CLIC-ILC Collaboration Update

1. CLIC-ILC Collaboration Update Mike Harrison PAC Meeting, Taipei May 19/20, 2011

2. The CERN recent medium term (5 year) plan – May 2011 shows high priority for Linear Collider collaboration for the future • The science drivers for the 2011 MTP: • … LHC Ops…., the fixed target program and ….. • “This MTP is science-driven secondly by the preparations for the longer-term aim of ensuring that CERN remains the main global accelerator laboratory at the energy frontier: • R&D for CLIC in the framework of a world-wide collaboration, leading to a Conceptual Design Report in 2011/2012; • enhanced CLIC – ILC collaboration, including detector R&D and preparation for the Conceptual Design Report; • R&D for superconducting high-field magnets for a possible higher- energy proton collider, HE-LHC, if necessitated by the physics; and • R&D for high-power proton sources, such as the high-power superconducting proton linac (HP-SPL), in line with European participation in neutrino physics.”

3. The Accelerator Inspired Working Groups • The current technical working groups are • Beam delivery systems & machine-detector interface • Civil engineering and conventional facilities • Positron generation • Damping rings • Beam dynamics • Cost & schedule • In addition to the General Issues working group

4. Beam Delivery System & Machine Detector Interface There is a major collaborative activity based on the ATF2 facility. Interaction region beam stabilisation is a huge challenge for CLIC. ATF2 was damaged by the earthquake but is a high priority at KEK to resume operations. A possibly bigger issue is the future program beyond 2012. These is significant interest from CLIC to also continue with this work. A common beam dump design for both CLIC & ILC is under investigation. A NIM report covering energy deposition, thermal and hydraulic effects, and pressure waves (2D & 3D) by a team from BARC, SLAC, RHUL & U of Manchester is in the offing. Push-Pull & MDI related joint studies are in progress – see earlier talk by Juan.

5. Civil Engineering & Conventional Facilities This WG is essentially a single group and represents the closest collaborative entity we have at this point. There are using a common approach to safety etc….

6. Civil Engineering & Conventional Facilities ARUP is an engineering consulting firm (London) that John Osborne has been in contact with to do some detector hall work that would apply to both CLIC and ILC.  There are currently has four proposals in hand to do various studies: 1.       Design study for the detector platform design (CLIC and ILC) 2.       Development of a model to study the rock mass behavior in the area of the interaction region (CLIC and potentially ILC) 3.       Study of a passive isolation slab design for the main linac tunnels adjacent to the interaction region (CLIC) 4.       Review of the interaction region overall layout (CLIC and potentially ILC) 

7. Positron Generation: Investigation of Undulator Based Polarized e+ Source for CLIC W. Gai, W. Liu/ANL L. Rinolfi/CERN

8. Positron Generation: Polarization and Yield Calculations:Undulator (ILC): K=0.9, lu=1.5cm, L=100 mAMD: 7T-0.5T in 20cmCapturing RF: 2GHz, 25MV/mTarget: 1.4 cm Titanium Drive Beam Energy: 250 GeV W. Gai, W. Liu/ANL L. Rinolfi/CERN

9. Damping Rings Strong synergy and collaboration in the e-cloud CESR-TA program – Mark’s talk Beam physics – IBS in ultra low E regime. First experimental run Instrumentation – optical diffraction radiation monitor (beam size) in production via RHUL/CERN for 2012 installation IBS simulation with SMAD code with INFN & SLAC

10. Damping Rings The CLIC/ILC e-cloud collaboration is transforming itself into the global LOWeRING collaboration

11. Cost & Schedule Working Group The Cost & Schedule WG planned activities have been hampered by the lack of a released CLIC cost estimate. The original plan was to validate the CLIC 3TeV estimate in the Spring of 2011 and the CLIC 500 GeV costs were to be scaled from this number. As the preliminary estimates of power consumption and investment cost are high for the CLIC 3TeV, the decision was taken not to release the cost estimate pending a more precise assessment of the maximum energy of the machine. At this point the plan is to look at CLIC costs by the end of the calendar year. It is likely that there will be a CLIC 1TeV estimate in addition to that of CLIC 500 GeV No plans yet for a similar scrutiny of the ILC TDR estimate but presumably there will be.

