Transcript Development of pixel detectors with integrated

Development of pixel detectors with
integrated signal processing for the
Vertex Detector in the STAR experiment
at the RHIC collider
PhD Thesis defense
Michal Szelezniak
ULP, Strasbourg
25 February 2008
Michal Szelezniak - PhD thesis defense - 25 February 2008
Outline
Development of pixel detectors with integrated
signal processing for the Vertex Detector in the
STAR experiment at the RHIC collider
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The new vertex detector for the STAR experiment
Development of Monolithic Active Pixel Sensors
(MAPS) at IPHC
MAPS prototype for PIXEL detector
3-sensor telescope system with prototype readout
for PIXEL detector
Future development plans
Summary and Conclusions
Michal Szelezniak - PhD thesis defense - 25 February 2008
STAR experiment
STAR was constructed to study
Quark-Gluon Plasma created in
heavy-ion collisions at Relativistic
Heavy Ion Collider (RHIC)
(a)
a)
b)
c)
d)
(b)
(c)
(d)
Lorentz contracted ions before the collision
Hard interactions between partons of incoming nuclei
New, high-density state of matter (QGP?)
Hadronization and freezout
Location of the
new vertex
detector
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End view of tracks registered by the
STAR TPC in a heavy-ion collision
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Michal Szelezniak - PhD thesis defense - 25 February 2008
QGP in heavy-ion collisions

Penetrating probes (created early in a collision) are sensitive to the
evolution of the medium
– Particles with very high transverse momentum
– Heavy particles containing charm or bottom quarks

To study next:
– Charm flow to test thermalization of light quarks at RHIC
– Charm energy loss to test pQCD in a hot and dense medium at RHIC
(from HFT proposal)
The D0 signal, after topological cuts, is
shown by the solid black circles.
The original spectrum, before software cuts,
is shown by the line of open circles.
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Michal Szelezniak - PhD thesis defense - 25 February 2008
HFT: new vertex detector for STAR
Heavy Flavor Tracker
PIXEL at 2.5 and 8 cm
IST at 14 cm
Secondary vertex
SSD at 23 cm
~100 µm
D0 (cū)
Primary vertex
To measure heavy flavor
production it is necessary to
measure charm and bottom
hadrons through direct
topological reconstruction
New Vertex Detector is needed!
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Goal: increasing pointing resolution from the
outside in
– TPC pointing resolution at the SSD is ~ 1 mm
– SSD pointing at the IST is ~ 300 µm
– IST pointing at the PIXEL is ~ 250 µm
– PIXEL pointing at the VTX is ~ 30 µm
–
PIXEL: spatial resolution < 10 μm
radiation length ~ 0.3 %
VXD3 0.4%, ALICE pixel detector ~1%
Michal Szelezniak - PhD thesis defense - 25 February 2008
PIXEL Detector
PIXEL characteristics:
Two layers at 2.5 & 8 cm radius
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10+30 ladders
10 sensors/ladder
Nearly 164 M pixels
0.28 % radiation length/layer
Air cooled
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Quick extraction and sensor
replacement
Monolithic Active Pixel Sensors
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–
–
–
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Ladder with 10
MAPS sensors
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RDO
buffers/
drivers
Thinned to 50 μm thickness
30 μm x 30 μm pixels
640 x 640 pixel array
Integration time <200 μs at L=8×1027
Power disspation <100 mW/cm2
MAPS
4-layer kapton cable with aluminium traces
Michal Szelezniak - PhD thesis defense - 25 February 2008
Development of pixel detectors with integrated
signal processing for the Vertex Detector in the
STAR experiment at the RHIC collider


The new vertex detector for the STAR experiment
Development of Monolithic Active Pixel Sensors
(MAPS) at IPHC
–
–
–
–
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

