TT Alignment

A. Chukanov, Yu. Gornushkin,

S. Zemskova

LNGS, 27th of April 2007

Dubna’s group activity

• Muon track reconstruction (TT alignment, brick finding)

• TT alignment

• Measurement of TT efficiency

• Study of PMT pedestals stability

• TODO study of PMT signals stability (gains)

TT Alignment with the help of muon tracks

3D Muon track

Distances

Hits

distances

D vs Y

Main goal – minimization of all distances for all tracks

3 dimension transformation

• 3 angles – around X, Y and Z axises

• Shifting along Z-axis (beam line)

• Shifting along X-axis

• Non-linearity along strips

X

Y (strip)

Z (beam)

Hits corrections in module

• Reweghting of muon angle distribution

• Reweghting of X and Y muon hits distribution

XZ angle YZ angle

Rotation around beam line

dXa, cm

beam

Strips

Rotation around strip line

dZa, cm

beam

Strip

Shifting transverse to strips direction

dX, cm

beam

Strip

Strips non-linearity

h, cm

beam

Strip

Strips non-linearity dYv, cm

beam

Strip

Strips non-linearity

dZ, cm

beam

Strip

Iteration procedure

Conclusion

• Preliminary TT alignment has been made

• Relative parameters was obtained

• Cross-checks and tests are needed

• Absolute measurements are needed (bricks and TT position)

• Necessary to measure relative position of TT, DT and RPC