Goals and Questions for Workshopmoller.physics.berkeley.edu/~yury/mu2e/talks/bernstein1.pdf · Goals and Questions for Workshop ... C++/ROOT/GEANT4/ ... ¥ canÕt stand up and claim

R. Bernstein, FNAL Mu2e/COMET Workshop Jan 2009

Goals and Questions for Workshop

R. BernsteinMu2e/COMET Joint Workshop

LBL 23-24 Jan 2009

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Themes:

• Comparisons:

• Design of two solenoids systems

• rate, backgrounds, cost, technical complexity

• Common Problems:

• Extinction

• Calculation of Physics Processes

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Comparisons: Transport Solenoid

• Comparisons:

• Production or Capture Solenoid

• Transport Solenoid: C vs. S

• Detector: Resolution and Backgrounds

• Can we make a single, unified comparison?

• What drives cost/schedule in each design?

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Comparison of Production Solenoid

• Can we make a single, unified comparison?

• Production Solenoid

• requires

• Common models for Particle Production

• Common propagation code

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Comparison of Transport System

• COMET/Mu2e method:

• What are the advantages/disadvantages of:

• collimator and S-shape

• dipole field

• Cost/Technical Complexity?

• How much is COMET scheme driven by J-PARC configuration and would it make equal sense at FNAL?

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Detector Issues

• Central idea are the same:

• straw tube tracker, calorimeter, veto

• how can we share infrastructure and do meaningful comparisons?

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Spectrometer Solenoid

• Does the COMET design lower backgrounds enough to use that design?

• late-arriving particles

• muons > 76 MeV/c: how many

• initial beam flash: what is propagated?

• electrons and neutrons

• What is the level of development of software used in calculating backgrounds?

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Tracker and Reconstruction• Straws in vacuum a common problem: much to

work on together

• Reconstruction algorithms: helical tracks in presence of noise hits

• Mu2e has sophisticated algorithm from MECO: is this helpful to COMET?

• investigating moving to Kalman filter

• Should both collaborations adopt same software framework? C++/ROOT/GEANT4/ and FNAL supported framework?

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Simulations

• How were these two plots made?

• What assumptions on energy loss in target?

• What resolutions were used?

• What reconstruction algorithms were employed?

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Calorimeter

• Both experiments have trackers with resolution ~0.1-0.2% -- what is the role of a calorimeter with at least x10 worse resolution?

• is it useful as a trigger?

• how does it help in suppressing misreconstructions?

• assuming utility, what is best technology?

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CR Veto

• Is one of COMET/Mu2e more or less sensitive?

• How have CR backgrounds been calculated?

• are we using common CR model?

• Are shielding requirements different?

• Is “new site” at FNAL more flexible than J-PARC hall for designing shielding?

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Extinction

• Given all the differences in solenoids, are extinction requirements the same?

• specifically, radiative pi capture?

• different arrival time distributions

• different beam structure

• But much room for collaboration on monitoring and AC-dipole

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Common Physics Issues• DIO: rate and spectrum

• can’t stand up and claim a modest signal if this disagrees

• need better calculations

• Neutron Production

• thermalization can produce 2.2 MeV γ and overwhelm veto?

• neutrons, KL producing electrons that get propagated?

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Measuring Resolution

• Must be able to predict observed DIO spectrum

• How do we measure resolution?

• How do we check energy loss?

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Conclusions

• Many areas where direct comparisons would be useful as

• a check

• determine best design

• Obviously significant overlap of physics issues where we could share work

• Have fun!

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Documents

Goals and Questions for Workshopmoller.physics.berkeley.edu/~yury/mu2e/talks/bernstein1.pdf · Goals and Questions for Workshop ... C++/ROOT/GEANT4/ ... ¥ canÕt stand up and claim