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Simulations and tests of in-pixel voltage amplifiers,
Tests of advanced pixel structures with in-pixel memories
Tests and study of AC coupling for in-pixel amplifiers
Tests and study of MAPS operated in current mode (PhotoFET)
MAPS prototype for PIXEL detector
3-sensor telescope system with prototype readout for
PIXEL detector
Future development plans
Summary and Conclusions
Michal Szelezniak - PhD thesis defense - 25 February 2008
Monolithic Active Pixel Sensors
MAPS pixel cross-section
(not to scale)
Properties:
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Thin active volume → MIP signal
limited to <1000 electrons
Thermal diffusion → cluster size of ~10
pixels (20-30 μm pitch)
sensitivity to charge of a few tens of
electrons ← noise at the level of 10 e-
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Standard commercial CMOS
technology
Sensor and signal processing
integrated in the same silicon wafer
Signal created in low-doped
epitaxial layer (typically ~10-15 μm)
Charge collection mainly through
thermal diffusion (~100 ns),
reflective boundaries at p-well and
substrate
Charge sensing in n-well/p-epi
junction
100% fill-factor
High granularity
Low power dissipation
Substantial radiation tolerance
Thinning available as standard
post-processing
Only NMOS transistors inside pixels
Michal Szelezniak - PhD thesis defense - 25 February 2008
MAPS vs. other technologies
Hybrid Pixel Sensors:
detector bump bonded to readout chip
CCD:
integrated detector and readout, external
processing
8” wafer with MAPS prototypes
MAPS:
integrated detector/readout/processing
High granularity (several μm pitch)
Small material budget
Fast readout
Radiation tolerance
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MAPS
+
+
+
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Hybrid Pixel Sensors
++
++
CCD
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+
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Michal Szelezniak - PhD thesis defense - 25 February 2008
Simple pixel architectures
Classical diode with reset
VDD
charge
collection
VDD
reset
select
reset
VDD
output
output
charge
collecting
diode
time
read
Reset noise, offset
GND
Continuous reverse bias (self-biased)
VDD
No reset noise, no offset
VDD
charge
collection
select
output
charge
collecting
diode
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10
a)
output
in equilibrium
GND
b)
read
time
Michal Szelezniak - PhD thesis defense - 25 February 2008
Pixel sensor architectures
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Typical sensor readout
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– Raster scan
– Charge integration time = array
readout time
– Multiplexed sub-arrays to decrease
integration time
Column parallel readout architecture
– All columns readout in parallel and then
multiplexed to one output
– Charge integration time = column
readout time
Analog readout – simpler architecture but ultimately slower readout
Digital readout – offers increased speed but requires on-chip discriminators or ADCs
On-chip signal processing requires high S/N – signal amplification is needed
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Michal Szelezniak - PhD thesis defense - 25 February 2008
Example of a simple in-pixel amplifier
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Amplifier in cascode configuration (only NMOS transistors)
(0.35 μm CMOS process)
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VDDA
Typical gain: 4-6
G
g m1
gm2
Vout
Typical power
consumption (3.3 V)
P=20 μW
Vcascode
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Typical biasing voltage:
~0.7 V
Vin
g m1
GND
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Switches for switched-power
operation
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Cascode transistor to
reduce the Miller effect that
is present in a commonsource configuration:
Cin = Cgs + Cgd(1+G)
gm2
power_on
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Lower input capacitance
 higher charge-to-voltage
conversion factor
Michal Szelezniak - PhD thesis defense - 25 February 2008
Optimization of pixel design
Typicala connection
bAC-coupling
vbias
vbias
biasing
diode
charge
collecting
diode
gain
out
gain
out
Compact layout
implementation of AC coupling
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Improves CCE (5%)
Degrades ENC (25%)
 DC coupling gives better
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ENC performance
Michal Szelezniak - PhD thesis defense - 25 February 2008
Investigated in-pixel amplifiers
VDDA
VDDA
VDDA
Design
gain = 8
Design
gain = 9
power_on
power_on
Vout
Measured
gain < 4.5
Basic Design
gain = 5
Vout
Measured
gain < 5
Vcascode
ENC = 20 e-
Vcascode
power_on
ENC = 18 e-
Vin
GND
Pixel with 2 internal memories
Measured
gain = 4
ENC = 12 e-
Vin
GND
E.g. memory discharge time:
MOSFET capacitor 7μm x 7μm (200 fF)
5s/div and 200 mV/div
Promising structure for on-chip CDS processing
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Michal Szelezniak - PhD thesis defense - 25 February 2008
MAPS operated in current mode
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PhotoFET cell – collected charge modulates
current in the PMOS transistor
Early prototypes: single cell ENC ~ 5e-
Tested in pixel array configuration
Two in-pixel current memory cells
Noisy prototype (ENC 50-60 e-) due to
large noise bandwidth
Coupling of digital signals to memory
nodes during sensor operation prevented
the use of the integrated CDS
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Signal distribution from one pixel
Michal Szelezniak - PhD thesis defense - 25 February 2008
CDS in current mode
Two
CDS performing circuits validated (in discrete implementation)
–Capacitance arithmetic (integrator + amplifier)
–Subtraction on an operational amplifier (two integrators + amplifier)
More compact architecture
Simpler subtraction – faster operation
Lower power consumption
More amplifiers – higher power consumption
PhotoFET – interesting concept and promising results
BUT
Not ready to provide a reliable solution for a vertex detector
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Michal Szelezniak - PhD thesis defense - 25 February 2008
Increased tolerance to ionizing radiation
Shot Noise Contribution @ 30°C
and @4 ms integration time
passiva tion
oxide
p+ FOX n+
p-epi
n+
p-well
FOX
n+
n-well
ENCshot = 39 electrons
FOX
depleted region
ENCshot = 12 electrons
p++ substrate
standard diode layout
passiva tion
oxide
gnd
gnd
p+ FOX n+
p-epi
n+ FOX n+
p-well
n+
n-well
depleted region
p++ substrate
thin-oxide diode layout
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Michal Szelezniak - PhD thesis defense - 25 February 2008
Development of pixel detectors with integrated
signal processing for the Vertex Detector in the
STAR experiment at the RHIC collider



