IBIC2012 - List of Authors (Eddy, N.)

Paper	Title	Page
TUPA16	HOM Choice Study with Test Electronics for use as Beam Position Diagnostics in 3.9 GHz Accelerating Cavities in FLASH	364
	N. Baboi, B. Lorbeer, P. Zhang DESY, Hamburg, Germany N. Eddy, B.J. Fellenz, M. Wendt Fermilab, Batavia, USA
	Funding: Work supported in part by the European Commission within the Framework Programme 7, Grant Agreement 227579 Higher Order Modes (HOM) excited by the beam in the 3.9 GHz accelerating cavities in FLASH can be used for beam position diagnostics, as in a cavity beam position monitor. Previous studies of the modal choices within the complicated spectrum have revealed several options: cavity modes with high coupling to the beam, and therefore with the potential for better position resolution, but which are propagating within all 4 cavities, and modes localized in the cavities or the beam pipes, which can give localized position information, but which provide worse resolution. For a better characterization of these options, test electronics has been built, which can down convert various frequencies between about 4 and 9 GHz to 70 MHz. The performance of various 20 MHz bands has been estimated. The best resolution of 20 μm was found for some propagating modes. Based on this study one band at ca. 5 GHz was chosen for high resolution position monitoring and a band at ca. 9 GHz for localized monitoring. N. Baboi et al., SRF2011, Chicago, IL, US

Paper

Title

Page

HOM Choice Study with Test Electronics for use as Beam Position Diagnostics in 3.9 GHz Accelerating Cavities in FLASH

364

N. Baboi, B. Lorbeer, P. Zhang
DESY, Hamburg, Germany
N. Eddy, B.J. Fellenz, M. Wendt
Fermilab, Batavia, USA

Funding: Work supported in part by the European Commission within the Framework Programme 7, Grant Agreement 227579
Higher Order Modes (HOM) excited by the beam in the 3.9 GHz accelerating cavities in FLASH can be used for beam position diagnostics, as in a cavity beam position monitor. Previous studies of the modal choices within the complicated spectrum have revealed several options*: cavity modes with high coupling to the beam, and therefore with the potential for better position resolution, but which are propagating within all 4 cavities, and modes localized in the cavities or the beam pipes, which can give localized position information, but which provide worse resolution. For a better characterization of these options, test electronics has been built, which can down convert various frequencies between about 4 and 9 GHz to 70 MHz. The performance of various 20 MHz bands has been estimated. The best resolution of 20 μm was found for some propagating modes. Based on this study one band at ca. 5 GHz was chosen for high resolution position monitoring and a band at ca. 9 GHz for localized monitoring.
* N. Baboi et al., SRF2011, Chicago, IL, US