P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 1 Outline  The Tevatron oWhat are the issues? oWhat is the plan for the immediate future?  The LHC and its upgrades oWhat upgrades are possible? oWhen do we start, and what is happening now?  What are the steps beyond that? oWhat are the possibilities for hadron colliders at higher energy? oHow do they compare in utility and cost?  Is there a sensible plan for HEP that includes hadron colliders? oHow can we improve the planning process?

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 2 Motivation  Hadron colliders are the discovery machines of high- energy physics. oTevatron oLHC & LHC Upgrades oVLHC  These colliders have much in common, but the ultimate performance of each is determined by different phenomena. oTevatron: Ability to produce, cool and deliver anti-protons oVLHC: Synchrotron radiation & IR debris power oLHC: In between - synch. rad., beam-beam interaction, ?  Careful analysis of these differences will help us construct the right plan.

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 3 Tevatron Performance  Run II has not yet reached its expected luminosity performance oThe luminosity is determined by proton & antiproton intensities at collision  there are indications of beam-beam limitations –Lifetimes and emittance growth in presence of other beam oThe efficiency for delivering both proton and pbar beams to collision is not yet reliable  There is now a plan to fix some of those problems. oImproved instrumentation to help understand the issues oImproved “housekeeping” to make operation of the whole complex more robust oImproved antiproton production and cooling oImproved transfer efficiencies and reduced emittance blowup

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 4 Tevatron Run II Peak Luminosity

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 5 Tevatron Luminosity vs. Pbars at Low Beta Runs

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 6 Tevatron Pbar Efficiency, Stack to Low Beta

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 7 Tevatron What’s the Plan to Do Better?  The Run II Luminosity Upgrade plan concentrates first on things that will improve efficiency oBeam position monitor and other instrumentation upgrades oDampers in MI oRe-alignment of Tevatron and Pbar source oReduce MI cycle time for Pbar production  Completed in 2004 oSlip stacking of protons in MI and pbar target sweeping oInitial pbar acceptance improvements and Debuncher cooling upgrade  Completed in 2005 oRecycler Ring with electron cooling integrated into operation oRapid transfer of pbars from Accumulator to Recycler oAccumulator stacktail cooling upgrade  Completed in 2007 oPbar production acceptance upgrade with higher-gradient lithium lens oIncreased helical beam separation oIntroduction of active beam-beam compensation

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 8 Tevatron Projected Integrated Luminosity

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 9 LHC Luminosity Upgrade - Why & When

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 10 LHC Luminosity Upgrade Work has started  HEPAP put R&D for a luminosity upgrade in its highest priority category: o “The science of extending exploration of the energy frontier with the LHC accelerator and detector luminosity upgrades is absolutely central. The R&D phase for these will need to start soon if the upgrades are to be finished by the present target date of 2014.”  From the High-Energy Physics Facilities of the DOE Office of Science Twenty-Year Road Map, HEPAP report to the Director of the Office of Science, 17 March  Technical work has begun in the U.S. within the LHC Accelerator Research Program (LARP) collaboration of DOE national labs - BNL, Fermilab & LBNL oReceived a favorable recommendation from a DOE review in June, 2003 oWorking on projects to help bring on the LHC quickly and efficiently  Participate strongly in commissioning and in some instrumentation oWorking on magnet R&D and accelerator design to provide fully integrated interaction regions suitable for ultra-high-luminosity operation

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 11 Quads 1stDipoles 1st Quads betweenTwin Quads 1st Twin Dipole 1st LHC Luminosity Upgrade Some Possible Upgraded LHC IRs

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 12 LHC Energy Upgrade  What about an LHC energy upgrade? oWhereas a luminosity upgrade is relatively cheap, quick and non- disruptive, an energy upgrade is not an upgrade — it is an entirely new collider — and, it will probably need a new injector, too oThe best performance from Nb 3 Sn magnets will result in only a 70% increase in energy oThe R&D to develop robust and cost-effective magnets at the highest field will take a long time and be very costly. oIt will be expensive and risky for little return  A staged VLHC is a better path. oHigher energy per $ or €, even in its initial stage oUpgradeable to > 200 TeV (cm)  The freedom to make tradeoffs between tunnels and technical components is a powerful tool to reduce cost and improve performance.

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 13 Design Study for a Staged Very Large Hadron Collider Fermilab-TM-2149 June 11,

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 14 VLHC Conclusions (1)  A staged VLHC starting with 40 TeV and upgrading to 200 TeV in the same tunnel is, technically, completely feasible.  There are no serious technical obstacles to the Stage-1 VLHC at 40 TeV and luminosity. oThe existing Fermilab accelerator complex is an adequate injector for the Stage-1 VLHC, but lower emittance would be better. (We should take this into account if Fermilab builds a high-power injector) oVLHC operating cost is moderate, using only 20 MW of refrigeration power, comparable to the Tevatron. oImprovements and cost savings can be gained through a vigorous R&D program in magnets and underground construction.

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 15 VLHC Conclusions (2)  The construction cost of the first stage of a VLHC is comparable to that of a linear electron collider, ~ $4 billion using “European” accounting. oFrom this and previous studies, we note that the cost of a collider of energy near 40 TeV is almost independent of magnetic field. oA total construction time of 10 years for Stage-1 is feasible, but the logistics will be complex. oMaking a large-circumference tunnel is possible. A number of different possibilities in the Fermilab area were studied.  Managing such a large construction project will be a challenge.  The political issues associated with a large tunnel must be handled with care. oBuilding the VLHC at an existing hadron accelerator lab saves significant money and time.

