# Parameters

Comment:
Some ability to vary the energy is desirable, to trade off instabilities against damping rates and emittances; and to avoid spin depolarisation resonances, if necessary.


Comment:
= Beam energy [eV] / speed of light [m/s]


Comment:
Harmonic number 14042 provides range of options for fill patterns satisfying the timing constraints.  See Reference [1].


Comment:
Frequency fixed at half main linac frequency, for reasons including simplification of synchronisation: see reference [4].


Comment:
Dipole length specified in MAD deck [6].


Comment:
CO equivalent.  After 100 Ahrs beam conditioning.


Parameter:
Electron damping ring vacuum pressure - arc

Comment:
CO equivalent.  After 100 Ahrs beam conditioning.  Upper limit set by fast ion instability [7].


Parameter:
Electron damping ring vacuum pressure - wiggler


Parameter:
Electron damping ring vacuum pressure - straights


Comment:
Specified aperture horizontal x vertical.  Assumed elliptical (or circular) cross-section.


Comment:
Specified aperture horizontal x vertical.


Comment:
Specified aperture horizontal x vertical.  Assumed elliptical cross-section.


Parameter:
Vacuum chamber material - arcs and straights


Comment:
To be determined from mechanical stability considerations.


Comment:
TiZrV provides low outgassing rates, and pumping.  Also provides low SEY in positron ring to suppress electron cloud.  TiN coating an alternative to suppress electron cloud in the positron damping ring.


# References

Reference:
G.Penn "Timing Issues for the ILC Damping Rings" (May 2007)#https://wiki.lepp.cornell.edu/ilc/pub/Public/DampingRings/DampingRingReports/ilc_timing.pdf#


Reference:
A.Wolski et al "Recommendations for ILC Configurations Satisfying Timing Constraints" (April 2006)#https://wiki.lepp.cornell.edu/ilc/pub/Public/DampingRings/WebHome/TimingRecommendations-RevApril7.pdf#


Reference:
Change Control Board, Configuration Change Request No.3 (Feb 2006)#http://www.linearcollider.org/wiki/lib/exe/fetch.php?id=bcd%3Abcd_history&cache=cache&media=bcd:ccb-com-dr20060227.pdf#


Reference:
J. Urban et al "Optimization of CESR-c Superferric Wiggler for the ILC Damping Rings" EPAC06#http://accelconf.web.cern.ch/AccelConf/e06/PAPERS/MOPLS142.PDF#


Reference:
L.Wang et al "Ion Effects in the Electron Damping Ring of the ILC" EPAC06#http://epaper.kek.jp/e06/PAPERS/WEPCH103.PDF#


