Mu2e Project Overview Mu2e WGM R. Ray 3/17/2010 13/17/2010 - Mu2e WGM

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Mu2e Project Overview

Mu2e WGM

R. Ray

3/17/2010

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Mu2e

• Our primary scientific requirement is to:

search for charged lepton flavor violation with unprecedented sensitivity. We will measure the ratio of the coherent neutrinoless conversion in the field of a nucleus of a negatively charged muon into an electron to the muon capture process:

with a sensitivity Rme < 6×10-17 at 90% CL. This is almost a four order-of-magnitude improvement over the existing limit. The observation of such a process would be unambiguous evidence of physics beyond the Standard Model.

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Overview of Mu2e• High Z target to maximize pion production• Axially-graded field to maximize pion capture

5 T

2.5 T

2 T

1 T

1 T

• Curved transport selects low energy m-

• Muon stopping target in a 2 T axially graded field to improve conversion acceptance

• High rate e- detectors in constant 1 T field.

Cosmic ray shield not shown

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Accelerator

• Mu2e uses Booster batches that are available when the Main Ring is ramping for the 120 GeV neutrino program.

Mu2e has no impact on NOvA.

• The Mu2e experiment needs bursts of protons delivered on target within a time window of ~200 ns every 1.7 s, corresponding to the revolution time of the Debuncher ring. The total number of protons to be delivered on target for the experiment is 4×1020 per year.

The Collaboration prefers a high duty factor that minimizes instantaneous rates but has never been able to quantify that requirement.

• To spread out transfers to the Accumulator Mu2e brings booster beam into the recycler, similar to NOvA, but kicks it out into the P1 line and into the pbar Accumulator.

• Accumulator beam is split into 4 smaller bunches and transferred, one at a time, into the Debuncher.

• Slow spill from Debuncher to experiment.

and Recycler

Mu2e

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Accelerator Scenario

5

Recycler

45

6

3

2

1

from Boosterto Accumulator

NOvA batch

• We thread beam in-and-out through the Recycler injection gap while NOvA beam is circulating.

• NOvA accepts 6 “batches” from Booster, then performs “slip stacking” to a slightly different energy (and hence different orbit) in order to accept 6 more later.

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Recycler

45

6

3

2

1

from Boosterto Accumulator

NOvA batchMu2e batch

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Recycler

56

4

3

2

1

from Booster


to Accumulator

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Recycler

6

1

5

4

32

from Booster


to Accumulator

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Recycler

1

2

6

5

43

from Booster


to Accumulator

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Recycler

12

3

6

54

from Booster


to Accumulator

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Recycler

23

4

1

65

from Booster


to Accumulator

After Mu2e batches have passed through, inject the last six batches for NOvA.

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Accelerator

• It is necessary to upgrade the Booster to operate at 15 Hz in order to operate any new experiments simultaneously with NOvA (MicroBooNe, g-2, Mu2e) AD has been continuously upgrading the Booster over time. This is not part of

the Mu2e Project, but we have to make sure that it happens.

• The Recycler has to be connected to the P1 line at MI-52 and an appropriate extraction kicker, identical to the NOvA injection kicker, must be fabricated and installed. There is some question about whether the fall-time of the NOvA kicker is fast

enough.

• Accumulator and Debuncher must be reconfigured. Both require new 2.5 MHz RF systems. Bunches are formed in the accumulator

and the have to be held in the Debuncher. Accumulator also requires a 53 MHz system for momentum stacking. Apertures in P1, P2, AP1, AP3 will have to be opened up to accommodate higher

beam throughput. A slow extraction scheme has to be designed and implemented in the

Debuncher.

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External Beamline

• A new external beamline from the Debuncher to the Mu2e detector hall is required. Civil construction Electrostatic and magnetic septa,

new bending and focusing elements, final focus system, optics, collimators, etc.

• To eliminate prompt backgrounds we require minimal beam between pulses. MECO spec was 10-9 (ratio of beam between pulses to beam in pulses) but the

requirement is time-dependent.• Extra beam immediately after the pulse is OK, several hundred ns after

pulse is trouble.• Necessary to monitor the beam between pulses to know how we are doing.

• Two schemes exist but neither is very advanced. Need someone to take ownership.

Beamline

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Target and Shield• Production Target

Water-cooled gold target in titanium jacket

Large Z to max. pion production Thin to minimize pion absorption Preliminary thermal analysis complete.

• Safety factor of 4• Benchmark calculations with prototype• Design review with target experts in the Fall

Production Target

Heat Shield

25 kW proton beam2.2 kW ave power in targetDesign power load 8.6 kW

• Heat Shield 76 ton water-cooled Cu and W

heat and radiation shield to protect PS coils from nuclear heating, radiation damage and quenching.

