IBIC2014 - List of Keywords (resonance)

Paper	Title	Other Keywords	Page
WEPF06	A New Integrating Current Transformer for the LHC	instrumentation, proton, operation, luminosity	540
	L. Søby, D. Belohrad, M. Krupa, P. Odier CERN, Geneva, Switzerland J.F. Bergoz, F. Stulle BERGOZ Instrumentation, Saint Genis Pouilly, France
	The existing fast beam current transformers of the LHC have been shown to exhibit both bunch length and bunch position dependency. A new Integrating Current Transformer (ICT) have therefore been developed in collaboration with Bergoz Instrumentation to address these issues. As goals a 0.1 %/mm beam position dependency and 0.1 % bunch length dependency were specified, along with a bandwidth of 100 MHz. This paper describes the principles of ICT operation and presents the laboratory measurement results obtained with the first prototypes at CERN.
	Poster WEPF06 [2.286 MB]
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WEPF21	Electron Cloud Density Measurements Using Resonant Microwaves at CesrTA	electron, positron, storage-ring, photon	592
	J.P. Sikora Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA S. De Santis LBNL, Berkeley, California, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505. Hardware has recently been installed in the Cornell Electron Storage Ring (CESR) to extend the capability of resonant microwave measurement of electron cloud density. Two new detector locations include aluminum beam-pipe in a dipole magnet and copper beam-pipe in a field free region. Measurements with both positron and electron beams are presented with both beams showing saturation of the electron cloud density in the aluminum chamber. These measurements were made at CESR which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV.
	Poster WEPF21 [1.988 MB]
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WEPF25	A Fast Quadrupole Magnet for Machine Studies at Diamond	quadrupole, simulation, photon, storage-ring	605
	A.F.D. Morgan, G. Rehm DLS, Oxfordshire, United Kingdom
	Fast quadrupolar magnets have been demonstrated in various schemes for increasing the coupled bunch instability thresholds, and for measuring the shift of transverse quadrupolar moment oscillation thus probing the transverse quadrupolar impedance. Due to machine upgrades, a ceramic vessel installed in the Diamond storage ring has become temporarily available for use. We decided to take advantage of this situation by designing and installing a simple air core quadrupole magnet which can operate at the fundamental quadrupolar frequencies (~212kHz for the horizontal and ~405kHz for the vertical plane). In the first instance we aim to use it to study the coupled bunch instability thresholds and quadrupolar tune shifts.
	Poster WEPF25 [1.359 MB]
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THCXB1	Cross-Calibration of Three Electron Cloud Density Detectors at CesrTA	electron, simulation, detector, photon	722
	J.P. Sikora, J.R. Calvey, J.A. Crittenden Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505. Measurements of electron cloud density using three detector types are compared under the same beam conditions at the same location in the Cornell Electron Storage Ring (CESR). Two of the detectors sample the flux of cloud electrons incident on the beam-pipe wall. The Retarding Field Analyzer (RFA) records the time-averaged charge flux and has a retarding grid that can be biased to select high energy electrons. The Shielded Button Electrode (SBE) samples the electron flux without a retarding grid, acquiring signals with sub-nanosecond resolution. The third detector uses resonant microwaves and measures the electron cloud density within the beam-pipe through the cloud-induced shift in resonant frequency. The analysis will include comparison of the output from POSINST and ECLOUD simulations of electron cloud buildup. These time-sliced particle-in-cell 2D modeling codes – simulating photoelectron production, secondary emission and cloud dynamics – have been expanded to include the electron acceptance of the RFA and SBE detectors in order to model the measured signals. The measurements were made at the CESR storage ring, which has been reconfigured as a test accelerator (CesrTA) providing electron or positron beams ranging in energy from 2 GeV to 5 GeV.
	Slides THCXB1 [3.240 MB]
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Paper

Title

Other Keywords

Page

WEPF06

A New Integrating Current Transformer for the LHC

instrumentation, proton, operation, luminosity

540

L. Søby, D. Belohrad, M. Krupa, P. Odier
CERN, Geneva, Switzerland
J.F. Bergoz, F. Stulle
BERGOZ Instrumentation, Saint Genis Pouilly, France

The existing fast beam current transformers of the LHC have been shown to exhibit both bunch length and bunch position dependency. A new Integrating Current Transformer (ICT) have therefore been developed in collaboration with Bergoz Instrumentation to address these issues. As goals a 0.1 %/mm beam position dependency and 0.1 % bunch length dependency were specified, along with a bandwidth of 100 MHz. This paper describes the principles of ICT operation and presents the laboratory measurement results obtained with the first prototypes at CERN.

Poster WEPF06 [2.286 MB]

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WEPF21

Electron Cloud Density Measurements Using Resonant Microwaves at CesrTA

electron, positron, storage-ring, photon

592

J.P. Sikora
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
S. De Santis
LBNL, Berkeley, California, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
Hardware has recently been installed in the Cornell Electron Storage Ring (CESR) to extend the capability of resonant microwave measurement of electron cloud density. Two new detector locations include aluminum beam-pipe in a dipole magnet and copper beam-pipe in a field free region. Measurements with both positron and electron beams are presented with both beams showing saturation of the electron cloud density in the aluminum chamber. These measurements were made at CESR which has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV.

Poster WEPF21 [1.988 MB]

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WEPF25

A Fast Quadrupole Magnet for Machine Studies at Diamond

quadrupole, simulation, photon, storage-ring

605

A.F.D. Morgan, G. Rehm
DLS, Oxfordshire, United Kingdom

Fast quadrupolar magnets have been demonstrated in various schemes for increasing the coupled bunch instability thresholds, and for measuring the shift of transverse quadrupolar moment oscillation thus probing the transverse quadrupolar impedance. Due to machine upgrades, a ceramic vessel installed in the Diamond storage ring has become temporarily available for use. We decided to take advantage of this situation by designing and installing a simple air core quadrupole magnet which can operate at the fundamental quadrupolar frequencies (~212kHz for the horizontal and ~405kHz for the vertical plane). In the first instance we aim to use it to study the coupled bunch instability thresholds and quadrupolar tune shifts.

Poster WEPF25 [1.359 MB]

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THCXB1

Cross-Calibration of Three Electron Cloud Density Detectors at CesrTA

electron, simulation, detector, photon

722

J.P. Sikora, J.R. Calvey, J.A. Crittenden
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
Measurements of electron cloud density using three detector types are compared under the same beam conditions at the same location in the Cornell Electron Storage Ring (CESR). Two of the detectors sample the flux of cloud electrons incident on the beam-pipe wall. The Retarding Field Analyzer (RFA) records the time-averaged charge flux and has a retarding grid that can be biased to select high energy electrons. The Shielded Button Electrode (SBE) samples the electron flux without a retarding grid, acquiring signals with sub-nanosecond resolution. The third detector uses resonant microwaves and measures the electron cloud density within the beam-pipe through the cloud-induced shift in resonant frequency. The analysis will include comparison of the output from POSINST and ECLOUD simulations of electron cloud buildup. These time-sliced particle-in-cell 2D modeling codes – simulating photoelectron production, secondary emission and cloud dynamics – have been expanded to include the electron acceptance of the RFA and SBE detectors in order to model the measured signals. The measurements were made at the CESR storage ring, which has been reconfigured as a test accelerator (CesrTA) providing electron or positron beams ranging in energy from 2 GeV to 5 GeV.

Slides THCXB1 [3.240 MB]

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reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)