Mu2e, August 15, 2007 E Prebys 1

The Steering Group and mu2eThe Steering Group and mu2e

Eric Prebys

Mu2e, August 15, 2007 E Prebys 2

GeneralGeneral

• The Fermilab Steering group has presented its report• Priorities (post-collider):

LHC Support ILC R&D R&D for a new facility to enhance the lab’s “intensity

frontier” capabilities at 8, 120, and 800 GeV, primarily for neutrino physics

• An 8 GeV linear accelerator based on ILC technology, currently referred to as “Project X”

• Could be running as early as 2015 Consider other opportunities to exploit existing facilities in

the near term (no priorities given):• Mu2e• Neutral K-> (KOPIO) at 8 GeV (uses Debuncher)• Charged K-> (KTeV-II) at 120 GeV (uses TeV as stretcher) scattering at 800 GeV (NUSONG), resurrent TeV fixed target• Physics with antiprotons • Possibly SNuMI (if ILC only slightly delayed and/or built

offshore)– Alternative to Project X !!

Main thrust of report

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Specific Mentions of mu2e (talking points)Specific Mentions of mu2e (talking points)

• Discussed under 3.2 (Precision Physics) “An intense 8 GeV proton beam and the Accumulator

and Debuncher rings, available after the end of antiproton production for the Tevatron Collider program, would make possible an LFV search experiment that would make, by far, the single most sensitive search for any LFV process. “

• In appendix D (under “Precision Physics Experiments with Muons”) The MECO design has been reviewed for cost and

technical feasibility in detail, and a new experiment based on MECO could be developed into a reviewable project at Fermilab with about one year of effort. Physics results at sensitivity below 10-16 would follow 4-5 years of construction and 2-3 years of running. Upgrades to use a more intense beam following the SNuMI or Project-X construction would be studied and then implemented following the first physics running period.

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Proton Driver vs Project XProton Driver vs Project X• Proton Driver

8 GeV H- linac feeding directly into Main Injector

Tailored for ~2MW at 120 GeV• ~1.5E14 protons per pulse

High energy end uses beta=1 ILC cavities .5-2MW total 8 GeV proton capacity Problems:

• Integrated charge/pulse about 3 times higher than ILC -> very different beast.

• Excess proton capacity (long pulses of H- ions) difficult to transport and use.

• Project X Highest 6 GeV exactly like the ILC

• 9 mA x 1ms• 5 Hz

Strip/inject into Recycler Inject 3 pulses worth (1.7E14 protons) into

the Main Injector ever 1.4 second cycle Leaves up to 4 pulses (200 kW) for other

uses This batches are stripped and stored in the

Recycler, where they can be rebunched as needed

LAB

2015

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Project X and mu2eProject X and mu2e

• Availability of up to four linac pulses @50kW each Compare to max ~35kW with base line scheme

• Probably cannot slow spill from Recycler Cannot design around Project X, even if we

wanted to (which we don’t !!!)

• Given the current enthusiasm for Project X, we can’t ignore it, but it shouldn’t become too much of a distraction: Boiler plate in LOI More detailed discussion of detector and target

upgrades in proposal

• Must transfer batches to Accumulator and handle more or less as we handle Booster batches Increased intensity has

implications for target and detector

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Important Mistakes in Report (wrt mu2e)*Important Mistakes in Report (wrt mu2e)*

• Some confusion about 8 GeV proton availability in NOvA era Section 4.3 incorrectly states that a program protons

debunched and extracted proton beam would take protons away from the 120 GeV program. In fact, that would only be true in the SNuMI scenario .

First paragraph of the "Upgrade to the Fermilab Proton Facility" section (p. 32) incorrectly states that an 8 GeV physics program cannot be supported without compromising the NOvA physics program. Again, this will not be true except under the SNuMI scenario.

• Discussion of neutral K-> experiment (KOPIO) very confusing Neglects to mention that this experiment would also

require the Debuncher Bundling it with KTeV-II in Appendix D gives casual reader

the impression it somehow uses the TeV stretcher*communicated to Young-Kee Kim

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Significant Omissions in ReportSignificant Omissions in Report

• Report generally states the impact of the near term proposals on NOvA, but make no mention whatsoever about how they compete with each other, specifically: Mu2e and KOPIO would not affect NOvA, but would

have to share protons and the Debuncher with each other (a la RSVP)

Either of these and/or SNuMI are completely incompatible with continued operation of the antiproton source.

NuSONG (800 GeV protons) and KTeV-II/SY120 compete directly with each other for use of the the Tevatrons, and make some small impact on NOvA, but do not compete directly with Mu2e and/or KOPIO