1

Stability of the TOF calibration and the effect on phase space reconstruction

MICE analysis meeting, 7th September 2010

Mark Rayner, University of Oxford

AMDG

LDS

Cooling channel Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9DK sol D2D1

TOF1TOF0Target

Diffuser TOF2

Update on beam characterization with the TOFs, and data analysis of recent runs 2

Calibrated time of flight, runs 1590 - 2896

time of flight (ns)

February calibration August calibration

Update on beam characterization with the TOFs, and data analysis of recent runs 3

Pixel coverage of the two calibrations

Update on beam characterization with the TOFs, and data analysis of recent runs 4

Dispersion leads to the fast muon depletion in August

February calibration

February calibration with TOF0 x < 99 mm

August calibration

Dispersive beam line:High pz muons have TOF0 x >= 100 mmNot yet included in the August calibration

Update on beam characterization with the TOFs, and data analysis of recent runs 5

Calibrated e+/e– peak, runs 1590 - 2896

February calibration August calibration

24.40 < t / ns < 26.40 24.45 < t / ns < 26.45

Update on beam characterization with the TOFs, and data analysis of recent runs 6

Mean calibrated e+/e– time of flight

February calibration

August calibration

Update on beam characterization with the TOFs, and data analysis of recent runs 7

RMS e+/e– time of flighty = mx + c Parameter Errorc 9.31e-02 1.085e-03m 9.31e-06 4.52e-07

y = mx + c Parameter Errorc 9.19e-02 1.06e-03m 8.29e-06 4.39e-07

February calibration

August calibration

Update on beam characterization with the TOFs, and data analysis of recent runs 8

February/August comparison

February calibration

August calibrationPositrons

(shaded squares)

Electrons(open squares)

Update on beam characterization with the TOFs, and data analysis of recent runs 9

Runs with Q7,8,9 off

February calibration August calibration

24.40 < t / ns < 26.40 24.45 < t / ns < 26.45

Update on beam characterization with the TOFs, and data analysis of recent runs 10

Conclusion• Bias on p given by bias on time of flight and path length

– Possible calibration drift of order 0.05 ns * c = 15 mm– G4Beamline simulation of positron path length = 4 mm + z

• Can we explain the positron time of flight width?– (TOF resolution of 70 ps)2 + (MC path length width of 10 ps)2 != (Observed 100 ps)2

• 0.5 ns shift in muon peak 12% momentum shift at 250 MeV/c

G4Beamline simulation of TOF positron

calibration runs 1590 - 1591