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coherent tune shift due to collimator impedance - its dependence on gap size - work in progress. impedance of single flat collimator. s C =10 5 W -1 m -1. s Cu =5.9x10 7 W -1 m -1. b =70 m b =6 s d =3 cm 7 TeV B-L theory. C. Cu. C. Cu. Gaussian weight functions. Q’=0. Q’=10.
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coherent tune shift due to collimator impedance - its dependence on gap size-work in progress Frank Zimmermann, RLC, 05.05.2006
impedance of single flat collimator sC=105W-1m-1 sCu=5.9x107W-1m-1 b=70 m b=6 s d=3 cm 7 TeV B-L theory C Cu C Cu Frank Zimmermann, RLC, 05.05.2006
Gaussian weight functions Q’=0 Q’=10 m=0 Q’=10 m=1 Frank Zimmermann, RLC, 05.05.2006
coherent coupled-bunch head-tail tune shifts Frank Zimmermann, RLC, 05.05.2006
maximum growth rate ImDQ vs. gap for m=0, Q’=0 units to be confirmed (should have been 1/s, but b was missing) carbon computed growth rates fit result fitted curve where x is the gap size nearly inversely linear dependence on gap size!? Frank Zimmermann, RLC, 05.05.2006
next steps: • sort out coefficients in notebook • plot total tune shifts • study parameter dependencies Frank Zimmermann, RLC, 05.05.2006