The new vertex detector for the STAR experiment
Development of Monolithic Active Pixel Sensors
(MAPS) at IPHC
MAPS prototype for PIXEL detector
–
–
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

18
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Tests and study of performance as a function of ionizing
radiation dose
Tests and study of sensor’s susceptibility to latch up
3-sensor telescope system with prototype readout
for PIXEL detector
Future development plans
Summary and Conclusions
Michal Szelezniak - PhD thesis defense - 25 February 2008
On-chip data processing and complementary RDO
Data sparsification
reduction of the amount of
data transferred, typically
through zero-suppression
Correlated Double Sampling (CDS)
= subtraction of two consecutive signal samples
reduces low frequency noise
extracts signal accumulated during integration time
Complementary detector readout
Pixel
analog
signals
Sensors
ADC
CDS
digital
analog
CDS
Disc.
digital
signals
Data
readout
sparsification
to DAQ
MimoSTAR sensors
4 ms integration time
Phase-1 sensors 640 μs integration time
Ultimate sensors < 200 μs integration time
First prototypes in hand and
tested
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Few years back it was planned to built a
demonstrator detector based on sensors
with 4 ms integration time.
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2010
2011
Install 3-module demonstrator
(based on Phase1)
Install final detector
Michal Szelezniak - PhD thesis defense - 25 February 2008
MAPS Prototype for STAR
MimoSTAR2:
 Analog readout
 Radiation tolerant
diode design
 JTAG* controlled
configuration
*Joint Test Action Group (JTAG) is the IEEE
1149.1 standard entitled Standard Test
Access Port and Boundary-Scan
Architecture
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Michal Szelezniak - PhD thesis defense - 25 February 2008
MimoSTAR2 performance – ionizing radiation
55Fe
signal collected in central pixels
Peak corresponds
to the full charge
collection (1640 e-)
Degradation of noise performance
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60Co
Significant improvement
in resistance to ionizing
radiation
Satisfies initial PIXEL
detector requirements
Michal Szelezniak - PhD thesis defense - 25 February 2008
MimoSTAR2 performance – latch up
Setup at the
Tandem Van der
Graff accelerator
facility at BNL
Parasitic thyristor
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No latch ups observed
up to energies
equivalent to 6000 MIPs
Michal Szelezniak - PhD thesis defense - 25 February 2008
MimoSTAR2 performance – beam tests
Standard
setup for
tests with
minimum
ionizing
particles
reference planes
(strip detectors)
De vice
Un der
Test
reference planes
(strip detectors)
particle
tra ck
scintilator
scintilator
(5 GeV e@ DESY)
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detection
efficiency
> 99.8 %
when S/N
>12
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STD 0.8 ms
STD 4.0 ms
RAD 0.8 ms
RAD 4.0 ms
Analysis by Auguste Besson, IPHC
STD 0.8 ms
STD 4.0 ms
RAD 0.8 ms
RAD 4.0 ms
Michal Szelezniak - PhD thesis defense - 25 February 2008
Development of pixel detectors with integrated
signal processing for the Vertex Detector in the
STAR experiment at the RHIC collider




