IBIC2012 - List of Keywords (resonance)

Paper	Title	Other Keywords	Page
TUPA32	Signal Equalizer for SPS Ecloud/TMCI Instability Feedback Control System	pick-up, controls, feedback, network	424
	K.M. Pollock, J.E. Dusatko, J.D. Fox, C.H. Rivetta, D. Van Winkle SLAC, Menlo Park, California, USA R. Secondo CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract #DE-AC02-76F00515 and the US LHC Accelerator Research Program. The 4GS/sec electron cloud and transverse mode coupled instability (TMCI) control system in development for the CERN Super Proton Synchrotron (SPS) requires 1.5GHz of processing bandwidth for the beam pickups and signal digitizer. An exponentially tapered stripline pickup has sufficient bandwidth, but has a phase response that distorts the beam signal in the time domain. We report on results from the design and implementation of an equalizer for the front end signal processing with correction for the pickup and cable responses. Using a model of the transfer functions for the pickups and the cabling, we determine a desired frequency response for the equalizer. Design for the circuitry, component value fitting is discussed as well as board construction and reduction of parasitic impedances. Finally, we show results from the measurement of an assembled equalizer, compare them with simulations and show beam signals from use at the SPS.

TUPB49	Electron Cloud Density Measurements using Resonant TE Waves at CesrTA	electron, simulation, storage-ring, positron	471
	J.P. Sikora, M.G. Billing, D.O. Duggins, Y. Li, D. L. Rubin, R.M. Schwartz, K.G. Sonnad CLASSE, 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. The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) with beam energies ranging from 2 GeV to 5 GeV of either positrons or electrons. Research at CesrTA includes the study of the growth, decay and mitigation of electron clouds in the storage ring. Electron Cloud (EC) densities can be measured by resonantly exciting the beam-pipe with microwaves. The EC density will change beam-pipe's resonant frequency by an amount that is proportional to the local electric field squared of the standing waves. When the EC density is not uniform, it is especially important to know the standing wave pattern in order to obtain an absolute EC density measurement. We will present our current understanding of this technique in the context of new test sections of beam-pipe installed in August 2012. This will include bench measurements of standing waves in the beam-pipe, simulations of this geometry and recent EC density measurements with beam.

THTA01	Beam Position Monitors for Circular Accelerators	pick-up, impedance, coupling, closed-orbit	590
	S. Hiramatsu KEK, Ibaraki, Japan
	The electrostatic induction type beam position monitors (BPMs) for circular accelerators such as proton synchrotrons and electron accumulation rings will be discussed. Discussions on the beam induced charge on the BPM pick-up electrodes, signal detection systems, and techniques of beam based alignment and beam based calibration will be given. For high beam current machines, the evaluation of the beam coupling impedance of BPM is an important issue to avoid the beam current limit by beam instabilities caused by BPM impedances. Another serious problem is the movement of BPMs by the thermal distortion of the beam pipe by high power synchrotron radiation. These problems will be also mentioned briefly.
	Slides THTA01 [6.252 MB]

Paper

Title

Other Keywords

Page

TUPA32

Signal Equalizer for SPS Ecloud/TMCI Instability Feedback Control System

pick-up, controls, feedback, network

424

K.M. Pollock, J.E. Dusatko, J.D. Fox, C.H. Rivetta, D. Van Winkle
SLAC, Menlo Park, California, USA
R. Secondo
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract #DE-AC02-76F00515 and the US LHC Accelerator Research Program.
The 4GS/sec electron cloud and transverse mode coupled instability (TMCI) control system in development for the CERN Super Proton Synchrotron (SPS) requires 1.5GHz of processing bandwidth for the beam pickups and signal digitizer. An exponentially tapered stripline pickup has sufficient bandwidth, but has a phase response that distorts the beam signal in the time domain. We report on results from the design and implementation of an equalizer for the front end signal processing with correction for the pickup and cable responses. Using a model of the transfer functions for the pickups and the cabling, we determine a desired frequency response for the equalizer. Design for the circuitry, component value fitting is discussed as well as board construction and reduction of parasitic impedances. Finally, we show results from the measurement of an assembled equalizer, compare them with simulations and show beam signals from use at the SPS.

TUPB49

Electron Cloud Density Measurements using Resonant TE Waves at CesrTA

electron, simulation, storage-ring, positron

471

J.P. Sikora, M.G. Billing, D.O. Duggins, Y. Li, D. L. Rubin, R.M. Schwartz, K.G. Sonnad
CLASSE, 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.
The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) with beam energies ranging from 2 GeV to 5 GeV of either positrons or electrons. Research at CesrTA includes the study of the growth, decay and mitigation of electron clouds in the storage ring. Electron Cloud (EC) densities can be measured by resonantly exciting the beam-pipe with microwaves. The EC density will change beam-pipe's resonant frequency by an amount that is proportional to the local electric field squared of the standing waves. When the EC density is not uniform, it is especially important to know the standing wave pattern in order to obtain an absolute EC density measurement. We will present our current understanding of this technique in the context of new test sections of beam-pipe installed in August 2012. This will include bench measurements of standing waves in the beam-pipe, simulations of this geometry and recent EC density measurements with beam.

THTA01

Beam Position Monitors for Circular Accelerators

pick-up, impedance, coupling, closed-orbit

590

S. Hiramatsu
KEK, Ibaraki, Japan

The electrostatic induction type beam position monitors (BPMs) for circular accelerators such as proton synchrotrons and electron accumulation rings will be discussed. Discussions on the beam induced charge on the BPM pick-up electrodes, signal detection systems, and techniques of beam based alignment and beam based calibration will be given. For high beam current machines, the evaluation of the beam coupling impedance of BPM is an important issue to avoid the beam current limit by beam instabilities caused by BPM impedances. Another serious problem is the movement of BPMs by the thermal distortion of the beam pipe by high power synchrotron radiation. These problems will be also mentioned briefly.

Slides THTA01 [6.252 MB]