Update on ILC ML Lattice Design Alexander Valishev, for the FNAL LET group FNAL AP Dept. Meeting March 7, 2007

APD meeting March 7, 07 ML Lattice design 2 Outline Basic layout Curvature implementation Matching Summary and problems

APD meeting March 7, 07 ML Lattice design 3 Lattice Design Defined by cryo segmentation Versions of segmentation »8-8-8 scheme, May »9-8-9 scheme, Dec Basic segmentations: Main Linac RF Unit Cryogenic Unit

APD meeting March 7, 07 ML Lattice design May 31 revision (v.3) 8-8-8

APD meeting March 7, 07 ML Lattice design 5 Curvature Implementation Beam line geometry definition differs for MatLIAR/Lucretia and MAD. A method to have one set of decks and still be able to work with two codes was proposed by M.Woodley: »One common XSIF file, defining beam line, all common elements, and KINK elements at the ends of cryomodules. »Two different files defining KINK elements to be used in MatLIAR and MAD. One of the files is called from the main file depending on the software used. »Beam trajectory in both cases is changed by VKICK elements Another approach is to use vertical SBENDs »In this case one deck is compatible with both codes

APD meeting March 7, 07 ML Lattice design 6 Curvature Implementation GKICK, Multipole SBEND

APD meeting March 7, 07 ML Lattice design 7 Implementation of KINKs MatLIAR/Lucretia: Thin dispersion-free kick GKICK, which pitches the coordinate system. MAD: Combination of »General thin multipole n=0, changes both the beam trajectory and the coordinate system »VKICK of the opposite sign

APD meeting March 7, 07 ML Lattice design 8 ILC2006e (8-8-8) Lattice -functions

APD meeting March 7, 07 ML Lattice design 9 ILC2006e Orbit

APD meeting March 7, 07 ML Lattice design 10 ILC2006e Dispersion

APD meeting March 7, 07 ML Lattice design 11 Emittance Preservation LIAR Simulation: CURVED LINAC: ILC BCD-Like LATTICE Orbit at the YCORs ( m) Perfect Lattice - No misalignments Zoom Normalized Emittance (nm) Static Tuning: Dispersion Matched Steering (DMS) - Misalign the beamline components and perform the steering Average of 50 machines Straight Curved Corrected normalized emittance (nm) Mean: 5.0 ± 0.4 nm 90%: 8.7 nm Laser Straight Mean: 5.3 ± 0.5 nm 90%: 9.5 nm Curved Distribution of emittance growth for 50 seeds BPM index

APD meeting March 7, 07 ML Lattice design 12 Summary ML lattices based on two cryogenic layouts have been developed Two versions of ILC2006e (8-8-8) ML lattice (GKICK/MULT and SBEND) were studied »Both versions work well in Lucretia and show similar emittance growth »It was decided at the Daresbury meeting in January that only GKICK/MULT lattice will be supported Static alignment simulations show acceptable emittance growth in the curved ML lattice Dynamic simulations in progress

APD meeting March 7, 07 ML Lattice design 13 Problems Create set of decks suitable for simulations of bunch propagation from RTML to the end Improve dispersion matching between curved and straight sections »The way it was implemented in ILC2006e suggests large orbit kinks with angles of ~3e-4 »At 250 GeV, this leads to energy losses of 100MeV and synchrotron radiation power of 4kW »One possible solution – make smooth transition from curved to straight beam line.