Very Large Hadron Collider“Don’t eat the your seed corn!”

Ernest Malamud

ffffFermilab Accelerator R&D Oversight Group

September 30, 1999 (1st meeting)

Presentation

Ernie MalamudIntroductionSummary of budget requestsA few details not covered by my colleagues

Peter LimonHigh-field R&D programMaterials developmentConnections to long-term goal of building vlhc

Bill FosterLow-field R&D programConnections to long-term goal of building vlhc

A couple of possible intermediate steps -- byexploring these in detail, one betterunderstands technical challenges and costs

Gerry JacksonThe Energy Tripler

Bob NobleThe Tevatron TriplerA few concluding remarks

We will address the points in Steve’s memo:Long term goals of the R&D programR&D goals for FY’00Required M&S funding to meet these goalsRequired staff support to meet these goals

What is vlhc?

National collaboration Mission StatementThe Steering committee for a future very large hadroncollider coordinates efforts in the United States toachieve a superconducting proton-proton collider withapproximately 100 TeV cm and approximately 1034cm-2sec-1 luminosity.

The U.S. site of the vlhc is assumed to be Fermilab.

Using a nominal 20x in dynamic range: 150 GeV MI → 3 TeV vlhc Booster 3 TeV vlhc Booster → 50 TeV vlhc

Lots of progress

Discussions of the next “energy frontier” colliderIndianapolis ’94: the role of radiation damping

"New low-cost approaches to High Energy Hadron Colliders atFermilab." Mini-Symposia. 1996 APS Annual Meeting, Indianapolis.

Snowmass ’96

Very Large Hadron Collider Physics and Detector Workshop. March13-15, 1997. Fermilab

"Accelerator Physics Issues in Future Hadron Colliders." "HadronColliders Beyond the LHC." Mini-Symposia. 1998 APS AnnualMeeting, Columbus.

In response to recommendations of the HEPAP SubpanelReport on “Planning for the Future of U.S. High-EnergyPhysics, February 1998 (Gilman Panel) Steering committeefor a future very large hadron collider formed.

BNL: Michael Harrison, Stephen PeggsFNAL: Peter Limon, Ernest MalamudLBNL: William A. Barletta

James L. SiegristCornell: Gerry Dugan

Discussions underway to enlarge membership of Steering Comm.

Working Groups formed; each has now held aworkshop:

“Magnets for a Very Large Hadron Collider,”Co-convenors:

Bill Foster, Ron Scanlan, Peter WandererPort Jefferson, LI, NY, Nov. 16-18, 1998,Peter Wanderer, Chair

“VLHC Workshop on Accelerator Technology”Co-convenors:

Chris Leemann, Waldo Mackay, John MarrinerThomas Jefferson National Accelerator Facility,Newport News, VA, Feb. 8-11, 1999John Marriner, Chair

“VLHC Workshop on Accelerator Physics”Co-convenors:

Alan Jackson, Shekhar Mishra, Mike SyphersThe Abbey, Fontana, WI, Feb. 22-25, 1999Mike Syphers, Chair

VLHC Annual MeetingNaval Postgraduate School, Monterey, CAJune 28-30, 1999Bill Barletta, Chair

Annual Report setting R&D goals for next year expected Oct. 15.

Proceedings of the 3-workshops -- http://vlhc.orgCompilation of papers -- http://www-ap.fnal.gov/VLHC/

Tentatively planned for 1999-2000 a similar set of workshopsand an annual meeting covering new work

Why VLHC?

• Hadron Colliders are the "Discovery Machines" for HEP.

• They probe deeper than any other type of accelerator.

• The W and Z were first observed at the SppS.• The top quark was discovered at the Tevatron.• It may be possible to discover Light Higgs and SUSY

particles at the Tevatron in Run II.• LHC will extend the mass reach with 7x in Ecm.

Luminosity

“Eichten, Hinchliffe, Lane, Quigg” (1984) made the case for a richphysics menu for the SSC at 40 TeV Ecm and 1033.

A 100 TeV vlhc is a factor of (2.5)2 = 6.25 in s. Thus 1034 is theappropriate figure to set as a working parameter.

The discovery reach of such a machine is enormous.

The “Giant Microscope” andPublic Support

We need to learn how to communicate better to ourconstituencies. The giant “microscope” metaphor is oneway.

At 1034 a 100 TeV vlhc can “see” contact interactions at a scale of>32 TeV (Bauer & Eno),

. . . . perhaps as high as the Ecm or Λc ~ 100 TeV 1/Λc ~ 2 x 10-19 cm σ ~ 1/Λc

2 ~ 40 fb

1 year (30% duty cycle) at 1034 yields 100 fb-1 or 4000 events

Today the luminosity of 1034 is detector limited.

With history as a guide, 1-2 decades after the machine hasoperated at 1034, major detector and accelerator upgrades willtake place raising the luminosity to 1035 or higher.

