HOM Choice Study with Test Electronics for use as Beam Position Diagnostics in 3.9 GHz Accelerating Cavities in FLASH
- DESY
- Manchester U.
- Fermilab
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 strong 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, a set of 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 \mu m 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.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1419032
- Report Number(s):
- arXiv:1210.3834; TUPA16; FERMILAB-CONF-12-860-AD; 1190744
- Resource Relation:
- Conference: 1st International Beam Instrumentation Conference, Tsukuba, Japan, 10/01-10/04/2012
- Country of Publication:
- United States
- Language:
- English
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