1 j.m. heuser − silicon detector systems for cbm silicon detector systems for cbm johann m....
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J.M. Heuser − Silicon detector systems for CBM 1
Silicon detector systems for CBMSilicon detector systems for CBM
Johann M. Heuser, GSI CBM meeting, University of Jammu, 14 February 2008
Silicon Tracking System
Micro Vertex Detector
Silicon Tracking Layer in MUCH ?
Overview ofTasks & environments
Detector technologies
System concepts
Technical challenges & prototyping
J.M. Heuser − Silicon detector systems for CBM 2
CBM – Electron-Hadron setupCBM – Electron-Hadron setup
RICH
TRDs ECALTOF
target
beam
PSDSTS +
MVD
J.M. Heuser − Silicon detector systems for CBM 3
MVD +
STS
MUCH
TRD TOF
target
beam
PSD
CBM – Muon setupCBM – Muon setup
J.M. Heuser − Silicon detector systems for CBM 4
Tracking of up to ~700 charged particles per event
Momentum determination with ~ 1% resolution
Interaction rate up to 10 MHz
Online r/o & reconstruction
Unprecedented challenge in this combination. New innovative system concept & technologies !
UrQMD,Au+Au, 25 AGeV
SSilicon T Tracking S System
Low-mass large-area, fast, Low-mass large-area, fast, radiation-hard detector system radiation-hard detector system
Task & EnvironmentTask & Environment
J.M. Heuser − Silicon detector systems for CBM 5
SSilicon TTracking SSystem
1 T dipole magnet1 m8 tracking stations
microstrip detectors: thin, passive, high spatial resolution
double-sided detectors (default)single-sided detectors in 16 stations: under study
J.M. Heuser − Silicon detector systems for CBM 6
amplifiers in r/o chip: pulse height pattern
Silicon Microstrip DetectorsSilicon Microstrip Detectors
Variety of constructions:
single-sideddouble-sided DC-coupled r/oAC-coupled r/ostrip lengths up to ~10 cm ...
n-
n+
p+
+ bias
("diode in reverse direction of operation")
MIP in Si: ~ 80 e-h pairs per µm track
charged particle
typically 300 µm
typically 50-100 µm h
e-
signal ~ 24k e-
++
-
-
Al
J.M. Heuser − Silicon detector systems for CBM 7
Detector ConceptDetector Concept
Layout of the tracking stations "sectorization"
sector = certain number of sensors read out together
Building block ("module")
Performance evaluation
Iterations of the layout
Implementation of realistic sensors, support, material, backed up by detector R&D
station 1, z=20 cmstation 8, z=100 cm
module
sector, made from 3 detectors
~ 1 m2
J.M. Heuser − Silicon detector systems for CBM 8
Detector OccupancyDetector Occupancy
microstrip detectors, 60 µm strip pitch, 7.5o angle front-back
fraction of fired strips per detector
J.M. Heuser − Silicon detector systems for CBM 9
2 projective coordinates in one thin silicon layer ( double-sided strip detectors)
readout electronics outside tracking aperture
ladder construction: electrical contacts at sensor's top/bottom edge
no "dead" region in the detector corners, (despite of stereo angle front/back strips)
radiation tolerance: design, material
Technical challenge: Technical challenge: Microstrip detectorsMicrostrip detectors CBM STS
tracking station
Detector module
readout direction
p side (front):"stereo" strips
blue: double metal connect-ions of strips I to III
n side (back): "vertical" strips"vertical" strips
I II
III
CBM01: R&D study GSI-CIS with focus on
Double-sided micro-strip detector, connectible at top and bottom row.
J.M. Heuser − Silicon detector systems for CBM 10
Microstrip detector Microstrip detector prototype, GSI-CIS, 8/2007prototype, GSI-CIS, 8/2007
4" wafer CBM01, 285 µm Si Test sensors
Double-sided, double-metal, 1024 strips per side, 50.7 µm pitch, 15º stereo angle, full-area sensitive, contacts at top + bottom edge, size: 5656 mm2
Double-sided, single-metal, 256256 strips, orthogonal, 50(80) µm pitch, size: 1414 (22 22) mm2
Main sensor
Punch-through
biasing.
Polished float-zone Si.
I-V tests: Work as expected.
Addresses connectivity
Next iteration: radiation tolerance
Test board
J.M. Heuser − Silicon detector systems for CBM 11
Typical operation: about 6 years .
