muon simulations
DESCRIPTION
Muon simulations. Anna Kiseleva. Outline. Muon simulations for different collision systems: SIS 300 SIS 100 Muon system optimizations: material of pipe shielding thickness of first absorber alternative solutions of muon system Additional electrons from absorber: - PowerPoint PPT PresentationTRANSCRIPT
16 October 2008 1 12th CBM Collaboration meeting Oct. 13-18 2008, JINR Dubna
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Muon simulations
Anna Kiseleva
16 October 2008 12th CBM Collaboration meeting Oct.
13-18 2008, JINR Dubna
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Outline• Muon simulations for different collision systems:
• SIS 300
• SIS 100
• Muon system optimizations:• material of pipe shielding
• thickness of first absorber
• alternative solutions of muon system
• Additional electrons from absorber:• comparison of different simulation tools
• enhanced "noise" from secondary electrons
• Conclusions• Next steps
16 October 2008 12th CBM Collaboration meeting Oct.
13-18 2008, JINR Dubna
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Simulations• cbmroot release v.APR08• signals: multiplicities from HSD, Pluto generator
• ω, J/ψ
• background: UrQMD central events• Au+Au at 15, 25 and 35 AGeV
• Au+Au at 8 AGeV
• p+C at 30 GeV
• muon magnet• standard STS• standard MuCh• MuCh hit producer without clusters• L1 (STS) and L1/Lit (MuCh) tracking
16 October 2008 12th CBM Collaboration meeting Oct.
13-18 2008, JINR Dubna
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C B MStandard Muon Chambers (MuCh) system
low-mass vector meson measurements(compact setup)
≡ 7.5 λI ≡ 13.5 λI
Fe
20 20 2
0 30
35 1
00 cm
shielding
5%occupancyfor central
Au+Au collisionsat 25 AGeV
w/o shielding
Total number
of channels:
480768
min pad 1.42.8 mm2
max pad 44.844.8 mm2
16 October 2008 12th CBM Collaboration meeting Oct.
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C B MAu+Au at 25 AGeV*
Signal-to- Efficiency Mass
Background (%) resolution
(S/B) ratio (MeV)
ω 0.09 2 10
φ 0.03 4 12
J/ψ 18 13 21
Ψ' 0.8 16 27
signals
J/ψ
Ψ'
background
signals
ρ
ω
φ
η
ηDalitz
background
* 10th CBM Collaboration Meeting
16 October 2008 12th CBM Collaboration meeting Oct.
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Lit tracking Andrey Lebedev "Track reconstruction in MUCH"
Standard MuCh: 6 Fe absorbers (225 cm)
18 detector stations
Compact MuCh: 5 Fe absorbers (125 cm)
10 detector stations
Events: URQMD central Au+Au at 25 AGeV
+5 mu+ and 5 mu- in each event
(p=1.5..10 GeV/c for compact and p=2.5..25 GeV/c for standard)
Compact Standard
all 96.2% 97.5%
ref 97.1% 97.6%
prim 96.4% 97.5%
sec 89.2% 89.0%
muons 96.8% 97.5%
ghost 1.5% 0.21%
clone 0.0% 0.0%
16 October 2008 12th CBM Collaboration meeting Oct.
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Tracking proceduresReconstructed background:
L1 Lit
L1 Lit
S/B 0.091 0.095
ε, % 1.7 1.9
Andrey Lebedev "Track reconstruction in MUCH"
