Reactor Q 13 in the USA

July 28, 2004 Tim BoltonNUFACT 2004-- OSAKA

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Reactor 13 in the USAWill discuss

Physics case for a “medium” sin2213≤0.01 reactor experiment.

Status of “Midwest” 13 project at Braidwood, Illinois.

Will not discuss

Highly advanced, but regrettably suspended Diablo Canyon project.

American involvement in Double-Chooz, Daya Bay, KASKA, and other international efforts beyond US borders.

US political situation, reactor or otherwise.


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Physics Case for sin2213≤0.01Reactor-only:

Uniquely clean and precise measurement of 13.

Medium Braidwood style experiment exploits both rate and shape.

Reactor+T2K/Noa (M. Shaevitz)

Medium experiment resolves (45±23)° degeneracy for 23.

Small D-Chooz type experiment may leave ambiguity.

But for T2K/Noa with + running:

Minimal impact on mass hierarchy from reactors.

Modest impact on CP violation from reactors.

Caveat: A D-Chooz null result would make this physics tough for everybody.Huber et al.

hep-ph/0303232


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M. Shaevitz Study:

sin2213(true)=0 sin2213(true)=0.05

Reactors get 13!


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23 45 deg. reflection degeneracy

1.5% sin2223

Medium Braidwood-like reactor + / off-axis resolves ambiguity.

Result holds even without high precision 23.

D-Chooz may leave degenerate solutions, even with precise 23.


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Precision MeV Physics

104 105 e interactions in near detector precision!

e.g.: RJ ee ee ep e n

(J. Conrad, et al.)

Robust observable, first order flux cancellation.

Addresses “NuTeV anomaly” at NuTeV precision.

Interesting EW tests (ST plane) at Q2=0.

Challenging singles measurement, needs:

•Depth to suppress spallation.

•Borexino-level radioactivity.

•Use of low background energy window.

•≤ 1% systematics (calibrations).


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Braidwood Experiment Details

People.

Location.

Layout.

Detectors.

R&D.

Schedule.


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ANL: M. Goodman, V. Guarino, D. Reyna

Chicago: E. Abouzaid, K. Anderson, E. Blucher, J. Pilcher, M. Worcester

Columbia: J. Conrad, J. Link, M. Shaevitz

FNAL: L. Bartoszek, D. Finley, H. Jostlein, C. Laughton, R. Stefanski

Kansas State: T. Bolton, J. Foster, G. Horton-Smith, D. Onoprienko, N. Stanton

Michigan: B. Roe

Oxford: S. Biller, N. Jelley

Pittsburgh: D. Naples, V. Paolone

Texas: J. Klein

Midwest 13 Collaboration


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Location<50 km from two US national labs: Fermilab + Argonne National Lab.

ANL has ~50 years of reactor expertise.


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Reactor Complex

But:

Cost risk associated with “green field” site.

Reactor managment presently encouraging, but tough decisions lie ahead.


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Basic Scheme

One near detector at ~270m; at least two far detectors at ~1700m.

Near and far detectors at 450 mwe depth (if bore hole samples confirm).

Identical 6.5m diameter 3-zone (a la D-Chooz) spheres.

Gd-loaded LS fiducial in 25-50 ton range, depending on buffer optimization.

LS -catcher + non-scintillating buffer.

Passive and active external shielding.

Detectors fully constructed at surface sites.

Detectors lowered down shafts (a la KASKA).

Detectors movable via surface transport for cross calibration.


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Layout Schematic

Note: reactor management has agreed to shorten near access tunnel length from 300m to 50m ($$$!).


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Aerial View


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Mechanical Conceptual Design

Lifting points allow full assembly at surface.

Permits far detectors to move to near site for cross calibration.


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“Hoist and Roll” Scheme

“Common” procedure in industry.

Considerably cheaper than tunneling.

Favorable terrain at Braidwood site using truck on gravel road or rails, depending on load stresses.

Clearly requires careful design/implementation studies (underway).

Left: 750 ton test lift by crawler crane.

Right: 200 ton drilling equipment on gantry + self-propelled platform trailer. (ALE Lastra).


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Hall Layout


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Acrylic Sphere Support

Multiple <2.5 cm dia. Spacers.

Assumes simultaneous filling for neutral buoyancy.

Ongoing work at ANL, U. Chicago.


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Software

Parametric and full G4 hit-level simulations (D. Onoprienko).

Good agreement with Chooz measurements (after some pain).

Optimizing geometry (RFID vs. R-C vs. RBUF).


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Cost/Schedule Detailed estimate prepared for underground construction at Braidwood site prepared by independent consultants (Hilton and Associates, Inc.).

Included civil construction; outfitting with pumps; elevators, ventilation, etc.; and decommissioning costs at experiment end.

Permanent surface structures, detectors not yet included.

Detail level sufficient for re-scaling to optimized layouts.

•First iteration: two 300 mwe shafts, different detector hall designs, 300m tunnel for near site access:

$35M cost, 39 month construction schedule.

•Revised layout: considerably shortened near access tunnel, 450 mwe depth (160m rock+20m soil).

Cost in $25-35M range, <24 month construction schedule.

Detector cost (from MiniBoone scaling) ~ $8M/detector.


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Summary

Compelling physics case for a sin2213≤0.01 experiment.

•Medium scale reactor best short-term choice.

•Importantly extends Double-Chooz capabilities (provide ~3×better sin2213 sensitivity; with LBL, resolve 23 45 degree reflection degeneracy; open new field of precision MeV physics.)

Braidwood site an attractive choice:

•High power modern reactor complex with cooperative management.

•Simple layout with deep near site and possibility of movable detectors.

•Access to national lab infrastructure.

Current status:

•Active lab + university-based R&D.

•Bore hole study at Braidwood soon that follows up detailed costing studies.

•Preparing R&D proposal this Fall towards full proposal in 2005.

Documents

Reactor Q 13 in the USA