IPAC2011 - List of Authors (Vanbavinckhove, G.)

Paper	Title	Page
TUPZ001	90 m Optics Commissioning	1795
	S. Cavalier LAL, Orsay, France H. Burkhardt, M. Fitterer, G.J. Müller, S. Redaelli, R. Tomás, G. Vanbavinckhove, J. Wenninger CERN, Geneva, Switzerland
	Special β* = 90 m optics have been developed for the two very high luminosity insertions of the LHC, as a first step towards to allow for very low angle precision measurements of the proton-proton collisions in the LHC. These optics were developed to be compatible with the standard LHC injection and ramp optics. The target value of β* = 90 m is reached by an un-squeeze from the injection β* = 11 m. We describe the implementation of this optics in the LHC and the first experience in the commissioning of these optics.

WEPC029	Accuracy of the LHC Optics Measurement based on AC Dipoles	2064
	R. Miyamoto, R. Calaga BNL, Upton, Long Island, New York, USA R. Tomás, G. Vanbavinckhove CERN, Geneva, Switzerland
	Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP). The tight tolerances in the LHC requires optics measurement with very good accuracy. Therefore, AC dipoles are employed as the primary devices to measure the LHC optics. The accuracy of the measurement is mainly determined by the length of the coherent signal, signal-to-noise ratio of the measurement, and the data processing to effectively suppress the noise. This paper presents numerical and experimental studies of how these factors affect the accuracy of the LHC optics measurement using the AC dipoles.

WEPC030	Measurement of Coupling Resonance Driving Terms in the LHC with AC Dipoles	2067
	R. Miyamoto, R. Calaga BNL, Upton, Long Island, New York, USA M. Aiba PSI, Villigen, Switzerland R. Tomás, G. Vanbavinckhove CERN, Geneva, Switzerland
	Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP). Transverse betatron coupling in the LHC is measured from Fourier analysis of turn-by-turn beam oscillations excited by AC dipoles. The use of the AC dipole for optics measurements induces a small systematic error which can be corrected with an appropriate data interpretation. An algorithm to apply this correction to the measurement of the coupling resonance driving terms is developed for the first time. This paper will review this new algorithm and present results of its application to the LHC.

WEPC031	Optics Corrections at RHIC	2070
	G. Vanbavinckhove CERN, Geneva, Switzerland M. Bai, G. Robert-Demolaize BNL, Upton, Long Island, New York, USA
	Excessive beta-beat, deviation of measured beta function from the calculated beta functions based on an model, in high energy colliders can lead to large deviation of beta function at collision point as well as other adverse effects. The segment-by-segment technique was successfully demonstrated in the LHC operation for reducing the beta-beat. It was then applied to RHIC polarized proton operation in 2011. This paper reports the experimental results of optics correction at RHIC. Future plan is also presented.

WEPC078	Non-linear Chromaticity Studies of the LHC at Injection	2199
	E.H. Maclean, M. Giovannozzi, F. Schmidt, R.J. Steinhagen, E. Todesco, R. Tomás, G. Vanbavinckhove CERN, Geneva, Switzerland R. Bartolini JAI, Oxford, United Kingdom
	The non-linear chromaticity of the LHC has been studied. Measurements of variation in tune with dp/p on both beams at injection optics are being compared with Q'' and Q''' as calculated with the LHC effective model. This model uses the best currently available measurements of magnetic field harmonics. An attempt is being made to optimize the b4 and b5 pool-pieces corrections in view of the corresponding chromaticity terms.

TUPZ026	Alternative Working Point(s) at Injection for the LHC	1861
	R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands
	Funding: This work partially supported by the US Department of Energy through the LHC Accelerator Research Program (LARP). At present, the LHC operates with a different fractional tunes at injection and at collision energy due to improved dynamic aperture indicated by tracking studies. Therefore, a tune swing crossing the 10th order resonance is needed during the beta-squeeze. A new proposal to alter the working point to collision tunes already at injection and during an energy ramp is foreseen to avoid the tune jump. Simulations and measurements of the optics along with the beam emittances and lifetime are compared to the nominal injection tunes. Feasibility for a working point close to the 1/2 integer is also attempted.

TUPZ027	Beta* Measurement in the LHC Based on K-modulation	1864
	R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands
	Funding: This work partially supported by the US Department of Energy through the LHC Accelerator Research Program (LARP). Accurate knowledge of the collision point optics is crucial to equalize the luminosities at the different experiments. K-modulation was successfully applied at several accelerators for measuring the lattice beta functions. In the LHC, it was proposed as an alternative method to compute the beta* at the collision points. Results of beta* measurements in the LHC based on the K-modulation technique are presented with comparisons to nominal segment-by-segment method.

