Placet based DFS simulations in the ILC Main Linac. Some preliminary results of error scans open for discussion Javier Resta Lopez JAI, Oxford University Thanks to Andrea Latina and Daniel Schulte

Placet based Main Linac DFS simulation. Example 1 to 1 correction & dispersion free steering (DFS) Simulation example (100 random seeds averaged) for the ILC: Undulator position Undulator alignment being studied by Duncan Scott et al. (Daresbury). In this simulation we have replaced the undulator by a matching transport matrix !

Vertical emittance distribution Simulation for 100 machines Applying 1to1 and DFS with 1 microm BPM resolution Applying nominal vertical errors: Considering initial vertical norm. emittance (exit from DR and RTML) = 24 nm Dynamics effects: applying GM model C (0.2 s) Distribution at the exit of the Linac Quad offset (μm)300 Quad roll (μrad)300 Cavity offset (μm)300 Cavity pitch (μrad)300 BPM resolution (μm)1 BPM offset (μm)200 About an average 20 % emittance growth

Revisited sensitivity to misalignment errors in the Main Linac Preliminary simulations. Warning: –Straight linac –Cryomodule offset and pitch errors not yet considered here. –Horizontal errors not yet considered here Planning: –Running jobs for linac following the Earth’s curvature –Including horizontal errors. Possible x-y coupling –Scan also to be done for the quad strength error –Suggestions?

Error impact. Some preliminary results Emittance growth vs BPM resolution & BPM offset Average over 100 random seeds. Error bars indicate the statistical standard error: Std dev/ √100

Some preliminary results Emittance growth versus cavity errors Average over 100 random seeds. Error bars indicate the statistical standard error: Std dev/ √100

Some preliminary results Emittance growth versus cavity errors Average over 100 random seeds. In this case the error bars indicate the standard deviation