~16 kW of heat generated in shield Detailed investigation of energy

deposition underway (Mokov)• Looking at other materials

that may do a better job of absorbing neutrons.

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Accelerator Issues

• AD is very heavily committed. Getting resources will be a challenge. • If g-2 is in the mix, we do not have a working plan

Both use the pbar source and recycler, but in different ways. Some overlap. Would need a plan that allowed modifications to pbar source for each experiment

and running time for g-2. Must be consistent with CD process or funded in a different way.

• Running the Tevatron for an additional 1-2 years does not impact Mu2e unless g-2 is in the mix.

• Shielding assessment is required for pbar source. Restricted occupancy likely to be required. Active or passive?

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Solenoids• The solenoids impact everything else and drive our cost and schedule.

• We now have a significant team of people working on the solenoids including a subproject engineer and L3 managers (Great job my Mike Lamm in assembling a team).

• Mike Lamm will give you a solenoid update.

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Muon Channel

• Selects and momentum range, stops in thin target foils, and absorbs some secondaries

• Components include: Vacuum system Collimators Stopping target & monitor Pbar absorbing window Neutron absorbers Proton shield Detector support structures Muon beam stop

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Muon Channel Issues

• Losing L2 manager In talks with potential replacement

• Potential need to rotate central collimator is an unexpected complication.• Most of this L2 is optimization, engineering and integration.

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Tracker• MECO had no viable, proven tracker design and their tracker requirements

were not fully developed or documented.• The tracker environment:

For 200 ns after the arrival of the proton beam at the production target, the tracker sees a beam flash of up to 8 MHz/wire. The flash is primarily electrons.

700 ns after the arrival of the proton beam at the production target, the live gate is opened and the tracker has to be fully efficient.

During the live gate the tracker will see rates of up to 170 kHz per wire. Rate is dominated by protons which are 10x minimum ionizing.

e from m decay

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Tracker• Rate handling requirements dictates small diameter

straws and fast gas Open geometry drift chamber still under consideration.

Has obvious advantages and concerns.

• Resolution in tracker dominated by multiple scattering. Requires minimum of material and operation in vacuum.

• Sophisticated pattern recognition and fitting required to obtain precision momentum measurement. Trying to get simulations in place to evaluate this.

Going slow. Coordinate information along straw length may

help.• Pads, charge division, time division• Concern about rate performance in each case.

• Largest cost is readout electronics. Initiating work at LBL to modify BaBar Elefant chip.

• Faster clock speed• Bigger buffer• Lower power for operation in vacuum.

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Tracker R&D

• Mechanical prototypes of 2.5 m straws• Rate studies of straws• Preparing to study charge/time division.• I tracker beam test at Frascati• Investigating pads etched into straw copper

cladding.

sag of 1.3 m long triplet of BTeV straw s - no tension

-3000

-2500

-2000

-1500

-1000

-500

0

500

0 0.2 0.4 0.6 0.8 1 1.2 1.4

position [m]

gravitational sag [um]

fixed ends add center support

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Tracker Issues

• No L2 Manager. Working on solving this soon.

• Need fairly advanced simulations to choose between tracker alternatives. I’m not confident we will have these before Thanksgiving. May have to punt on

this for CD-1, make our best guess and identify unanswered questions as significant technical risks.

• We don’t know how to calibrate this device. This is a big problem. Potential show stopper.

• Need conceptual mechanical designs Tracker support Gas manifolds Electronics interface Cables/fibers/Data flow Water cooling

• Need conceptual design for electronics downstream of the modified Elefant chip.

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Calorimeter

• Calorimeter provides second independent measurement of energy, trajectory and timing. Could also be used in trigger. Can’t compete with tracker on energy resolution. Extrapolation of measured helix in tracker to

calorimeter (in space and time) may help to expose mis-reconstructed events in tracker.• This has yet to be demonstrated with simulations

• INFN is taking the lead on the calorimeter Beam test in Frascati of LYSO crystals Position and timing resolution excellent

• 50-100 ps, 3-4 mm for 100 MeV e-

Energy resolution not yet understood.

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Cosmic Ray veto

• Cosmic rays can create background Muons can decay in the detector

solenoid. Muons can interact in the stopping

target, detector or other material and make electrons.

Muons can scatter in the stopping target or other material and be mistaken for an electron.

Muons can interact in material, make other particles (photons or hadrons) which then interact and produce electrons.

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CRV Issues

• Background from cosmic rays must be << 1 event over the course of the run (2 × 107 s) MECO claimed that this required an efficiency of 99.99% for the CRV. We have

to confirm this number for our specific application. Lots of neutrons in detector hall from both targets and proton dump that could fire

the veto and significantly reduce live time.• Lots of neutron shielding• Looking at ways to reduce CRV sensitivity to neutrons.

Thicker scintillator Pattern recognition with multiple layers RPCs?