TUPZ034	Impact of Arc Phase Advance on Chromatic Optics in RHIC	1885
	R. Calaga, R. Miyamoto, G. Robert-Demolaize, S.M. White BNL, Upton, Long Island, New York, USA R. De Maria, R. Tomás CERN, Geneva, Switzerland G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands
	Funding: This work is partially supported by the US Department of Energy through the LHC Accelerator Research program (LARP). The phase advance between the two interaction points in RHIC is optimized for dynamic aperture for a initial design beta-star. This may not hold true as RHIC presently operates with a considerably reduced beta-star. Additionally the reduction of the available beam aperture due to an enlarged chromatic beta-beating is evident. Results from phase advance scans between the two IPs to reduce the chromatic beta-beating in model and measurements are presented. Impact on the single beam lifetime and momentum aperture is compared to the nominal optics.

WEPC004	Comparison of the Action and Phase Analysis on LHC Orbits with Other Techniques	2004
	J.F. Cardona UNAL, Bogota D.C, Colombia R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands
	Funding: DIB-Universidad Nacional de Colombia Recently acquired turn-by-turn data of the LHC is analyzed using the action and phase jump technique. The results of this analysis show a visible variation of the action and phase plots at the interaction regions from which optic error estimations can be done. In this paper error estimations will be presented and comparisons with other existing techniques in the LHC, such as the recently implemented Segment-by-segment technique, will be discussed.

WEPC028	Record Low Beta-beat of 10% in the LHC	2061
	G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands M. Aiba PSI, Villigen, Switzerland R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA R. Tomás CERN, Geneva, Switzerland
	During the 2011 LHC run several measurements and correction campaigns were conducted. As a result a peak beta-beat of 10% level was achieved. This level, well below the specified tolerances of the LHC, improves the aperture margins and helps minimize the luminosity imbalance between the different experiments. A combination of local corrections at the insertion regions and an overall global correction were used to achieve this record low beta-beat. The sequence of the optics corrections and stability along the 2011 run are reported.

WEPC032	First Measurements of Higher Order Optics Parameters in the LHC	2073
	G. Vanbavinckhove NIKHEF, Amsterdam, The Netherlands M. Aiba PSI, Villigen, Switzerland R. Bartolini Diamond, Oxfordshire, United Kingdom R. Calaga, R. Miyamoto BNL, Upton, Long Island, New York, USA M. Giovannozzi, F. Schmidt, R. Tomás CERN, Geneva, Switzerland E.H. Maclean JAI, Oxford, United Kingdom
	Higher order effects can play an important role in the performance of the LHC. Lack of knowledge of these parameters can increase the tune footprint and compromise the beam lifetime. First measurements of these parameters at injection and flattop have been conducted. Detailed simulations are compared to the measurements together with discussions on the measurement limitations.

Paper

Title

Page

90 m Optics Commissioning

1795

S. Cavalier
LAL, Orsay, France
H. Burkhardt, M. Fitterer, G.J. Müller, S. Redaelli, R. Tomás, G. Vanbavinckhove, J. Wenninger
CERN, Geneva, Switzerland

Special β* = 90 m optics have been developed for the two very high luminosity insertions of the LHC, as a first step towards to allow for very low angle precision measurements of the proton-proton collisions in the LHC. These optics were developed to be compatible with the standard LHC injection and ramp optics. The target value of β* = 90 m is reached by an un-squeeze from the injection β* = 11 m. We describe the implementation of this optics in the LHC and the first experience in the commissioning of these optics.

WEPC029

Accuracy of the LHC Optics Measurement based on AC Dipoles

2064

R. Miyamoto, R. Calaga
BNL, Upton, Long Island, New York, USA
R. Tomás, G. Vanbavinckhove
CERN, Geneva, Switzerland

Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
The tight tolerances in the LHC requires optics measurement with very good accuracy. Therefore, AC dipoles are employed as the primary devices to measure the LHC optics. The accuracy of the measurement is mainly determined by the length of the coherent signal, signal-to-noise ratio of the measurement, and the data processing to effectively suppress the noise. This paper presents numerical and experimental studies of how these factors affect the accuracy of the LHC optics measurement using the AC dipoles.

WEPC030

Measurement of Coupling Resonance Driving Terms in the LHC with AC Dipoles

2067

R. Miyamoto, R. Calaga
BNL, Upton, Long Island, New York, USA
M. Aiba
PSI, Villigen, Switzerland
R. Tomás, G. Vanbavinckhove
CERN, Geneva, Switzerland

Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
Transverse betatron coupling in the LHC is measured from Fourier analysis of turn-by-turn beam oscillations excited by AC dipoles. The use of the AC dipole for optics measurements induces a small systematic error which can be corrected with an appropriate data interpretation. An algorithm to apply this correction to the measurement of the coupling resonance driving terms is developed for the first time. This paper will review this new algorithm and present results of its application to the LHC.

WEPC031

Optics Corrections at RHIC

2070

G. Vanbavinckhove
CERN, Geneva, Switzerland
M. Bai, G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA

Excessive beta-beat, deviation of measured beta function from the calculated beta functions based on an model, in high energy colliders can lead to large deviation of beta function at collision point as well as other adverse effects. The segment-by-segment technique was successfully demonstrated in the LHC operation for reducing the beta-beat. It was then applied to RHIC polarized proton operation in 2011. This paper reports the experimental results of optics correction at RHIC. Future plan is also presented.