The new vertex detector for the STAR experiment
Development of Monolithic Active Pixel Sensors
(MAPS) at IPHC
MAPS prototype for PIXEL detector
3-sensor telescope system with prototype readout
for PIXEL detector
–
–
–
–
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Construction and tests of the telescope head
FPAG and software programming for JTAG communication
Study of efficiency of the proposed hit finding algorithm
Laboratory calibrations, ALS test and sensors alignment, tests
in the STAR environment
Future development plans
Summary and Conclusions
Michal Szelezniak - PhD thesis defense - 25 February 2008
Motivation for the 3-sensor telescope
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The telescope is a small prototype and contains all elements
easily scalable to meet the requirements of the PIXEL
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Test functionality of a prototype MIMOSTAR2 detector in the
environment at STAR 2006-2007:
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Charged particle environment near the interaction region in STAR.
The noise environment in the area in which we expect to put the final
PIXEL.
Performance of the MIMOSTAR2 sensors.
Performance of our hit finding algorithm.
Performance of our hardware / firmware as a system.
Functionality of our tested interfaces to the other STAR subsystems.
Michal Szelezniak - PhD thesis defense - 25 February 2008
Implementation of the 3-sensor telescope
Analog signals
Clock & control
JTAG
LU prot. Power
MIMO
STAR
2
MOTHER
BOARD
MIMO
STAR
2
Analog signals
Clock & control
Cluster FIFO
Hot Pixel Map
Memory Access
(for full frame)
Trigger info
Power
Motherboard
DAUGHTER CARD
Daughtercard
MIMO
STAR
2
MimoStar2 chips on kapton cables
Trigger, Clock
from MWPC
Control PC (Win)
Trigger, Clock
Cluster FIFO
Busy to trigger
Power
from MWPC
JTAG
x3 for MIMOSTAR
x1 for daughtercard
PC
(WIN)
Stratix
Latch up
monitor and reset
JTAG
STRATIX
serial / ip connection
DDL to Linux PC
Acquisition Server (Linux)
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control conection
to PC in DAQ room
power
RORC SIU
Michal Szelezniak - PhD thesis defense - 25 February 2008
Zero suppression through on-the-fly hit finding
Functionally equivalent to a raster scan
Cluster Finding Saving Address Only
pixel
address
counter
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Enable
Cluster sensor operates
on these 9 pixels
To
Event
Builder
Checks 9 pixel window at each clock cycle
Only pixel addresses are saved
shift register length = 1 column
8-bit post-CDS
data
50 MHz data
stream.
row n-1
row n
row n+1
column
n+1
high
thresh.
column
n
column
n-1
Hits are recognized when:
1. signal in the central pixel exceeds high threshold
2. and any one of the neighboring 8 pixels exceeds
low threshold.
Efficiency and accidental rates are comparable to the
traditional ADC sum method.
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Michal Szelezniak - PhD thesis defense - 25 February 2008
Cluster Finder Efficiency
Sum method
Two Threshold FPGA method
Cut on the central pixel goes from 14 to 8 ADC counts (left to right) every 1 ADC = 7.1 e-
Detection efficiency >99% and accidental hit rate <10-4
achievable for a range of settings
Expected close to 3 orders of magnitude data rate reduction
for a 4 ms PIXEL detector
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Michal Szelezniak - PhD thesis defense - 25 February 2008
MimoSTAR2 Telescope test at the ALS
1.2 GeV electrons at the ALS Booster
Test Facility
Due to not decoupled DAC pads on
the sensor, our noise level was double
the value achieved under normal
conditions.
Decoupled
 11-15
Not decoupled  30-35 e@ 30º C
e-
Sensors aligned based on straight tracks
reconstructed in all 3 planes
Scan of threshold levels to calibrate
the system for the next stage of tests
in the STAR environment
• High cut 25 ADC
• Low cut 14 ADC
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MPV = 49 (Standard) and 43
(Radtol) ADC counts at ~230
electrons
Michal Szelezniak - PhD thesis defense - 25 February 2008
MimoSTAR2 Telescope test at STAR
(Run 200 GeV Au-Au)
Magnet Pole Tip
The interraction point is ~2 m away
Telescope head
145 cm from interaction point
5 cm below beam pipe.
Beam Pipe
Electronics Box
View of TPC end cap
signals originating at
the collision point
Background tracks
parallel to the beam
(magnified)
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No environmentally induced noise
observed
Operation in magnetic field of 0.5 T
Average RHIC luminosity 8×1026 cm-2s-1
On average 25 clusters per cm2 per frame
(1.7 ms)
of the complete
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system
was validated
Increased width from
multiple Coulomb
scattering in the
beam pipe
 Operation
Analysis by Xiangming Sun, LBL
theoretical
projection of
the beam
diamond
Michal Szelezniak - PhD thesis defense - 25 February 2008
Development of pixel detectors with integrated
signal processing for the Vertex Detector in the
STAR experiment at the RHIC collider