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Conventional Construction

• We need a detector hall, a connected cryo building and a new beamline.• We have to understand the shielding requirements for the proton beam and

the production solenoid. We have assumed 21 feet Drives depth of detector hall

• Trying to understand stakeholder requirements, as they are now known, so we can do the Title I design.

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Trigger and DAQ

• No work done yet on this system• No L2 manager yet.• Bob T is going to organize some engineering effort in CD to put together a

conceptual design for a trigger and DAQ system so we will have something for a CDR. CD is particularly interested in looking at a “triggerless” DAQ

• Triggerless == no hardware trigger.

• Some potential interest in DAQ from SLAC but probably no movement until the fate of SuperB is decided.

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Schedule

CD-1 CD-2 CD-3

Best guess schedule

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CD-1 Timeline

Lehman CD-1 Review March 1, 2011

Director’s Review Feb. 1, 2011

CDR complete Jan. 15, 2011

Final cost & schedule and associated documentation.

Jan. 15, 2011

L2 CDR contributions submitted Dec. 1, 2010

Director’s Design Review Nov. 1, 2010

L2 Design Reviews October, 2010

Time

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Risk Registry

Started on Risk Registry• 30 risks identified so far from half of the L2 systems

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Documentation

• Early drafts of: Quality Management Plan Project Management Plan Security Vulnerability Assessment Configuration Management and Change Management Plan Life Cycle Costs Risk management Plan Contingency Rules Integrated Safety Management Plan

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Scientific Salaries

• Until recently scientific salaries were not charged to projects Considered part of the base program.

• Drive to have some scientists on-project comes from DOE• In December, 2009 the Lab documented it’s policy

Memo from Cindy Conger, FNAL CFO, Mu2e-doc-763

• In response, I wrote a memo documenting my interpretation of the policy, Mu2e-doc-764 Project Managers and L2 managers on-project if they work for FNAL AD, TD, APC scientists working on accelerator modifications, the external

beamline, the primary production target, the proton beam absorber, extinction or any other activity generally associated with accelerator systems will be charged to the Project.

The solenoids are considered part of the detector. Scientists working on them are off-project.

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IPT and Tech Board

• IPT has been established. We have met 3 times.• One IPT meeting was devoted to NEPA

Fermilab ES&H, Fermi Site Office, Chicago office and Germantown all participated.

Trying to understand if an EA will be required or if the categorical exclusion can apply.

• Need to do pbar shielding assessment before we can make a decision

Need to schedule a follow-up meeting.

• Tech Board has been meeting for many months Current concept for the detector hall emerged from a series of intense

TB meetings Now working on WBS, resources, risks, etc.

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University Participation

• Mu2e is very Fermi-centric. Having a hard time getting universities involved.

• Universities that are involved are making a big difference Boston U Rice Virginia CUNY

• Opportunity to get some critical people at universities involved if we can provide some support to hire RAs. I have been talking to DOE about this. They are helping, but can’t do

everything we would like. Nuclear side is a problem.

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Other efforts to add people

• The Project bought out 2 Professors from teaching this year to reside at Fermilab and work on Mu2e full time. Jim Miller, BU, co-spokesperson Jim Popp, CUNY, significant collaborator on MECO

• With PPDs help, we are awarding “International Fellowships” to 3 Italians (one senior collaborator and 2 post docs) to work full time on Mu2e at Fermilab. Strengthen ties with INFN Convince them we are serious about Mu2e Hope to eventually get in kind contribution of calorimeter from Italy.

• New positions that could help Mu2e Virginia/Fermilab joint faculty/staff position on Intensity Frontier Intensity Frontier positions in CD

• With TDs help we are bringing in a senior CERN magnet and accelerator scientist to work on solenoids for a year, starting in August. Ranko Ostojic

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What is required for CD-1?A Conceptual Design• Define scientific and technical requirements

The Collaboration is expected to play a major role in this activity.• Evaluate alternatives for satisfying the requirements• Select a set of preferred alternatives• Demonstrate that the preferred alternatives satisfy the requirements.• Perform a high-level risk analysis and develop mitigation strategies• Identify opportunities for Value Management• Cost and schedule• Lots of documents and bureaucratic work.

R. Ray - Mu2e Collaboration Meeting, Jan. 7, 201036

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Requirements Documents

• Very few requirements documents have been written to date. This is the primary area where more Collaboration participation is required.

• MECO did a good job of documenting the solenoid requirements but a very poor job elsewhere.

• Mu2e is not doing much better…• I am preparing a list of necessary requirements documents that we will

show at future WGM to track progress.

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Action Items

• Find L2 manager for tracker. I am close.

• Get resources required for CD-1 into Primavera• Find replacement for Peter Limon

Current plan could fall through. No backup plan at the moment.

• Prepare list of necessary requirements documents for next meeting. Track at future meetings.