Accelerator Group for LHeC LHeC Meeting at CERN; October Questions raised by Max  does the e-ring fit into the tunnel?  can one bypass ATLAS and CMS?  which interaction region is available?  where can we inject the e-beam?  can one perform simultaneously e-p and p-p collisions?  can one think about at linac-ring solution? Phase 2: -did not have enough time to look in detail into all the above questions  added more questions for work outline

Accelerator Group for LHeC LHeC meeting at CERN; October Can the electron ring be build in the LHC tunnel?  how much synchrotron radiation can be accepted in the tunnel?  SC magnets; orbit corrector magnets and BI electronics!  this will determine the maximum e-beam energy and RF voltage for a ring-ring solution.  which interaction region is available?  definitely NOT IR3 and IR7 (radiation issues) and IR6 (beam dump area and damage potential for experiment) and IR1 and IR5 (ATLAS and CMS experiments)  probably not IR4 (very full [proton RF and beam instrumentation])  only IR2 (ALICE) and IR8 (LHCb) are (in my opinion) potential locations (do not know how ALICE and LHCb react to this!)

Accelerator Group for LHeC LHeC Meeting at CERN; October Installation requirements:  space requirements for the RF (installed only in one IR)?  NC RF: limited to 30 GeV e-beam energy? (LEP1 / 4)  SC RF: requires additional cryogenics!  required space for the klystrons and wave guides  one needs to fix the e-beam energy to answer the above  space requirements for magnet power converter?  all underground alcoves are fully used by LHC equipment.  requires additional new underground alcoves!  space requirement for the electron triplet  might have to move backwards the p-triplet (  * ?)  electron beam emittances? (required e-beam  * ?)

Accelerator Group for LHeC LHeC Meeting at CERN; October where can one inject the electron beam?  old TI12 and TI18 lines near IR1 (ATLAS):  are the injection lines compatible with the experiments and insertion magnets of the LHC proton ring?  what happens incase of injection failures (proton beam protection)?  new transfer lines:  requires substantial new tunneling (a couple of km!)  probably similar tunneling work as for a ring-linac option!

Accelerator Group for LHeC LHeC Meeting at CERN; October can one perform simultaneously e-p and p-p collisions?  requires by-passing the other experiments:  additional tunneling and total tunnel length for e-beam  e-beam tunnel circumference must fit to the proton ring circumference!  store length of p-p (10h to 14h) and e-p (5h) and refilling schemes?

Accelerator Group for LHeC LHeC Meeting at CERN; October can one think about a ring-linac option?:  absolutely!  civil engineering probably comparable to ring-ring-option  luminosity reach comparable to ring-ring option (F. Zimmermann)  interesting intermediate electron linac installation (step to ILC/CLIC)  no need to by-pass other experiments and to worry about interference  no worries related to path length differences

Accelerator Group for LHeC LHeC Meeting at CERN; October future steps and help: (all names only suggestions for CERN contact):  installation in IR2 or IR8: experiments and TS-LEA & TS-IC  acceptable radiation dose for LHC dipole magnet: and specification of e-beam energy: AT MCS / MEL; A. Hoffmann?  space requirements for RF installation: AB-RF  space requirements for magnet power converter: AB-PO  potential injection line layout: Helmuth Burkhard  potential ring lattice and by-pass configurations and operation requirements (path length etc.): Albert Hoffmann; John Jowett  potential magnet design: AT MEL (Willi Kalbreier)  linac-ring option: F. Zimmermann; Turkey; Cockcroft laboratory