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 16 The Staged VLHC Concept  The Vision oBuild a BIG-circumference tunnel. oFill it with a “cheap” 40 TeV collider. oLater, upgrade to a 200 TeV collider in the same tunnel.  Spreads the cost  Produces exciting energy-frontier physics sooner & cheaper  Allows time to develop cost-reducing technologies for Stage 2  Creates a high-energy full-circumference injector for Stage 2  A large-circumference tunnel is necessary for a synchrotron radiation-dominated collider.  This is a time-tested formula for success Main Ring  TevatronLEP  LHC

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 17 VLHC Parameters

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 18 VLHC Tunnel Cross Section

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 19 VLHC Synchrotron radiation  Synchrotron radiation masks look promising. They decrease refrigerator power and permit higher energy and luminosity. They are practical only in a large-circumference tunnel. A “standard” beam screen will work up to 200 TeV and 2x Beyond that, the coolant channels take too much space. A synchrotron radiation “mask” will allow even higher energy and luminosity. Coolant

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 20 P SR 2 t sr Int/cross < 60 L units cm -2 s -1 VLHC Optimum Field

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 21 VLHC Total collider cost based on SSC cost distribution

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 22 Stage-2 VLHC Conclusions  The Stage 2 VLHC can reach 200 TeV and 2x10 34 or more in the 233 km tunnel.  A large-circumference ring is a great advantage for the high-energy Stage-2 collider. A small-circumference high-energy VLHC may not be realistic. oThe optimum magnetic field for a TeV collider is less than the highest field strength attainable because of synchrotron radiation, total collider cost and technical risk. 10 T < B < 12 T appears optimum for 100 TeV < E cm < 200 TeV  The minimum aperture of the magnet is determined by beam stability and synchrotron radiation, not by field quality.  There is the need for magnet and vacuum R&D to demonstrate feasibility and to reduce cost. oThis R&D will not be easy, will not be quick, and will not be cheap.

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 23 VLHC Next Steps  There will be a VLHC Physics Workshop this year. oDate: October , 2003 at Fermilab oOrganizers:  Uli Baur SUNY-Buffalo Contact:  Chip Brock Michigan State University  Chris Hill Fermilab  Gian Giudice CERN  Paris SphicasCERN

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 24 The HEP Plan  We are on the verge of important discoveries oThere are many hints that great physics is just over the horizon — understanding EWSB, neutrino mass, dark energy, dark matter and more. o An exciting time.  The possibilities for new HEP tools are excellent oRun II is progressing (with some difficulty) oLHC is being built (with the usual problems) oA renaissance in neutrino physics (New stuff) oA linear collider is being considered (and might start in 5 to 10 years)  Should we include a VLHC in this plan?

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 25 VLHC in the HEP Plan  Why do we need to include the VLHC in the HEP plan? oIf we believe that we may eventually want higher-energy collisions at high luminosity, we will almost certainly need a VLHC.  The timing and eventual existence of a VLHC will depend on decisions about all other multi-billion-dollar facilities including a linear collider. oIf a linear collider is built in the U.S. for billions of $, the U.S. is unlikely to spend billions on a VLHC until many years later. oThe U.S. has the best combination of resources, infrastructure, space and geology for a VLHC. It is difficult to builda VLHCt anywhere else. oA significant energy upgrade of the LHC will be very costly and very risky, for very little gain. oResult: A long delay to higher energy

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 26 The HEP Planning Process  We need to reexamine our strategy for progress, planning and politics, not only for the VLHC, but for all large facilities.  Big HEP instruments require more than business as usual oWe need a global strategy derived from a large vision of scientific goals — the “Science Roadmap.” Sell the science, not the instruments. oThink of the facilities as missions along the way to the science goals. oWe need a fair and open mechanism to modify the roadmap and the plan as results dictate. oWe will be competing with other large science facilities, or even non- scientific projects for government support. oWe must include a range of scientific disciplines and high-level government policy makers from the beginning of planning.

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 27 A Global HEP Strategy  Why do we need a global strategy? oBig HEP instruments are too costly to be planned, built and operated nationally or regionally. oHEP instruments are complex and take a long time to design and build. Everyone must be involved; everyone must help. oInternational collaboration has many political, human and scientific benefits beyond cost-sharing.  While we’re planning, important instruments are missing from the existing plans. oWhat about underground labs, super neutrino beams, astrophysics experiments or R&D for the future? All these should be in the plan, and all should be part of a Global Strategy.

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 28 A Word About R&D  The machines and facilities we are talking about are costly and complex. oMistakes and delays are potentially very damaging financially, politically and scientifically. oPolitical and financial recovery is difficult and time-consuming. oIt takes longer than you think to develop the components of a cutting-edge collider.  The R&D investment for future HEP instruments will be much greater than we are accustomed to.

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 29 Conclusions  The most important requirement for the survival of HEP is worldwide cooperation resulting in a global strategy based on a visionary science roadmap. oSell the science, not the instruments oThe goals should be truly large and visionary, and the instruments missions along the way.  The parameters and schedule for a VLHC will depend on the timing and location of all other large facilities. The global plan should recognize these couplings.  If we ever want to build a VLHC, or any other large facility, we need to have a vigorous R&D program now. o The technology is very challenging, and the penalty for failure will be severe.

P. Limon HADRON COLLIDERS July 17, 2003 EPS 2003 Aachen 30 Last Slide