RTML and Main Linac Design (2.6.1 and 2.7.1) PT SLAC ILC R&D Meeting Global Design Effort

2006 BC Emittance Preservation Kubo-san did studies using steering and dispersion bumps Predicted rather large emittance dilutions Not reproduced when SLAC team did nominally-identical studies SLAC team got much smaller emittance growths, even for simple case of misaligned quads and BPMs What’s up with this? ILC R&D Meeting Global Design Effort

2006 BC Emittance Preservation (2) Found 2 differences in the studies Kubo-san’s study did not include cavity fringe fields Reduce kick effect of pitched cavities by a factor of 2 Reduces emittance effect of pitched cavities by a factor of 4 Brings his results and ours into agreement for cavities Kubo-san’s study did include misalignments of sector bends in “quads and BPMs only” cases Has a nontrivial effect on emittance Added bend offsets to SLAC study, results reproduced Kubo-san’s Need to go back and do full studies with fully-agreed errors Should migrate to 2007 optics Different configurations of bends, RF stations Longer initial bunch (so worse effects expected) ILC R&D Meeting Global Design Effort

2006 Coupling Correction Cornell group found that putting decoupler near DRX and wire scanners near spin rotator (ie, far away from each other) does not work well Decoupler can zero <xy> but emittance, y dispersion blow up Observed some interplay with x dispersion correction Putting decoupler right next to wire scanners works very well Didn’t understand why Cornellians sent some files to play with ILC R&D Meeting Global Design Effort

2006 Coupling Correction (2) Problem now understood Misaligned skew quads in decoupler, so tuning them introduces y oscillation Oscillation in turnaround  dispersion In presence of x dispersion, adding y dispersion at wire influences <xy> term Complicated parameter space, since tuning skew quads changes betatron coupling and vertical dispersion, and can introduce nonzero <xy> due to x dispersion Raw minimization of <xy> probably not the best “You said zero <xy>, not minimize <yy>” 2007 design has decouplers near wire scanners ILC R&D Meeting Global Design Effort

DRX-RTML Junction Started to look at completing connection between DRX and RTML Requires layout of LTR and DRI as well All need to share a single tunnel Had to drop this temporarily Plan to complete prior to DESY meeting If still incomplete at that time, look for other people to do the work… ILC R&D Meeting Global Design Effort

RTML FY07 to-do list Connect RTML to DRX Tune up RTML geometry Do that myself (hopefully) Tune up RTML geometry Cornell FY08-09 WP Tune up RTML matches (Re)Design extraction lines Interest in this at SLAC RF Parameters Static emittance tuning Best effort KEK + SLAC, maybe some CERN Space charge FNAL and LBL groups looking at this Stray fields Understand relevance of ML / RR experience to RTML Return line Cost estimate Like to do a fresh bottoms-up estimate at some point Don’t know if this is practical for FY07 Note: tasks which are “assigned” are in italics ILC R&D Meeting Global Design Effort

RTML (2.6) FY08-09 WPs prepared and presented to Mike and Gerry Not too heavy on “R & D” as such More concentrated on engineering, esp. magnets and beamlines Packing fractions, etc. Some accelerator design work In particular some LEPP WPs in this area FY08: effort centered at SLAC and LEPP FY09: should perhaps look to add some partners inside or outside of US ILC R&D Meeting Global Design Effort

ML Design Nothing new to report since 28 Feb 2007 Planning to have completed e+ and e- lattices on June timescale Proper lengths Proper RF units Proper aperiodicities for cryo hocus-pocus Proper undulator insertion in e- side Vertical curvature Proper match out of RTML and into BDS ILC R&D Meeting Global Design Effort

ML (2.7) FY08-09 WPs prepared. Plan includes: LRWF studies 2-2.2 SLAC FTEs RTML, ML, S2E sims, code development 1.75-2.75 SLAC FTEs S-band BPM test in CM 0.25-0.5 SLAC FTEs FNAL and LEPP also major participants NB: This represents a major jump in effort from what we are doing today in this area! ILC R&D Meeting Global Design Effort