ω→μ+μ- + central Au+Au collisions at 25 AGeV
16 October 2008 8 12th CBM Collaboration meeting Oct. 13-18 2008, JINR Dubna
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SIS 100
Au+Au at 8 AGeV
p+C at 30 GeV
16 October 2008 12th CBM Collaboration meeting Oct.
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Compact muon system
Au+Au at 8 AGeV
min. 9 hits tracks min. 12 hits tracks
Pluto
ω in Au+Au collisions at 8 AGeV
16 October 2008 12th CBM Collaboration meeting Oct.
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Results of L1 reconstruction
ω
min. 9 hits min. 12 hits
S/B 0.05* 0.1*
ε, % 1.65 0.95
Au+Au at 8 AGeV
* we can improve results, if we will have ToF pID in MuCh and/or make some simple modifications of CBM setup (see backup slides)
16 October 2008 12th CBM Collaboration meeting Oct.
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J/ψ + central p+C collisionsω + central p+C collisions
1 ω→μ+μ- in 105 central events 4 J/ψ→μ+μ- in 109 central events
Results of L1 reconstruction
p+C at 30 GeV
ω J/ψ
S/B 11 147
ε, % 4.3 22.7
comparison of HSD and Pluto generated J/psi - see backup slides
16 October 2008 12 12th CBM Collaboration meeting Oct. 13-18 2008, JINR Dubna
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Muon system optimization
16 October 2008 12th CBM Collaboration meeting Oct.
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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 absorber
16 October 2008 12th CBM Collaboration meeting Oct.
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with pipeshielding
with pipeshielding
Motivation: decrease hit density in first detector layers
16 October 2008 12th CBM Collaboration meeting Oct.
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Particle absorption
central Au+Au collisions at 25 AGeV
16 October 2008 12th CBM Collaboration meeting Oct.
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C B MThickness of first absorber (Fe)
10 cm 100 cm
10 cm Fe
20 cm Fe
30 cm Fe
40 cm Fe
central Au+Au collisions at 25 AGeV
ω→μ+μ- + central Au+Au collisions at 25 AGeV
≥4STS+3MuCh
4
ghosts !
16 October 2008 12th CBM Collaboration meeting Oct.
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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 10 cm Fe
20 cm Fe
30 cm Fe
40 cm Fe
16 October 2008 12th CBM Collaboration meeting Oct.
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MuCh 25 30 40 40
25 30 40
40
Nchannels 439 296 → 272 384
16 October 2008 12th CBM Collaboration meeting Oct.
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Comparison
ω→μ+μ- + central Au+Au collisions at 25 AGeV
MuCh
20 20 20 30 35
MuCh
25 30 40 40
S/B 0.095 0.094
ε, % 1.9 1.8
― MuCh 20 20 20 30 35
― MuCh 25 30 40 40
16 October 2008 21 12th CBM Collaboration meeting Oct. 13-18 2008, JINR Dubna
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Additional electrons from absorber
16 October 2008 12th CBM Collaboration meeting Oct.
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C B MParticle rate in first MuCh detector
TGEANT3: hadronic processTGEANT4: QGSP_BERT_EMVTFluka
16 October 2008 12th CBM Collaboration meeting Oct.
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C B MParticle statistics (per event): 20 cm Fe
particles: GEANT3 GEANT4 Fluka
all 836 1001 1141
primary 106 105 105
secondary: 730 896 1037
e 521 607 705
p 91 121 139
π 98 159 174
central Au+Au collisions at 25 AGeV
16 October 2008 12th CBM Collaboration meeting Oct.
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particles: GEANT3 GEANT4 Fluka
all 100 % + 23 % + 42 %
primary 100 % + 16.5 % + 33.8 %
secondary: 100 % + 33 % + 52.8 %
e 100 % + 62 % + 77.6 %
p 100 % + 23 % + 42 %
π 100 % + 16.5 % + 33.8 %
Particle statistics (per event): 20 cm Fe central Au+Au collisions
at 25 AGeV
16 October 2008 12th CBM Collaboration meeting Oct.
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C B MMomentum distributions (20 cm Fe)
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Problems• TFluka is unstable in cbmroot
• Present setup of TGEANT4 doesn't include muon production in thick material
• Is production of secondary particles in absorber material correctly described?
