintake monitor) used to measure the beam size at the interaction point of ATF2.

MOPME004

Fast Luminosity Monitoring using Diamond Sensors for Super Flavour Factories

473

C. Rimbault, P. Bambade
LAL, Orsay, France

Super flavour factories aim to reach very high luminosities thanks to a new concept whereby the ultra-low emittance beams collide with a large crossing angle. Fast luminosity measurements are needed as input to luminosity optimization and feedback in the presence of dynamic imperfections. The required small relative precision can be reached exploiting the very large cross section of the radiative Bhabha process at zero photon scattering angle. The instrumental technique selected to sustain the large particle fluxes is based on diamond sensors to be positioned via moveable stages immediately outside the beam pipe, at locations chosen to minimize the contamination from other particle loss mechanisms.

TUOCB203

In Vacuum High Accuracy Mechanical Positioning System of Nano Resolution Beam Position Monitor at the Interaction Point of ATF2

1149

P. Bambade, O.R. Blanco, F. Bogard, P. Cornebise, S. Wallon
LAL, Orsay, France
T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan

ATF2 is a low energy (1.3GeV) prototype of the final focus system for ILC and CLIC linear collider projects. A major goal of ATF2 is to demonstrate the ability to stabilise the beam position at the interaction point, where the beam can be focused down to about 35 nm. For this purpose, a set of new Beam Position Monitors (BPM) has been designed, with an expected resolution of about 2 nm. These BPMs must be very well aligned with respect to the beam, at the few micron level, to fully exploit their fine resolution. In this paper, the mechanical positioning system which has been developed to enable such a precise alignment is presented. It is based on a set of eight piezo actuators with nanometer range displacement resolution, mounted in a new specially made vacuum chamber. Due to the expected resolution of the piezo actuators, this system also brings a new functionality, the possibility to calibrate the BPMs by mechanically scanning the beam.

Slides TUOCB203 [2.276 MB]

TUPME024

Re-optimization of the Final Focus System Optics with Vertical Chromatic Correction

1622

Y. Wang, J. Gao
IHEP, Beijing, People's Republic of China
P. Bambade
LAL, Orsay, France

Funding: The France China Particle Physics Laboratory (FCPPL) and The National Natural Science Foundation of China (NSFC, Project 11175192)
The purpose of the final focus (FF) system of the future linear collider (ILC and CLIC) is to demagnify the beam to the required size at the IP. This can be done in a compact way based on a local chromaticity correction. Two important issues are beam-beam induced radiation effects and the optical correction strategy to mitigate static and dynamic imperfections. For a small enough beam energy spread, we investigate the possibility to get a smaller vertical beam size, at the expense of a larger horizontal beam size, by re-optimising the final focus optics with chromatic correction mainly in the vertical plane. Firstly, we track the beam with MAD-X, with and without chromaticity correction, to estimate the optimum betax and betay values by rematching the linear optics, and cross-check and improve the rematching procedure with MAPCLASS. Then, we study the original design and an alternative simplified optical system, using a set of enlarged betax values, and optimize the sextupoles as a function of betay to minimize the vertical beam size for different assumptions on the energy spread.

TUPWO003

CLIC 3 TeV Beam Size Optimization with Radiation Effects

1877

O.R. Blanco, P. Bambade
LAL, Orsay, France
R. Tomás
CERN, Geneva, Switzerland

Horizontal beamsize contribution due to radiation on bending magnets is calculated using theoretical results and recent improvements in mapclass (Mapclass2). In order to verify the code and validity of its approximations, a simple lattice with no geometrical nor chromatic aberrations, one dipole and a final drift has been used to compare Mapclass2 calculations and Placet tracking results. CLIC 3TeV lattice is optimized including the radiation effects. Current results show that correction of chromatic aberrations impose constraints in radiation improvement.

TUPWO017

Simulation on the Breaking of αx Multiknob Orthogonality in the Presence of Gradient and Coupling Errors and Experimental Investigation

1919

S. Bai, J. Gao
IHEP, Beijing, People's Republic of China
P. Bambade
LAL, Orsay, France
G.R. White
SLAC, Menlo Park, California, USA

The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. In beam tuning towards the goal beam size, the presence of a tilt of the IP Shintake monitor fringe pattern with respect to the x-y coordinate system of the beam can break the orthogonality in the main σ34 and σ32 waist corrections required to reduce the vertical beam size at IP. Concerning the method of doing αx scan and measuring the vertical beam size to diagnose the IPBSM fringe tilt or residual σ13, one thing should be studied is to check what could break the orthogonality of the αx knob other than σ13 and the IPBSM fringe tilt. In this paper, we report on the simulation study that check for the breaking of orthogonality of the αx knob in the presence of gradient and coupling errors; to what extent this breaking of orthogonality can go; and also calculate the IPBSM fringe tilt angle from experiment results.