31
31
The new vertex detector for the STAR experiment
Development of Monolithic Active Pixel Sensors
(MAPS) at IPHC
MAPS prototype for PIXEL detector
3-sensor telescope system with prototype readout
for PIXEL detector
Future development plans
Summary and Conclusions
Michal Szelezniak - PhD thesis defense - 25 February 2008
What will a pixel for the PIXEL look like?
MAPS developed for STAR started with a
very simple pixel architecture
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The simplest pixel
Sequential pixel readout
Currently, the most promising architecture
developed by IPHC and CEA-Saclay
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Meets PIXEL
requirements
In-pixel amplifier
In-pixel CDS
Column parallel readout
On-chip discriminators
There is always room for improvements
… and we still have a little bit of time
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Mimosa
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Michal Szelezniak - PhD thesis defense - 25 February 2008
Final detector system
Under development
+
Currently in
the testing
phase
Pixel
Pixel
Sensors
analog
signals
Disc.
CDS
digital
signals
Data
readout
sparsification
to DAQ
Phase-1 sensors – 640 μs integration time
Ultimate sensors – <200 μs integration time
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2010
2011
Install 3-module demonstrator
(based on Phase1)
Install final detector
Michal Szelezniak - PhD thesis defense - 25 February 2008
Development of pixel detectors with integrated
signal processing for the Vertex Detector in the
STAR experiment at the RHIC collider






34
34
The new vertex detector for the STAR experiment
Development of Monolithic Active Pixel Sensors
(MAPS) at IPHC
MAPS prototype for PIXEL detector
3-sensor telescope system with prototype readout
for PIXEL detector
Future development plans
Summary and Conclusions
Michal Szelezniak - PhD thesis defense - 25 February 2008
Summary and Conclusions
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MAPS development is keeping pace with requirements for STAR
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MimoSTAR2 prototype was a necessary precursor to the final STAR
PIXEL sensor
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–
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Development of pixels for on chip CDS processing
(in-pixel amplifiers, on chip CDS, alternative current mode)
Validation of the technology based on the first prototypes
Development and testing of the PIXEL detector readout system
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The existing sensor architecture with column parallel readout should
satisfy PIXEL detector requirements
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IPHC-LBL development plan leads us to achieving the design goals in
the next few years (2010 – detector demonstrator, 2011 final installation)

PIXEL detector is going to be the first vertex detector built with MAPS
technology – significant impact on the HEP field
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Michal Szelezniak - PhD thesis defense - 25 February 2008
Thank you for your
attention
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Michal Szelezniak - PhD thesis defense - 25 February 2008
Backup Slides
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Michal Szelezniak - PhD thesis defense - 25 February 2008
Introduction to the STAR experiment

Penetrating probes (created early in a collision)
are sensitive to the evolution of the medium
Particles with very high transverse momentum
Heavy particles containing charm or bottom quarks
–
–

Some of the observed physics:
Suppression of the side-away jets
Flow
source

To study next:
–
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source
38
–
Production of heavy quarks
Elliptic flow of heavy quarks
Michal Szelezniak - PhD thesis defense - 25 February 2008
QGP in heavy-ion collisions

Penetrating probes (created early in a collision) are sensitive to the
evolution of the medium
– Particles with very high transverse momentum
– Heavy particles containing charm or bottom quarks

To study next:
– Charm flow to test thermalization of light quarks at RHIC
– Charm energy loss to test pQCD in a hot and dense medium at RHIC