WEPC078

Non-linear Chromaticity Studies of the LHC at Injection

2199

E.H. Maclean, M. Giovannozzi, F. Schmidt, R.J. Steinhagen, E. Todesco, R. Tomás, G. Vanbavinckhove
CERN, Geneva, Switzerland
R. Bartolini
JAI, Oxford, United Kingdom

The non-linear chromaticity of the LHC has been studied. Measurements of variation in tune with dp/p on both beams at injection optics are being compared with Q'' and Q''' as calculated with the LHC effective model. This model uses the best currently available measurements of magnetic field harmonics. An attempt is being made to optimize the b4 and b5 pool-pieces corrections in view of the corresponding chromaticity terms.

TUPZ026

Alternative Working Point(s) at Injection for the LHC

1861

R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
R. Tomás
CERN, Geneva, Switzerland
G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands

Funding: This work partially supported by the US Department of Energy through the LHC Accelerator Research Program (LARP).
At present, the LHC operates with a different fractional tunes at injection and at collision energy due to improved dynamic aperture indicated by tracking studies. Therefore, a tune swing crossing the 10th order resonance is needed during the beta-squeeze. A new proposal to alter the working point to collision tunes already at injection and during an energy ramp is foreseen to avoid the tune jump. Simulations and measurements of the optics along with the beam emittances and lifetime are compared to the nominal injection tunes. Feasibility for a working point close to the 1/2 integer is also attempted.

TUPZ027

Beta* Measurement in the LHC Based on K-modulation

1864

R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
R. Tomás
CERN, Geneva, Switzerland
G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands

Funding: This work partially supported by the US Department of Energy through the LHC Accelerator Research Program (LARP).
Accurate knowledge of the collision point optics is crucial to equalize the luminosities at the different experiments. K-modulation was successfully applied at several accelerators for measuring the lattice beta functions. In the LHC, it was proposed as an alternative method to compute the beta* at the collision points. Results of beta* measurements in the LHC based on the K-modulation technique are presented with comparisons to nominal segment-by-segment method.

TUPZ034

Impact of Arc Phase Advance on Chromatic Optics in RHIC

1885

R. Calaga, R. Miyamoto, G. Robert-Demolaize, S.M. White
BNL, Upton, Long Island, New York, USA
R. De Maria, R. Tomás
CERN, Geneva, Switzerland
G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands

Funding: This work is partially supported by the US Department of Energy through the LHC Accelerator Research program (LARP).
The phase advance between the two interaction points in RHIC is optimized for dynamic aperture for a initial design beta-star. This may not hold true as RHIC presently operates with a considerably reduced beta-star. Additionally the reduction of the available beam aperture due to an enlarged chromatic beta-beating is evident. Results from phase advance scans between the two IPs to reduce the chromatic beta-beating in model and measurements are presented. Impact on the single beam lifetime and momentum aperture is compared to the nominal optics.

WEPC004

Comparison of the Action and Phase Analysis on LHC Orbits with Other Techniques

2004

J.F. Cardona
UNAL, Bogota D.C, Colombia
R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
R. Tomás
CERN, Geneva, Switzerland
G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands

Funding: DIB-Universidad Nacional de Colombia
Recently acquired turn-by-turn data of the LHC is analyzed using the action and phase jump technique. The results of this analysis show a visible variation of the action and phase plots at the interaction regions from which optic error estimations can be done. In this paper error estimations will be presented and comparisons with other existing techniques in the LHC, such as the recently implemented Segment-by-segment technique, will be discussed.

WEPC028

Record Low Beta-beat of 10% in the LHC

2061

G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands
M. Aiba
PSI, Villigen, Switzerland
R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
R. Tomás
CERN, Geneva, Switzerland

During the 2011 LHC run several measurements and correction campaigns were conducted. As a result a peak beta-beat of 10% level was achieved. This level, well below the specified tolerances of the LHC, improves the aperture margins and helps minimize the luminosity imbalance between the different experiments. A combination of local corrections at the insertion regions and an overall global correction were used to achieve this record low beta-beat. The sequence of the optics corrections and stability along the 2011 run are reported.

WEPC032

First Measurements of Higher Order Optics Parameters in the LHC

2073

G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands
M. Aiba
PSI, Villigen, Switzerland
R. Bartolini
Diamond, Oxfordshire, United Kingdom
R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
M. Giovannozzi, F. Schmidt, R. Tomás
CERN, Geneva, Switzerland
E.H. Maclean
JAI, Oxford, United Kingdom

Higher order effects can play an important role in the performance of the LHC. Lack of knowledge of these parameters can increase the tune footprint and compromise the beam lifetime. First measurements of these parameters at injection and flattop have been conducted. Detailed simulations are compared to the measurements together with discussions on the measurement limitations.