Continued discussions with Alessandra Lombardi as new LCF380 study leader at CERN

Transition into organisation structure for LCF380 study is in preparation

TF Machine design, BDS, beam dynamics, global performance, S2E simulations

• Setup lattice repository, incl. latest ILC & CLIC lattices for reference

  • ILC lattice: Angeles is collecting data, K. Kubo is expert at KEK. Latest international ILC lattice: https://bitbucket.org/whitegr/ilc-lattices/src/master/ 

  • CLIC lattice is available at CERN:  https://gitlab.cern.ch/clic-simulations

  • Andrea makes united repository (CERN gitlab) with ILC TDR, ILC latest, CLIC latest, LCF
    
    

• Re-assess (horizontal) emittance budget:

  • Natural emittance of DR => Yannis looks into first estimate based on https://bitbucket.org/whitegr/ilc-lattices/src/master 

  • Emittance transport RTML, ML, BDS

• Main linac x-ing angle:

  • Define constraints / boundary conditions from beam optics

  • Match with siting constraints (with TF CFS)

  • Fix value
    
    

• 2-BDS design and L*:

  • Does CLIC-like approach work for ILC-like beam parameters?

  • Conceptual design of switch yard

  • Longitudinal displacement required / possible? => LCVision document

  • Decide L* for the 2 IPs [detectors fine with ~4m (ILC-like) L*, larger no problem, i.e. can be any value between CLIC and ILC L* :) ]
    
    

• IP cavern (with TF CFS):

  • 1 or 2 caverns?

  • Longitudinal and transverse separation of IPs: minimum needed for 2 caverns / maximum possible for 1 cavern?
    => LCVision (Terunuma-san, page 78 of arXiv:2503.19983): 30m for transverse only, see also the two slide decks from Angeles & Rogelio linked under “discussion"

  • what would be the impact (eg on luminosity, on BDS length etc) to achieve 30m transverse separation, with 0 longitudinal separation?
    
    

• Extraction line incl dump locations

  • can this be re-used (with slight modifications?)? 

  • Where to locate dumps for 2 BDS, need “3D approach” (with TF CFS)

  • Downstream instrumentation

  • Photon dump location for undulator source? 
    
    

• Design spin rotators for train-by-train adjustment of spin angle at 5 GeV such that Pz = max at either of the two IPs, for all final beam energies  

  • Gudi checks whether ILC spin rotators can achieve arbitrary angle, interested to supervise master student on improved design
    
    

• Luminosity / polarisation risk assessment: S2E simulations, including tolerances, misalignments etc pp
  
  

• Z pole:
  • K. Yokoya: Z pole operation for 380GeV machine: gradient becomes very low if full ML is used (6 MeV), needs some thought (bypass line? => tunnel cross-section)
  • question JL: worthwhile to revisit deceleration concept for e+ source at Z pole?

    Z pole:

  • Part of staging concept?