400 MHz rf cavities
D. Angal-Kalinin et al., LHC Project-Report 595, Review of Coupled-Bunch Instabilities in the LHC
E. Haebel et al., CERN-SL-98-008-RF. The Higher-Order Mode Dampers of the 400 MHz Superconducting LHC Cavities [Damped and undamped longitudinal and dipole modes. Only Q values given in table, no R_sh or R/Q]
| number of units | |
| average beta function x, y | m, m |
| Z/n per unit | Ohm |
| longitudinal loss factor | V/pC |
Missing:
Note:
J. Tuckmantel informed us that all monopoles propagate through the large beam tube, hence a module with 4 single cell cavities is for the HOMs a 4-cell supercavity. Due to fabrication tolerances the individual cavity HOM frequencies have a non-negligible scatter. The worst case is that one mode is synchronous over the full module and thus appears equal to 4 times a single cavity with dampers. The R/Q of the fundamental mode is 45 Ohm. If Joachim remembers right, the R/Q of the worst HOM should be about 1/3 of that. ‘Unfortunately the main actors of the LHC cavity design are retired or back to their labs elsewhere.’