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| PST04 |
TE Wave Measurements at CesrTA
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resonance, electron, wiggler, positron |
95 |
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- J. Sikora
Cornell University - CLASSE
- S. De Santis
LBNL
- K. Hammond
Harvard University
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Funding: This work is supported by the US National Science Foundation PHY-0734867, and the US Department of Energy DE-FC02-08ER41538
TE Wave measurement systems have been installed in the L0 and L3 regions of CesrTA. L0 is the location of 6 superconducting wiggler magnets; L3 has round beampipe through a chicane magnet (PEPII) and a NEG coated chamber. At both locations, rf relays are used to multiplex signals from a signal generator output, through the beampipe, and to the input of a spectrum analyzer. Software monitors can be triggered to take data on demand, or on changes in accelerator conditions such as beam current or wiggler fields. The poster will describe the TE Wave measurement technique, the installation of hardware at CesrTA and some measurement examples. It will also outline some of the problems in the interpretation of data, specifically the results of reflections and standing waves.
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| PST06 |
Effects of Reflections on TE-Wave Measurements of Electron Cloud Density
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simulation, electron, controls, background |
103 |
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- K. Sonnad, J. Sikora
Cornell University - CLASSE
- K. Hammond
Harvard University
- S. Veitzer
Tech-X Corporation
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The simulation code VORPAL has been used as a tool to study charecteristics of TE wave transmission in the presence of electron clouds for CesrTA. We look at how the electron cloud induced phase shift is influenced by (1) reflections of the wave, caused by possible protrusions in the beam pipe and (2)effect of nonuniformities of the cloud density distribution in the transverse plane.
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| MOD04 |
Modeling Electron Cloud Buildup and Microwave Diagnostics using VORPAL
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electron, simulation, diagnostics, higher-order-mode |
162 |
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- S. Veitzer, P. Stoltz
Tech-X Corporation
- K. Sonnad
Cornell University - CLASSE
- P. Lebrun
Fermilab
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We present an overview of recent electron cloud modeling results using the multi-dimensional, parallel, plasma simulation code VORPAL. We have used VORPAL to model cloud buildup in dipole, quadrupole, and field-free magnetic field configurations, in both circular and elliptical cross section pipes relevant to microwave diagnostics at the PEP-II experiment at SLAC, and ongoing experiments in the Main Injector at Fermilab. In addition, we present preliminary results for modeling electron orbits in the CesrTA wiggler, which is the beginning of a more detailed modeling effort to understand electron cloud effects in electron/positron accelerators, as well as connecting microwave side-band measurements to cloud densities. We also report on recent 3-Dimensional microwave transmission simulations through uniform and non-uniform clouds, and with higher order TE and TM waves using VORPAL.
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Slides
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| DIA00 |
Electron Cloud Studies in the Fermilab Main Injector Using Microwave Transmission
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electron, proton, lattice, dipole |
173 |
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- J. Thangaraj, N. Eddy, R. Zwaska, K. Seiya, I. Kourbanis, J. Crisp
Fermilab
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In this paper, we present recent results from our measurement at the Fermilab Main Injector through microwave transmission in a beam pipe. We present three types of measurement techniques. In the first technique, we use time-resolved direct phase shift measurement to measure the e-cloud density. In the second and third techniques, we look for side bands in the frequency spectrum with or without frequency span by collecting turns of data. Finally, we also discuss the resonant BPM method, where a signal below the waveguide cutoff is sent through a one side of the BPM and is collected on the other side of the BPM to look for phase shift due to electron cloud. We present experimental results taken from MI40 and MI52 section of the main injector.
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Slides
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