16 October 2008 12th CBM Collaboration meeting Oct.
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C B MModeling additional electron hits
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
16 October 2008 12th CBM Collaboration meeting Oct.
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Statistics (per event)
standard 1e 2e 3e 4e 5e 10e
MC points
2991
hits 2910 4161 5411 6660 7909 9158 15408
central Au+Au collisions at 25 AGeV
?
16 October 2008 12th CBM Collaboration meeting Oct.
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Horizontal hit distribution
MC points
― standard hitsadditional e:
― +1
― +2
― +5
― +10
central Au+Au collisions at 25 AGeV
16 October 2008 12th CBM Collaboration meeting Oct.
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Invariant mass spectraω→μ+μ- + central Au+Au collisions at 25 AGeV
16 October 2008 12th CBM Collaboration meeting Oct.
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Results of Lit reconstruction
standard hits
1e 2e 3e
S/B 0.095 0.090 0.11 0.076
ε, % 1.92 1.58 1.575 1.4
ω→μ+μ- + central Au+Au collisions at 25 AGeV
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Background
+1e +2e +3e
central Au+Au collisions at 25 AGeV
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Conclusions• Simulation tools have been developed to design and
optimize CBM muon detection system.
• The present muon detector design is tested for different collision systems and beam energies (incl. SIS100).
• Simulations with enhanced yield of secondary electrons have been started. Track reconstruction efficiency decrease slightly with increasing number of secondary electrons up to a factor of 3 which corresponds to an increase of total hit density by more than a factor of 2. Simulations with higher hit densities are in progress.
16 October 2008 12th CBM Collaboration meeting Oct.
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Next steps• Implementation of:
• realistic detector description • 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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Thank you for your attention!
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Backup slides
16 October 2008 12th CBM Collaboration meeting Oct.
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ToF(80 ps)
Muon system with ToFm2 =
β =
γ =
m2 = P2 ( - 1)
Lc × t
√1 – β2
1
(β × γ)2
P2
β2
1
Au+Au at 8 AGeV
16 October 2008 12th CBM Collaboration meeting Oct.
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m2 vs. Preco
signal μ background
9 hits
12 hits
15 hits
9, 12 and 15 hits tracks
16 October 2008 12th CBM Collaboration meeting Oct.
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Results after ToF pID
ω
min. 9 hits min. 12 hits
S/B 0.05→0.09 0.1→0.14
ε, % 1.65→1.2 0.95→0.8
Au+Au at 8 AGeV
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Possible modifications for increasing of signal
acceptance
Au+Au at 8 AGeV
16 October 2008 12th CBM Collaboration meeting Oct.
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1. Decreasing magnet fieldmagnet field: 100% 50% magnet field: 100% 50%
+ 12% μω
+ 22% ω
Au+Au at 8 AGeV
16 October 2008 12th CBM Collaboration meeting Oct.
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C B M2. Decreasing the thickness of the absorbers
Au+Au at 8 AGeV
16 October 2008 12th CBM Collaboration meeting Oct.
13-18 2008, JINR Dubna
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C B MJ/ψ in p+C @ 30 GeV: Pluto and HSD
HSD Pluto
Pluto
HSD
p+C at 30 GeV
16 October 2008 12th CBM Collaboration meeting Oct.
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Results of L1 reconstruction
Pluto HSD
S/B 147 115
ε, % 22.7 13.3
p+C at 30 GeV
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Reconstructed J/ψ
Pluto
HSD
p+C at 30 GeV
16 October 2008 12th CBM Collaboration meeting Oct.
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C B MComparison of ideal with realistic detector resolution
beam energies
15AGeV 25AGeV 35AGeV
S/B 0.08 0.07 0.07
ε, % 2.4 3.6 4.7
beam energy
── 15 AGeV
── 25 AGeV
── 35 AGeV
σ =100 μm
Lit
S/B 0.095
ε, % 1.9
ω→μ+μ- + central Au+Au collisions
segmentation