MuScat: plans and results

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MuScat plans and results

• Birmingham University
• BNL
• BBC
• CERN
• GIRAG
• Imperial College
• Jefferson Lab

Oxford University RIKEN Rutherford Appleton
Laboratory Tohoku University TRIUMF University
California - LA
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Status of MuScat (E875)

• Reminder motivation
• MuScat in 2000
• Targets
• Results
• MuScat in 2003
• Liquid Hydrogen target
• Scintillating Fibre trackers
• Conclusions

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Multiple Scattering Data

• No relevant data
• Most relevant electron scattering in 1942!

Li
Be
Al
Moliere theory
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Scattering Theory

• Sufficient uncertainty
• Good way to get started ? Should be
  measured

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MuScat - 2000
Collimator
Targets
MINA - NaI
DLCs
Expansion volume
Shield
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MuScat - 2000
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Targets used in 2000

• Solid targets mounted on a rotating wheel
• Lithium x2
• Beryllium x2
• Aluminium All around 1 X0
• Carbon
• Polythene
• Iron
• LH2 - Was not included in engineering run
  Always planned for a second run

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How did it go?

• What went well?
• Hardware installation, alignment
• Data taking, beam
• Particle ID
• Position/angle resolution
• Simulation/data agreement
• What went badly?
• Preparation of Li2 samples
• Tails in distributions - high p?
• Tracking Chamber systematic errors

Engineering Run
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Particle ID

• TOF from S1 w.r.t beam cycle
• Cross-checked with calorimeter
• p contamination in ms
• small
• measurable

Very nice
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Chamber Efficiency

• DLC Chamber efficiency not flat
• Outside 10cm may be calibration?
• Centre distorted
• No perfect calibration found
• Time dependent

Not so nice
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Vacuum Distributions

• Simulation matches data reasonably
• Secondary sources are modelled

3cm
Not Even Preliminary
10cm
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What was changed for Run II?

• New beamline
• Liquid Hydrogen target
• The most important target (correct, Z1)
• Required improved vacuum specs.
• New Chambers
• Scintillating Fibre detectors
• Accurate, more efficient
• Improved Collimator system
• New active collimation
• Tuning of passive collimator positions

Final Run
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M20 Beamline
M20
M11
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New Beamline

• M11
• Pion beamline
• High momentum (450 MeV/c)
• Narrow momentum bite (1)
• Big background
• M20
• Quadrupole decay channel
• Mainly surface muons
• Forward muon decays 175 MeV/c
• Not used for 20 years!

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New Beamline
M11
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MuScat Version 2
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Liquid Hydrogen Target

• Target volume made by TRIUMF group
• Operated with liquid and empty separately to
  measure effect of walls
• Two thicknesses of liquid Hydrogen used 10
  15cm
• Improved vacuum required
• New vessel used
• Safety approval and operation walk in the park!

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New Vessel
5 x 10-6 Torr!
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Improved Collimation system

• In 2000, tails from
• Penetration of second collimator
• Secondary sources, particularly intermediate
  disks
• In 2003
• Intermediate disks moved to ends
• New disks, bigger aperture, active collimator
• Additional lead and steel

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Scintillating Fibre Tracker

• 3 detectors, each 340mm square
• x and y readout, 2 offset planes of 1mm fibres
  in each
• 512 fibres/plane
• 0.66mm pitch
• in vacuum
• L16 PMTs
• sample/hold
• worked well!

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Sci-Fi tracker

• 512 fibres/orientation/plane, 3 planes
• ? 3072 channels
• Multiplex 256 fibres into 16 channel PMTs.
• R/O both ends of fibre, in 16 groups of 16
• 1 end for group, other for fibre number
• 24 PMTs to read all channels
• Multiplexing flags multi-hit events

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Data-taking in 2003

• Setting up with beam started 25th April
• Real data-taking with LH2 started 28th April
• Finished 6th May 12M events with/without targets
• Data taking with solid targets started 7th May
• Finished 13th May Thick Li -
  6M Thin Li - 6M Thick Be -
  3M Thin Be - 3M Al - 3M C -
  2M Polythene - 2M Thick Fe -
  2M Thin Fe - 2M Empty - 5M

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Results.

• TOF

• Beam momentum

• TINA

• Scattering..

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Results.
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Empty
Thin Li
Thick li
Thick Fe
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Conclusions

• MuScat engineering in 2000 run went well
• Some lessons learned
• Used for an improved version
• 2003 Physics run all went very well
• 46M events taken
• LH2 as well as solid targets
• First look at data very good
• Analysis just starting
• First results ENG meeting 9th July
• Final results by end of year