The main accelerator upgrade may be to the abort systembecause of the large stored energy in the beam; however, by thenit is likely that brighter beams will be achieved by new coolingmethods, making this problem easier to cope with.

Generic Accelerator Tunneling R&D at Fermilab****DRAFT PRE-PROPOSAL G.W. Foster/M. May Aug 99****

10 mi.

10 mi.

10 m

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10 m

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10 m

i.10 mi.

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10 mi.

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40 TeV

10 mi.10 mi.

0.5-1.5 TeV

6 TeV

10 mi.10 mi. Dual Tunnel

Not only the tunnel is “generic”Much of the machine/magnet design is “expandable” toother energies and geometries

Assume• One new tunnel (for now)• Go off-site (find out if this is possible)

150 GeV↓

3 TeV2.0 Tesla93% pf↓

C = 38 km

1 TeV (replace later)↓

20 TeV2.0 Tesla93% pf↓

C = 225 km• continuum between these• much 3 TeV/2T work applies to other scenarios• however, there is a break point in this continuum

• ~ 0.5 B$ ??• modest “niche”

experimental program

• higher than LHC• physics case easier to

make• might be “saleable”

politically -- USA#1

Upgrade path: when high field magnets available• Single turn injection• Modest dynamic range• Argues for a bigger circumference tunnel

12 T Magnets, 72% pfE = 15 TeV

Ecm = 30 TeV2 x LHC

12 T Magnets, 72 % pfE= 93 TeV

Ecm = 186 TeV(may not be feasible because

of synchrotron radiation)

Magnets: the heart of the matter

Recently several schemes have evolved that utilize lowand high field magnets in a vlhc complex

Low-field, 2T, iron-dominated gaps• possibly lower $/TeV including tunnel -- one of the

R&D goals is to determine this cost• faster cycling; more suitable as an injector• possible fixed target mission for intermediate

machineHigh-field, 10-12 T, conductor-dominated gaps

• requires development of new materials; longertime-scale

• smaller geographical extent; possibly less difficultpolitically

• at collision energy, advantages of synchrotronradiation damping

Magnets: the heart of the matter

Factors in choosing the magnet strength• collider energy• accelerator physics issues• superconducting material availability and cost• magnet costs• synchrotron radiation

choosing the collider energy allows one to examine therole of synchrotron radiation in more detail

For a 50 TeV + 50 TeV collider

Low-field (2.0 T superferric):• Damping time too long to be helpful• However, allows alternating gradient structure with

no problems from anti-damping

High-field (> 10 T):• synchrotron radiation puts power into the cryogenics• synchrotron radiation makes the beam emittance smaller

Other factors that need evaluation to properly understand the role ofsynchrotron radiation:

• ground motion• dipole field noise• intra-beam scattering• quantum fluctuations in the synchrotron radiation• fill and ramp times (before synchrotron radiation comes into play)

Magnet R&D programs:different paths to a common goal

SuperconductorsLow field

• NbTi is ideal for the low-field vlhc• Jc at low field has increased 10x since Tevatron built

(driven by MRI market)• Cost is probably < $1 /kA-meter

High, very high field Material development is the key issue• HTS: BSSCO, YBCO• LTS: (A15 Conductors) Nb3Sn, Nb3Al

FermilabLow-field NbTi superferric B ~ 2 T

Other interesting ideas forsuperferric machines: KEK, JINR

Brookhaven

Very high field B ~ 12.5 T

Goal: based on future developmentof YBCO"conductor friendly" common coil

FermilabHigh-Field Nb3Sncosθ

B ~ 11 T

Lawrence Berkeley Lab

Very high field B > 13 T

various materials being tried:Nb3Sn, Nb3Al, BSCCO

"conductor friendly" common coilTexas

Stress managementB ~ 16 T

The Fermilab low field (2.0 T, transmission-line magnets) programis making progress.

Test loop in the MW-9 building built using surplus SSC conductor.

Tested successfully at 100 kA August 30, 1999

The loop has a removable 4-m section in which varioustransmission lines can be tested.

Excellence of the Fermilab site

• Existence of the injector chain• Excellent Geology

Fermilab region geology

• predictable rock and tunneling conditions, relativelyhomogenous rock mass – extensive local experience in theTARP tunnels (> 100 miles under Chicago)

• no settlement problems at the depths being considered

• rate of movement of groundwater in the dolomite layer we areconsidering for the collider is very small (aquatard)

Tunnels and Choice of tunnel size

• lowest cost• room for other machines• Sufficient room for installation and maintenance• Operating the machine will certainly imply the use of robotics; just

how much robotics is used is a matter of economics.

“Conventional” TBM/Conveyor belt tunneling

♦ we have used the specific siting and depth of the 3-TeV low-field tunnel as a model to investigate tunnel costs

♦ ♦ we are using detailed cost model from Kenny Construction to

understand cost drivers

♦ a recent study by the Robbins Company gives optimism thatthis cost (per meter of tunnel) can be significantly reduced

Exploration of new methodologies in tunneling and muck removal