Paper	Title	Page
MOPME003	Development of Diamond Sensors for Beam Halo and Compton Spectrum Diagnostics After The Interaction Point of ATF2	470
	S. Liu, P. Bambade LAL, Orsay, France S. Bai IHEP, Beijing, People's Republic of China T. Tauchi, N. Terunuma KEK, Ibaraki, Japan
	ATF2 is a low energy (1.3GeV) prototype of the final focus system for ILC and CLIC linear collider projects. A major issue at ATF2 and in linear colliders is to control the beam halo, which consists of tails extending far beyond the Gaussian core of the beam. At present there is no dedicated collimation for the beam halo at ATF2, and the transverse distribution near the interaction point is not well known. The development of a sensor based on CVD diamond to scan the beam halo in the vacuum chamber a few meters after the interaction point is presented. This system also aims to detect the Compton recoil electrons generated by the laser interferometer (Shintake monitor) used to measure the beam size at the interaction point of ATF2.

MOPME004	Fast Luminosity Monitoring using Diamond Sensors for Super Flavour Factories	473
	C. Rimbault, P. Bambade LAL, Orsay, France
	Super flavour factories aim to reach very high luminosities thanks to a new concept whereby the ultra-low emittance beams collide with a large crossing angle. Fast luminosity measurements are needed as input to luminosity optimization and feedback in the presence of dynamic imperfections. The required small relative precision can be reached exploiting the very large cross section of the radiative Bhabha process at zero photon scattering angle. The instrumental technique selected to sustain the large particle fluxes is based on diamond sensors to be positioned via moveable stages immediately outside the beam pipe, at locations chosen to minimize the contamination from other particle loss mechanisms.

TUOCB203	In Vacuum High Accuracy Mechanical Positioning System of Nano Resolution Beam Position Monitor at the Interaction Point of ATF2	1149
	P. Bambade, O.R. Blanco, F. Bogard, P. Cornebise, S. Wallon LAL, Orsay, France T. Tauchi, N. Terunuma KEK, Ibaraki, Japan
	ATF2 is a low energy (1.3GeV) prototype of the final focus system for ILC and CLIC linear collider projects. A major goal of ATF2 is to demonstrate the ability to stabilise the beam position at the interaction point, where the beam can be focused down to about 35 nm. For this purpose, a set of new Beam Position Monitors (BPM) has been designed, with an expected resolution of about 2 nm. These BPMs must be very well aligned with respect to the beam, at the few micron level, to fully exploit their fine resolution. In this paper, the mechanical positioning system which has been developed to enable such a precise alignment is presented. It is based on a set of eight piezo actuators with nanometer range displacement resolution, mounted in a new specially made vacuum chamber. Due to the expected resolution of the piezo actuators, this system also brings a new functionality, the possibility to calibrate the BPMs by mechanically scanning the beam.
	Slides TUOCB203 [2.276 MB]

TUPME024	Re-optimization of the Final Focus System Optics with Vertical Chromatic Correction	1622
	Y. Wang, J. Gao IHEP, Beijing, People's Republic of China P. Bambade LAL, Orsay, France
	Funding: The France China Particle Physics Laboratory (FCPPL) and The National Natural Science Foundation of China (NSFC, Project 11175192) The purpose of the final focus (FF) system of the future linear collider (ILC and CLIC) is to demagnify the beam to the required size at the IP. This can be done in a compact way based on a local chromaticity correction. Two important issues are beam-beam induced radiation effects and the optical correction strategy to mitigate static and dynamic imperfections. For a small enough beam energy spread, we investigate the possibility to get a smaller vertical beam size, at the expense of a larger horizontal beam size, by re-optimising the final focus optics with chromatic correction mainly in the vertical plane. Firstly, we track the beam with MAD-X, with and without chromaticity correction, to estimate the optimum betax and betay values by rematching the linear optics, and cross-check and improve the rematching procedure with MAPCLASS. Then, we study the original design and an alternative simplified optical system, using a set of enlarged betax values, and optimize the sextupoles as a function of betay to minimize the vertical beam size for different assumptions on the energy spread.

TUPWO003	CLIC 3 TeV Beam Size Optimization with Radiation Effects	1877
	O.R. Blanco, P. Bambade LAL, Orsay, France R. Tomás CERN, Geneva, Switzerland
	Horizontal beamsize contribution due to radiation on bending magnets is calculated using theoretical results and recent improvements in mapclass (Mapclass2). In order to verify the code and validity of its approximations, a simple lattice with no geometrical nor chromatic aberrations, one dipole and a final drift has been used to compare Mapclass2 calculations and Placet tracking results. CLIC 3TeV lattice is optimized including the radiation effects. Current results show that correction of chromatic aberrations impose constraints in radiation improvement.

TUPWO017	Simulation on the Breaking of αx Multiknob Orthogonality in the Presence of Gradient and Coupling Errors and Experimental Investigation	1919
	S. Bai, J. Gao IHEP, Beijing, People's Republic of China P. Bambade LAL, Orsay, France G.R. White SLAC, Menlo Park, California, USA
	The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. In beam tuning towards the goal beam size, the presence of a tilt of the IP Shintake monitor fringe pattern with respect to the x-y coordinate system of the beam can break the orthogonality in the main σ34 and σ32 waist corrections required to reduce the vertical beam size at IP. Concerning the method of doing αx scan and measuring the vertical beam size to diagnose the IPBSM fringe tilt or residual σ13, one thing should be studied is to check what could break the orthogonality of the αx knob other than σ13 and the IPBSM fringe tilt. In this paper, we report on the simulation study that check for the breaking of orthogonality of the αx knob in the presence of gradient and coupling errors; to what extent this breaking of orthogonality can go; and also calculate the IPBSM fringe tilt angle from experiment results.