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CLIC e+ damping ring. layout. performance with 0.5% coupling & wiggler period l w =10 cm. equilibrium emittances. V rf =3.03 MV. V rf =2.55 MV. beam-based tuning & tolerances being studied. M. Korostelev, CERN & U Lausanne. why is CLIC emittance smaller than NLC value?.
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CLIC e+ damping ring layout performance with 0.5% coupling & wiggler period lw=10 cm equilibrium emittances Vrf=3.03 MV Vrf=2.55 MV beam-based tuning & tolerances being studied M. Korostelev, CERN & U Lausanne
why is CLIC emittance smaller than NLC value? *smaller emittance due to smaller bend angle / arc cell, less emittance detuning, more damping, smaller Hx in wiggler *higher energy reduces intrabeam-scattering effect
e- cloud in CLIC e+ damping ring R. Wanzenberg D. Schulte F. Zimmermann ECLOUD’04 problem at B factories & concern for all LCs: photoelectrons and secondary electrons e- build up in arc dipole 1010 m-1 incident photons CLIC study profits from LHC efforts and SPS/PS experiments 10m-1 photons per meter per e+ with antechamber 1 m-1 assuming 0.06e-/m/e+ pessimistic; insensitive to dmax (1) antechamber not efficient in wiggler (2) e- build up in arcs can reach 1010 m-1, less with antechamber, independent of dmax (3) e- build up in wiggler ~5x109 m-1, depends on dmax (4) beam is stable for line densities of a few 109 m-1 (5) usual remedies work ~4 /m/e+ in wiggler ~0 /m/e+ in arcs note: l=1010 m-1 ~ r=8x1012 m-3 (simulated by ECLOUD code) (simulated by PHOTON code) e- cloud instability e- build up in wiggler 2x1010 m-1 20 kicks/turn preliminary! assuming 0.11e-/m/e+ sensitive to dmax l=2x1010 m-1 ~ r=3.5x1013 m-3 (simulated by ECLOUD code) further studies in EUROTeV (simulated by HEADTAIL code)