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Chris Rogers

MICE VC, 15th Dec 2004

MICE Simulation Meeting 19th Jan 05

Verification of Tracking in G4MICE

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Position - comparison with ICOOL

• Downstream x against upstream px

• Absolute value goes linearly, as we would expect• Difference between ICOOL and G4MICE also linear up to px(z = -5711) = 30 MeV

<x> = [x(ICOOL) + x(G4MICE)]/2 at z = 5711dx = [x(G4MICE) - x(ICOOL)] at z = 5711

1 mm step sizeInitially, x = (0,0,-5711); p = (px, 0, 200)Initial px plotted on y-axis

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Position - comparison with ICOOL (redux)

• Downstream x against upstream px

• Absolute value goes linearly, as we would expect• Difference between ICOOL and G4MICE also linear up to px(z = -5711) = 30 MeV

<x> = [x(ICOOL) + x(G4MICE)]/2 at z = 5711dx = [x(G4MICE) - x(ICOOL)] at z = 5711

1 mm step sizeInitially, x = (0,0,-5711); p = (px, 0, 200)Initial px plotted on y-axis

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Position - along z

• Again we have mean x-position and x between ICOOL and G4MICE• Note these are the absolute values• Initial px = 30 MeV (left), 100 MeV (right)• where particle crosses axis, relative difference • “Typical” difference ~1% - 10% (grows along channel)• Implications for emittance? - significant

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Position - along z (redux)

• Again we have mean x-position and x between ICOOL and G4MICE• Note these are the absolute values• Initial px = 30 MeV (left), 100 MeV (right)• where particle crosses axis, relative difference • “Typical” difference ~0.1% at downstream end of the channel• Implications for emittance? - significant

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Momentum - comparison with ICOOL

• Downstream px against upstream px

• Absolute value again looks quite linear• Difference between ICOOL and G4MICE also linear up to px (z = -5711) = 30 MeV

<px> = [px(ICOOL) + px(G4MICE)]/ 2 at z = 5711dpx = [px(G4MICE) - px(ICOOL)] at z = 5711

1 mm step sizeInitially, x = (0,0,-5711); p = (px, 0, 200)px plotted on y-axis

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Momentum - comparison with ICOOL (redux)

• Downstream px against upstream px

• Absolute value again looks quite linear• Difference between ICOOL and G4MICE also linear up to px (z = -5711) = 30 MeV

<px> = [px(ICOOL) + px(G4MICE)]/ 2 at z = 5711dpx = [px(G4MICE) - px(ICOOL)] at z = 5711

1 mm step sizeInitially, x = (0,0,-5711); p = (px, 0, 200)px plotted on y-axis

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Momentum - along z

• Here we have mean x-position and x between ICOOL and G4MICE

• Again relative difference when the muon crosses the axis

• “Typical” difference ~ 1% at 30 MeV, 10% at 100 MeV

• High transverse momentum particles are of interest for physics analysis

• Should seek to understand the discrepancy

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Momentum - along z (redux)

• Here we have mean x-position and x between ICOOL and G4MICE

• Again relative difference when the muon crosses the axis

• “Typical” difference ~ 0.1%

• High transverse momentum particles are of interest for physics analysis

• Should seek to understand the discrepancy

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Emittance Performance - magnets only (1 mm)

ICOOLG4MICE

• Systematic difference ~ 0.2 %• Not yet good enough; we would like this to be << 0.1 %• 1 mm step size = processor heavy

1 mm step size, ~ 1000 events

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Emittance Offset - a bug in ecalc9?

• G4MICE emittance plots come out offset from ecalc9 plots by a small amount.– Calculate emittance in ecalc9 for some small set of

particles– Calculate emittance in G4MICE for the same set of

particles– They are different

• Take out the reference particle and the first event from the G4MICE calculation then the emittance is the same in ecalc9 and G4MICE– I think this has to be a bug in ecalc9

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Proposed Fixes/Improvements

• Fix B-field interpolation algorithm plot– Plot decent contours

• Use the same field map

• Check emittance offset

• Fix/improve VirtualPlanes interpolation algorithm

• Plot error(step size)

• Absorbers/RF/Cooling plots