Situation:Interaction rate: 107/s Effective CBM run year:
2 months at full operation 5 × 106 s
Approaches:- Fluences estimated with URQMD generated events
- Fluence study with a FLUKA simulation of the CBM detector in its cave is ongoing
Estimated tolerance: ~ 1015 1-MeV neq
Challenge: Radiation EnvironmentChallenge: Radiation Environment
CBM cave
beam
STSdump
detector edge hit/cm2 part/cm2/6yr dose/6yr
STS @ 30cm inner 10 7.5·1014 20 Mradouter 0.25 1.8·1013 0.5 Mrad
STS @ 1m inner 1 7.5·1013 2 Mradouter 0.03 2.3·1012 60 krad
1 CBM-year assumed as: 2 month at 100% duty cycle 4 month at 50% duty cycle
J.M. Heuser − Silicon detector systems for CBM 12
Challenge: Combinatorial hitsChallenge: Combinatorial hits
microstrip detectors hybrid pixel detectors
1 central Au+Au event at 25 GeV/nucleon, tracking station at z=30 cm
compared with
track points : rec. points > 1:15 track points : rec. points 1:1
comb.hits
thin thick
true hits
Y [c
m]
X [cm]
J.M. Heuser − Silicon detector systems for CBM 13
Challenge: Tracking in STSChallenge: Tracking in STSCentral collisions Au+Au @ 25 AGeV
~ 1000 charged particles/event
~ 700 in aperture 2.5 – 25 deg
up to ~ 30 tracks/cm2 at z = 30 cm
required momentum resolution ~ 1%
effic
ienc
y [%
]
momentum [GeV/c]
Performance study of an 8-station STS:
Momentum resolution:
Track reconstruction efficiency:
includes cables, support(p > 1 GeV/c)
tracks [%]
primary, p > 1GeV/c 98.5
all, p>1 GeV/c 96.1
all, p> 0.1 GeV/c 90.4
3.2 % "ghost tracks"
Reconstructed central UrQMD event
XY
78 ms on Pentium 4 processor
XZ
"Cellular Automaton + Kalman Filter"
combinatorial hits
90 %
J.M. Heuser − Silicon detector systems for CBM 14
silicon sensorssilicon sensors + mech. frame
Momentum resolutionMomentum resolutionSTS with 8 microstrip tracking stations
400 µm Si per station
400 µm Si + 2 mm C ladder
400 µm Si + 2 mm C ladder + 2 mm Kapton
silicon sensors + mech. frame + r/o cables
[%]
J.M. Heuser − Silicon detector systems for CBM 15
material budget
Al-Kapton cables:
very thin (<50 µm total)
long high-density strip lines
50 µm pitch
low capacity (goal: S/N >10)
high-density interconnections
microstrip system
~20
- 60
cm
% X0
0.3
~1
.
.
.
.
>>1
r/o electronics
r/o electronics
Technical challenge: low-mass detector moduleTechnical challenge: low-mass detector module
1024 lines of 50 µm pitch: Cable length limited. to <10 cm.
1024 lines of 100 µm pitch: Two-layer cable → 50 µm eff. pitch. Length up to ~50 cm seem possible.
J.M. Heuser − Silicon detector systems for CBM 16
Pre-prototype of ultra-low-mass readout cable Pre-prototype of ultra-low-mass readout cable Cooperation with SESRTIIE Kharkov, Ukraine.
Structure: 55 cm length, 1024 lines, 100 µm line pitch
Material: 14 µm Aluminum on 10 µm Kapton
very challenging component
very challenging component
J.M. Heuser − Silicon detector systems for CBM 17
Challenge: Fast front-end electronicsChallenge: Fast front-end electronics High interaction rates: Require a data driven front-end.
n-XYTER chip 128 channels50.7 µm pitch
• dual polarity
• 30 ns peaking time
• ~1.4 ns jitter
• thresholds: > 2700 e
• count rates: ~160 kHz/strip
• token ring r/o scheme
• power: ~ 13 mW/ch
• 0.35 m CMOS
Used for CBM detector R&D: n-XYTER r/o hybrid for STS strip sensors.
Compatible with CBM DAQ board prototypes.
Lab and beam tests of STS.
Future:
Development of a new chip:
CBM-XYTER.
n-XYTER chip of the DETNI Consortium: Matches well CBM specs. Produced together with GSI.
J.M. Heuser − Silicon detector systems for CBM 18
Technical challenge: Technical challenge: Front-End Board & interconnectionsFront-End Board & interconnections
Future CBM-XYTER chip
detector/ readout cable
1024 channels per detector: 8128-ch readout chips
to ROC
FEB
r/o cable
sensor
~60 µm line pitch
Wire-bonding, tap-bonding of the thin fine-pitch structures?
~7 cm
FEB floor plan: how to arrange 8 chips in close distance?
50.7 µm
J.M. Heuser − Silicon detector systems for CBM 19
Challenge: System integrationChallenge: System integrationDetector module:
Electrical interconnections sensor-cable-FEE
Mechanical assembly of
- thin sensors + cables + front-end board
- on mechanical support frame.
Assembly steps single vs. double-sided module
Grounding/shielding
HV supply to sensors: through r/o cable, or extra cable?
Tracking system:MechanicsCooling of the fiducial volume? Insulation from hot FEE boards?
sensor
cable
FEE
J.M. Heuser − Silicon detector systems for CBM 20
MMicro VVertex DDetector
1 T dipole magnet1 m
2 vertexing stations
ultra-thin pixel detectors, very high spatial resolution
very low-mass mechanical support + thermal management
operated at sub-zero C temperatures in vacuum
Pioneering a fully novel, world-record thin detector system technique based on CMOS monolithic pixel sensors on diamond supports
J.M. Heuser − Silicon detector systems for CBM 21
Add-on to tracking: Precision decay vertex identification (D, c), spatial resolution few tens µm
Operational with at least 100 kHz interaction rate
Online charm trigger
New innovative system concept & technologies !
