E313Spectrometer optimization

Maximiliano Sioli

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General considerations• We want to optimize the magnetic spectrometer with the

(financial?) constraint that it has to be a “Downstream Dipolar Magnet Spectrometer” (DDMS)

• The previous statement is necessary since for such an experiment the best would be a spectrometer à la UA1/NOMAD:

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DDMS for the near detector• Given the relatively low energy muon beam, we now focus on the

possibility to build a “compact” DDMS which uses a unique detector (e.g. RPC) interleaved with variable-thickness iron slabs.

• Method:– FLUKA simulation of the LAr target + down stream “infinite” iron block– Muon vertex and kinematics from Stefano simulation– Store all muon stopping points

• Result(top view):

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x (cm)

z (cm)

FeLAr

DDMS for the near detector• Statistics:

– Total number of muons: 14767– Muons stopping in LAr or Fe: 14360– Muons stopping in Fe: 8865– ... and with at least 10 cm penetration: 7457– ... and with |Dx|<8.7/2 m & |Dy|<5.7/2 m: 4657 (norm)

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44%

29%

27%

1 2

1° arm: 24 slabs 2.5 cm thick2° arm: 12 slabs 5 cm thick

Muon range

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5 x 7.87 / 0.106 = 374p ~ 180 MeVT ~ 100 MeVDT ~ 30 MeV

2.5 x 7.87 / 0.106 = 187p ~ 120 MeVT ~ 55 MeVDT ~ 15 MeV

Charge measurement

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Pm vs Zstop Em vs Zstop

All

Charge measurement

Method: bending angle

B = 1.5 T

B = 1.0 T

B = 0.5 Th

Iron thickness

Charge measurement

Method: sagitta

B = 1.5 T

B = 1.0 T

B = 0.5 Th

Iron thickness

1 cm resolutionfor 250 GeV/c muons(~10 cm) 1 cm resolution

for 750 GeV/c muons(~50 cm)

Charge measurement

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LAr