12. The General Issues Working Group As reported at the last PAC meeting the General Issues Working Group did indeed produce an interim report at the end of 2010. The report was formally presented to the CLIC Collaboration Board and ILCSC in February. The main recommendations of the report followed the outline given to the PAC in November

13. General Issues Working Group – reply (to the interim report) from Steiner Stapnes, heavily paraphrased • Presented to the CLIC CB on Feb 17th ………The three main topics of discussion ….. • The wish to consider if there are specific site requirements for CLIC • The need to understand the system tests needed for both projects - our discussion concentrated the CLIC side of this • The recommendation to present a cost band up to 1 TeV • “In particular on these three items we will follow up in more detail in our project planning discussions and it is useful to have these issues identified in your report.” • “Concerning future work of the WG we are happy to discuss this further with you. One rather obvious first point is to make sure that the points raised in the current report are followed up or at least discussed carefully, secondly to consider if more R&D areas can benefit from common working groups, and thirdly to continue to develop common understanding and language to be able to compare and discuss the strengths and weaknesses of both technologies in an open atmosphere. “ • “Moving towards a more combined Governance model is an underlying theme but clearly there are several processes in this area, and one has to be careful to discuss such a complicated issue in the right place and at the right time. Your WG can nevertheless contribute very constructively to such a process if the discussion and suggestions are made in coherence with larger discussions in the community and in other committees.”

14. General Issues Working Group – reply (to the interim report) from Jon Bagger (still in progress) The official response from the ILCSC is still in progress so there are no direct quotes. Generally Jon singled out similar recommendations to Steiner. Jon took exception to the aspects of the medium term schedule developed by the WG in spite of the caveats given. Schedules (that show construction start or project decision points) are very sensitive and the WG will be more circumspect in any future reports ….. I think.

15. General Issues Working Group: Future topics (work still in progress) • Issues part of project implementation plans • Siting • criteria and constraints • CLIC specificities • Preparation of technical procurement • Considerations of mass producing hi-tech components • QA, industrial follow-up • Decision point for the LC • Points of comparison between the two approaches • Physics reach • Maximum energy: in relation to first LHC results • Energy staging and upgradeability • Luminosity (incl energy spread & background) & polarization • Lower-energy operation, energy fine scans • Accelerator technology • Explore (& compare ?) strength/weaknesses of the two approaches • Comparative reliability • Future technology development? • Cost & power estimates • Topical joint WGs • Follow-up of existing ones • ½ day topical workshops at LC meetings : • RF power sources • High surface E-M fields • Beam instrumentation • Conclusions Topics in green - another interim report in 2011 Topics in blue - the final report in 2012

16. Decision point for the LC • 2½ key facts are needed • Is there a light (<200 GeV/c2) Higgs? • Is there New Physics (below 1 TeV)? • If yes, what is the energy range? • Note: • It does not matter much from the point of view of defining the decision point what the answers to these questions are – only that we know them! • The 1st question may be answered by end 2012 • The 2nd question may be answered by end 2011 • The ½ question may not be clear for some time • We need to define criteria for making a “fact” • Is 3s enough for evidence? • Is 98% enough to exclude? • Reach of LC wrt HE-LHC or HL-LHC?

17. Comments and proposals • Do we need the answers to both to proceed? • (KJP) yes (politically) • Is the European Strategy update a constraint? • (KJP) yes • If either or both questions are answered before the Strategy update workshop, we should • Encourage the Americas & Asia to update their strategies • Organise input to these discussions • Plan for a “community workshop” in early 2012 (March?) • If there is no reliable information by March 2012 • Be prepared to organise a quick workshop between March and the Strategy update workshop if evidence emerges • Make plans for a major “community workshop” in early 2013 to review the situation • [this will either define the LC parameters or address the crisis] • “Community workshop” – a sort of Snowmass

18. Conclusions The Linear Collider collaboration is working at the grass roots level. We may tweak the organisational structure a little (i.e. create one) The General Issues Working Group does appear to have a legitimate role in the collaborative process. The ~2012 co-incidence between the EU strategy report, the CLIC CDR, the GDE TDR, and the LHC first physics run could certainly change the landscape in a significant way. There is evident interest on both sides of continuing to develop the LC collaboration in the future, post GDE. We will need to consider how to do this soon.