1. Accelerator Group for LHeC LHeC Meeting at CERN; October 2007 1 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

2. Accelerator Group for LHeC LHeC meeting at CERN; October 2007 2 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!)

3. Accelerator Group for LHeC LHeC Meeting at CERN; October 2007 3 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  * ?)

4. Accelerator Group for LHeC LHeC Meeting at CERN; October 2007 4 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!

5. Accelerator Group for LHeC LHeC Meeting at CERN; October 2007 5 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?

6. Accelerator Group for LHeC LHeC Meeting at CERN; October 2007 6 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

7. Accelerator Group for LHeC LHeC Meeting at CERN; October 2007 7 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