Performance simulations with a realistic model of the CBM Silicon Tracking System

rucksackbulgeΤεχνίτη Νοημοσύνη και Ρομποτική

1 Δεκ 2013 (πριν από 3 χρόνια και 8 μήνες)

64 εμφανίσεις

Performance simulations
with
a realistic model of the
CBM Silicon Tracking System

Silicon tracking
for

CBM

Number of
integration
components

Ladders

106

Sectors

1040

Sensors

1292

R/O chips

16640

Channels

2133k

Sectors

Sector

type

S1

S1
S

S2

S3

S3
C2

S3
C3

Used sensors

1

1

1

1

2

3

Physical length
[cm]

2.2

2.2

4.2

6.2

12.4

18.6

Physical width
[cm]

6.2

3.1

6.2

Number of
strips

1024

512

1024

Strip pitch

58µm

Simulation
&

Reconstruction

STS Layout

Results

References:

[1]

A.Kotynia, J.M.Heuser, W.Müller, „Simulation of realistic detector response in

the CBM Silicon Tracking System”, CBM Progress Report 2009 7

[2]

Nuc. Instr. Meth. A497 (2003) 389
-
396

[3]

I.Kisel, I.Kulakov, I.Vassiliev, „A standalone package for on
-
line event selection

in the CBM experiment”, CBM Progress Report 2008 79


Track category

Efficiency, %

Reference set (>1
GeV
/c)

95.2

All set (≥4 hits,>100
MeV
/c)

89.8

Ghost (made from fake hits)

6.6

Challenge
:



Au+Au collision
s ,
25 GeV/u



up to 1000 charged particles
/event



interaction rates up to 10 MHz

STS requirements
:


r
adiation hard and
low
-
mass
detector
system


h
igh position resolution


t
rack reconstruction for all charged
particles


m
omentum resolution of order 1.5%
at 1GeV/c


p
rimary

vertex resolution
of about

50µm


8
tracking stations:

30, 40, 50, 60, 70, 80, 90, 100 cm
downstream of target,

in 1 T dipole magnet;


4

m
2

active
area;


The number, position and
segmentation of the layers are
optimized for efficient track
reconstruction and high momentum
resolution.


Realistic STS system in
CbmRoot


The simulations include complete chain of physical processes
caussed by charged particletraversing the detector [1]
.


Hit Finding efficiency:

Primary

:

98.
97

%

Secondary

:

91.69 %


Point resolution
:


Vertical
:



60

µm

Horizontal
:


8
µm





In
300 µm thick
silicon
sensors

about

23
k

electron
-
hole pairs are
produced by minimum
-
ionizing particles.


The c
harge
is shared by one or more collecting strips.

Layout of the
8 STS
s
tation
s

Brea
k
down of STS components




STS in dipole magnet

Simulated track of a minimum ionizing
particle in the silicon detector

I
nfluence of a magnetic field on the
collection of charge on the strips [2]

Charge collected on the most significant strip in cluster;

different colors represent different cluster sizes

Hit resolution in STS obtained using
realistic detector model for vertical (green)
and horizontal direction (red)

Hit pull distribution in STS for vertical
direction (green) and horizontal (red)

Track reconstruction efficiency obtained using
cellular automaton track finder [3]

Signal peak height [a.u.~1ke
-
]

Hit resolution

Hit pull


The STS s
tations
have a modular structure and are constructed from
4
ty
p
es

of 300µ
m
thick double
-
sided silicon micro
-
strip sensors,
arranged on 8 types of carbon
-
fiber supported ladder structures.




Mechanical design of a carbon fiber support structure.


P
article position
obtain
ed with
Center
-
Of
-
Gravity
algorithm:







n
i
i
n
i
i
i
ADC
Ch
ADC
COG
1
1
Anna Kotynia

Goethe
University, Frankfurt,
Germany

for the CBM Collaboration


http://www
-
cbm.gsi.de