Post on 03-Jan-2016
description
transcript
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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!