| Paper |
Title |
Page |
| TUPCH018 |
Fast Beam Dynamics Investigation Based on an ADC Filling Pattern Measurement
|
1034 |
| |
- J. Kettler, P. Hartmann, R.G. Heine, T. Weis
DELTA, Dortmund
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A diagnostic tool to determine the longitudinal particle filling pattern has been installed at the 1.5 GeV electron storage ring DELTA. The instrument is PC-based using an ADC-conversion at a sampling rate of 2 GS/s and a nominal bandwidth of 1 GHz which is applied to the sumsignal of a single storage ring beam position monitor. By sampling over successive turns the resolution is enhanced by one order of magnitude allowing an easy access to the longitudinal particle distribution inside the ring. The data obtained turn-by-turn over hundreds of revolutions can be further analysed by FFT-techniques allowing a very fast detection (~ 1 s) of longitudinal coupled bunch mode (CBM) instabilities from the phase modulated spectrum. The application of the FFT to the amplitude modulated particle distribution moreover allows a "post mortem"-investigation of CBM induced beam loss. The paper will present the layout of the diagnostic system and will report on filling pattern measurements as well as on investigations of longitudinal CBM-instabilities.
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| THPCH035 |
Characterisation of the EU-HOM-damped Normal Conducting 500 MHz Cavity from the Beam Power Spectrum at DELTA
|
2856 |
| |
- R.G. Heine, P. Hartmann, T. Weis
DELTA, Dortmund
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| |
A HOM-damped prototype cavity developed in the framework of an EC collaboration has been installed into the Dortmund synchrotron light source DELTA. This paper reports on beam studies performed at beam energies of 1.5 GeV and 542 MeV in an attempt to get information on coupled bunch instability thresholds. In addition an evaluation of the longitudinal cavity impedance is presented, based on beam power spectra up to 3 GHz for different filling patterns of the storage ring by analysing the RF signal from the HOM-dampers.
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