status of muon simulations

1

Status of muon simulationsAnna Kiseleva

2

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

3

Muon system

4

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

5

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

6

Muon simulations

7

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

8

ToFtime resolution 80 ps

m2 =

β =

γ =

m2 = P2 ( - 1)

Lc × t

√1 – β2

1

(β × γ)2

P2

β2

1

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

signal μ background

9

Results

with ToF

S/B 0.1 0.2

εω % 2.1 1.6

with ToF

ω + central Au+Au collisions at 25 AGeV

10

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

11

Muon system optimizations

12

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

13

minimum 9 hits required minimum 14 hits required

Track reconstruction with reduced detector efficiency

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

14

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

15

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

4

16

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

17

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

18

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

19

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

?

20

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

21

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.

22

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

23

• 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

24

Thank you for your attention!