UrQMD,Au+Au, 25 AGeV
MVD - Task & EnvironmentMVD - Task & Environment
Ultra-low-mass, radiation-hard Ultra-low-mass, radiation-hard detector system detector system
782 rec. tracks2% ghost tracks
XZ
8 microstrip stations
MVD
J.M. Heuser − Silicon detector systems for CBM 22
MMonolithic A Active P Pixel D Detectors
Low-resistivity p-type Si hosting n-type charge collectors ("wells"):
signal created in epitaxial layer
Q ~ 80 e-h / μm signal < 1000 e−
charge sensed by n-well/p-epi junction
excess carriers diffuse towards diode
amplifier, CDS etc. on chip
thickness as thin as 50 µm
Cooperation with IPHC Strasbourg
pixel: 10 – 40 µm pitch
top view
J.M. Heuser − Silicon detector systems for CBM 23
100 kHz full-frame readout
Concept at IKF, University of Frankfurt
MVD R&D effort MVD R&D effort Radiation hard sensors > 1013 nequiv.
MVD demonstrator module
MAPS with column parallel readout
Material budget of full system: < 0.3% X0 or 300 µm Si
~ 5 cm
Potential MVD demonstrator station
at T= -20 C
ultimately:
Thin MAPS on thin industrial diamond support with integrated Al bus: 0.1-0.2 X0
(150 µm Si)R&D with IPHC & Fraunhofer
J.M. Heuser − Silicon detector systems for CBM 24
D (c = 312 m):D+ K-++ (9.5%)
D0 (c = 123 m):D0 K-+ (3.8%) D0 K- + + - (7.7%)
Ds (c = 150 m):D+
s K+ K- + (5.3%)
+c (c = 60 m):
+c pK-+ (5.0%)
c reconstruction: Greatest challenge!!
D0 z-vertex resolution
D+ reconstruction
Open Charm ReconstructionOpen Charm Reconstructionwith such a detector system ...
J.M. Heuser − Silicon detector systems for CBM 25
MVD +
STS
MUCH
TRD TOF
target
beam
PSD
CBM – Muon setupCBM – Muon setup
J.M. Heuser − Silicon detector systems for CBM 26
Track points in the first MUCH gap: similar to STS-8
10 MHz interaction rate
High radiation dose
Rather high granularity needed
No material budget limitNo material budget limit
Silicon pad detectors + fast self-triggered FEE. Under discussion.
UrQMD,Au+Au, 25 AGeV
MUCH-Si1 - MUCH-Si1 - Task & EnvironmentTask & Environment
Large-area (1.3 Large-area (1.3 STS-8), STS-8), fast, fast, radiation-hard detector system radiation-hard detector system
~ 1 hit/cm2/event(Geant study,
A. Kiseleva)
MUCH-Si1
J.M. Heuser − Silicon detector systems for CBM 27
Wafer thickness 525 µm
diode area 15 mm by 15 mm
Depletion voltage 100-120 V
Diode capacitance 37 - 41 pF
Bias for full depletion 20 V
Leakage current < 300nA total, <20nA/pad
Junction breakdown > 300V
Polysilicon bias resistor 1 M
from:
Proposal for a Nosecone Calorimeter (NCC) for the PHENIX Experiment
BNL, 3/2006 CBM01 wafer
Microstrip pad detectorsMicrostrip pad detectors
Area diodes; typical size ~ mm2 up to many cm2
Example: PHENIX pad detector prototypes (MSU/ELMA)
PHENIX pad detector prototypes
pad diode test structures, few mm2 area
J.M. Heuser − Silicon detector systems for CBM 28
sectorization study of 1st tracking station (zones of ~ same occupancy)
r = 0.8 m
sectors with 8 x 16 = 128 pads
possible "module"
(M. Ryzhinskiy)
Possible MUCH Si tracking stationPossible MUCH Si tracking station
# size pad size pad area sectors [cm x cm] [mm x mm] [mm2]
160 2.22 x 2.22 2.8 x 1.4 4
84 2.22 x 4.44 . .
64 4.44 x 4.44 . .
48 4.44 x 8.88 . .
28 8.88 x 8.88 . .
48 8.88 x 19.76 11 x 12.5 140
challenges:
• connection of r/o electronics to many SMALL pads
• check radiation env.
CBM-XYTER
— — From sectors to pads From sectors to pads ——
128 chs.
J.M. Heuser − Silicon detector systems for CBM 29
SummarySummaryCBM will comprise two, maybe three silicon detector systems
unprecendeted performance will be required
thin, fast, efficient/redundant, radiation hard: new/fully exploited state-of-the art technologies
challenge is especially in the system design
most important:
planning/evaluation in reliable simulation studies
characterization of prototypes from early on
STS: start to approach this phase simulation & prototyping
MVD: detector R&D active, system design/simulation mostly t.b.d.
MUCH-Si1: upcoming new activity, t.b. planned