IPAC2011 - List of Authors (Teytelman, D.)

Paper	Title	Page
MOPO006	DAΦNE Bunch-by-bunch Feedback Upgrade as SuperB Design Test	490
	A. Drago INFN/LNF, Frascati (Roma), Italy D. Teytelman Dimtel, San Jose, USA
	DAΦNE, the PHI-factory located in Frascati, has always shown dynamic behavior strongly dependent on the bunch-by-bunch feedback, since its first runs in 1997. Over the years, to keep up with the evolving machine requirements, transverse and longitudinal systems have received multiple upgrades and updates. During fall 2010, all the six DAΦNE feedback systems have been upgraded to support the next run for KLOE as well as to test bunch-by-bunch feedback architectures intended for the future Italian SuperB factory. Both e+/e^- longitudinal feedback systems have been completely replaced with new hardware for increased reliability, better diagnostics and improved maintainability. In the effort to reduce residual dipole beam motion, determined by the front-end and quantization noise floor, vertical feedback systems now feature a 12-bit ADC, in place of the older 8-bit design. In the paper, we describe the hardware and software changes of this upgrade. Feedback performance analysis and beam dynamics data collected by the systems are presented.

MOPS090	Observation of Beam Ion Instability in SPEAR3	814
	L. Wang, Y. Cai, W.J. Corbett, T.O. Raubenheimer, J.A. Safranek, J.F. Schmerge, J.J. Sebek SLAC, Menlo Park, California, USA D. Teytelman Dimtel, San Jose, USA
	Weak vertical coupled bunch instability with oscillation amplitude at μm level has been observed in SPEAR3. The instability becomes stronger when there is a vacuum pressure rise by partially turning off vacuum pumps and it becomes weaker when the vertical beam emittance is increased by turning off the skew quadrupole magnets. These confirmed that the instability was driven by ions in the vacuum. The threshold of the beam ion instability when running with a single bunch train is just under 200 mA. This paper presents the comprehensive observations of the beam ion instability in SPEAR3. The effects of vacuum pressure, beam current, beam filling pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail.pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail.

Paper

Title

Page

DAΦNE Bunch-by-bunch Feedback Upgrade as SuperB Design Test

490

A. Drago
INFN/LNF, Frascati (Roma), Italy
D. Teytelman
Dimtel, San Jose, USA

DAΦNE, the PHI-factory located in Frascati, has always shown dynamic behavior strongly dependent on the bunch-by-bunch feedback, since its first runs in 1997. Over the years, to keep up with the evolving machine requirements, transverse and longitudinal systems have received multiple upgrades and updates. During fall 2010, all the six DAΦNE feedback systems have been upgraded to support the next run for KLOE as well as to test bunch-by-bunch feedback architectures intended for the future Italian SuperB factory. Both e+/e^- longitudinal feedback systems have been completely replaced with new hardware for increased reliability, better diagnostics and improved maintainability. In the effort to reduce residual dipole beam motion, determined by the front-end and quantization noise floor, vertical feedback systems now feature a 12-bit ADC, in place of the older 8-bit design. In the paper, we describe the hardware and software changes of this upgrade. Feedback performance analysis and beam dynamics data collected by the systems are presented.

MOPS090

Observation of Beam Ion Instability in SPEAR3

814

L. Wang, Y. Cai, W.J. Corbett, T.O. Raubenheimer, J.A. Safranek, J.F. Schmerge, J.J. Sebek
SLAC, Menlo Park, California, USA
D. Teytelman
Dimtel, San Jose, USA

Weak vertical coupled bunch instability with oscillation amplitude at μm level has been observed in SPEAR3. The instability becomes stronger when there is a vacuum pressure rise by partially turning off vacuum pumps and it becomes weaker when the vertical beam emittance is increased by turning off the skew quadrupole magnets. These confirmed that the instability was driven by ions in the vacuum. The threshold of the beam ion instability when running with a single bunch train is just under 200 mA. This paper presents the comprehensive observations of the beam ion instability in SPEAR3. The effects of vacuum pressure, beam current, beam filling pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail.pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail.