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Status of muon simulationsAnna Kiseleva

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Outline• Standard muon system

• evolution• present version

• Muon simulations• background study• time measurements• results for different collision systems

• Muon system optimizations• clustering• detector inefficiency• material of pipe shielding• absorber study• possible modifications of muon system• e noise: first results

• Important future steps

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Muon system

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Muon system evolution

2004 2005

2006 2007 2008

1. ~90% of π and ~50% of K decay to μ2. one needs to determined precisely (~1º) kink angle

S/B ratio is too bad. One needs to have morethen 1 detector layer between absorbers

One needs to have more compact system as possible

One needs to optimize systemfor different options (LMVM & charm)

Additional pipe shieldingis needed

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Standard Muon Chambers (MuCh) system

low-mass vector meson measurements(compact setup)

≡ 7.5 λI ≡ 13.5 λI

Fe20 20 2

0 30

35 1

00 cm

shielding

5%occupancyfor central

Au+Au collisionsat 25 AGeV

w/o shielding

Total number

of channels:

480 768

min pad 1.42.8 mm2

max pad 44.844.8 mm2

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Muon simulations

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Tracking procedures

For p and K suppressions we need one more pID measurement L1 Lit

S/B 0.091 0.095

ε, % 1.7 1.9

Reconstructed background:

L1 Lit

ω + central Au+Au collisions at 25 AGeV

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ToFtime resolution 80 ps

m2 =

β =

γ =

m2 = P2 ( - 1)

Lc × t

√1 – β2

1

(β × γ)2

P2

β2

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Time measurements in MuChω + central Au+Au collisions at 25 AGeV

signal μ background

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Results

with ToF

S/B 0.1 0.2

εω % 2.1 1.6

with ToF

ω + central Au+Au collisions at 25 AGeV

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Results for different collision systems

central Au+Au

@ 25 AGeV

central Au+Au

@ 8 AGeV

central p+C

@ 30 GeV

ωToF pID J/ψ ωToF pID J/ψ ω J/ψ

S/B 0.17 18 0.14 (0.09)* – 11 147

ε, % 1.5 13 0.8 (1.2)* – 4 23

* in order to increase the acceptanceof reconstructed ω we can use different type of tracks

SIS 300 SIS 100 see talk 16.10

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Muon system optimizations

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Clusters + Avalanches (C&A)primary electrons

sec. electron

s

w/o C&A with C&A

S/B 0.1 0.1

ε, % 2.1 1.3

ω + central Au+Au collisions at 25 AGeV

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minimum 9 hits required minimum 14 hits required

Track reconstruction with reduced detector efficiency

ω→μ+μ- + central Au+Au collisions at 25 AGeV

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Material of pipe shieldingpa

rtic

les/

(eve

nt×

cm2)

part

icle

s/(e

vent

×cm

2)

1 2 3

4 5― Fe

― W

― Pb + Fe

central Au+Au collisions at 25 AGeV

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Thickness of first Fe

10 cm 100 cm

ω→μ+μ- + central Au+Au collisions at 25 AGeV

10 cm Fe

20 cm Fe

30 cm Fe

40 cm Fe

central Au+Au collisions at 25 AGeV

ω

see talk 16.10

central Au+Au collisions at 25 AGeV

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Alternative muon systems

40 20 20 20 25

30 20 20 20 35

20 20 20 30 35

10 20 30 30 35

central Au+Au collisions at 25 AGeV

see talk 16.10

10 cm Fe

20 cm Fe

30 cm Fe

40 cm Fe

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MuCh 25 30 40 40

25 30

40 40

Nchannels 439 296 → 272 384min pad size (mm2):1.4×2.8

2.8×2.8

2.8×5.6

5.6×5.6

see talk 16.10

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Comparison with standardω + central Au+Au collisions at 25 AGeV

standard compact MuCh

MuCh

25 30 40 40

S/B 0.095 0.094

ε, % 1.9 1.8

― standard compact MuCh

― MuCh 25 30 40 40

see talk 16.10

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Electron noise

e

1. Create true hit (X0, Y0)

2. If e, create new point (X0+∆X, Y0+∆Y)

3. Create noise hit (Xnoise, Ynoise)

4. Possibility to create more then 1 noise hit from 1 true e

see talk 16.10

central Au+Au collisions at 25 AGeV

standard 1e 2e 3e 4e 5e 10e

MC points

2991

hits 2910 4161 5411 6660 7909 9158 15408

MC points

― standard hitsadditional e:

― +1

― +2

― +5

― +10

?

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Reconstruction with e-noiseω + central Au+Au collisions at 25 AGeV

standard hits

1e 2e 3e

S/B 0.095 0.090 0.11 0.076

ε, % 1.92 1.58 1.575 1.4

see talk 16.10

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Summary• Simulation tools have been developed to design and optimize

CBM muon detection system.

• Present muon detector design is tested for different collision systems, and is able to measure muons already at SIS100.

• Simulations with additional electron noise show the possibility to separate reconstructed signal and background even when increasing 3 times the number of secondary electrons, which corresponds to increasing of hit density more than 2 times.

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Next steps• Implementation of:

• realistic detector discription • different type of the detectors

• inefficiency of the detectors

• muon trigger

• additional secondary electrons with correlated hits in detectors

• Muon system optimizations:• number of sensitive layers

• thickness of absorbers

• optimization tacking into account costs

• Test of possible solutions of muon system using LMVM and charmonium simulations

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• Implementation of flexible Hit Producer

• possibility to change the structure of detector layer

• possibility to change thesize of detectors only inregion of interest

• size of detectors in X and Y directions are independent

Wish list

now

wishnow

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Thank you for your attention!