Selected result: spectra of heavy quarks
The corresponding heavy flavor
decayed electron spectra are shown as
black curves.
Single electron/positron spectra from
semileptonic decays are not sufficient.
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S. Batsouli et al. Phys. Lett. B557, 26 (2003)
Michal Szelezniak - PhD thesis defense - 25 February 2008
D0 reconstruction
(from HFT proposal)
The D0 signal, after topological cuts, is shown by the solid black circles.
The original spectrum, before software cuts, is shown by the line of open circles.
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Michal Szelezniak - PhD thesis defense - 25 February 2008
STAR pointing resolution
Pointing resolution of the TPC alone
Pointing resolution at the vertex by the
TPC+SSD+IST+PIXEL detectors
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Michal Szelezniak - PhD thesis defense - 25 February 2008
PIXEL development plan
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Original plan (2006)
08 2007
08 2008
Wafers of full-reticule
MimoSTAR4
Install 4ms detector
(based on MimoSTAR4)
06 2011
Install final detector
 analog readout
 binary readout
 4 ms integration time
 640 μs integration time
New plan (2007)
03 2008
08 2010
Submit Phase1 for
fabrication
Install 3-module demonstrator
(based on Phase1)
06 2011
Install final detector
 binary readout
 binary readout
 binary readout
 640 μs integration time
 640 μs integration time
On-chip zero suppression
 200 μs integration time
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Michal Szelezniak - PhD thesis defense - 25 February 2008
MimoSTAR2 Telescope test at the ALS
Electronic noise background
Merged cluster data – typically 2-3 hits per cluster.
Increased noise in sensors results in reduced performance.
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Michal Szelezniak - PhD thesis defense - 25 February 2008
PIXEL Data Rates for a 4ms detector
MIMOSTAR
Sensors
Analog
Signals
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50.7GB/s
GB/s
ADCs
ADCs
ADCs
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GB/s
38 GB/s
CDS
168
MB/s
114 MB/sec
Hit
Finder
+ address
DAQ EVENT
BUILDER
Rate @ R1 (2.5 cm) = 52.9 / cm2
Rate @ R2 (8 cm) = 7.3 / cm2 (at L = 1027 cm-2s-1)
Average event size = 168 kB *
Data Rate = 168 MB/s at 1 kHz *
On average 2.5 pixels per cluster
*Bit rate without any overhead
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Michal Szelezniak - PhD thesis defense - 25 February 2008
PIXEL ladder
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Michal Szelezniak - PhD thesis defense - 25 February 2008
Telescope results
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RDO system with on-the-fly data sparsification
implemented and functional for Mimostar2
sensors.
Prototype system fully functional and
characterized.
Fully functioning interfaces between the
prototype system and STAR detector
infrastructure.
Completed measurements of detector
environment at STAR.
Michal Szelezniak - PhD thesis defense - 25 February 2008
Fast, column-parallel architecture
PIXEL
Developed in IPHC - DAPNIA collaboration
COLUMN CIRCUITRY
VREF1
PWR_ON
VREF2
VDD
RESET
READ
PWR_ON
CALIB
VR1
VR2
MOSCAP
Vin1,2
READ
SOURCE
FOLLOWER
CALIB
VC
-
Q
-
A1+Voff1
A2,+ Voff2
+
+
-
-
READ
VREAD,CALIB
VS_READ
ISF
READ
latch _
Q
LATCH
OFFSET COMPENSATED COMPARATOR
(COLUMN LEVEL CDS)
PWR_ON
CDS at column level (reduces Fixed Pattern Noise below
temporal noise)
RESET
READ
CALIB
LATCH
VCALIB  Vref 2  Vsf , VC  Vref 2 Vin1
VREAD  Vin2  VC  Vsf 
 Vin2  Vsf  Vref 2  Vin1 
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 Vref 2  Vsf  (Vin2  Vin1 )
VS _ READ 
A2
Voff 2   A1 VREAD  VR 2  Voff 1 
1  A2
Vout   A2  A1 VCALIB  VR1  Voff 1   Voff 2  VS _ READ 
Vout  A2 A1 VCALIB  VREAD   VR 2  VR1 
Michal Szelezniak - PhD thesis defense - 25 February 2008
Next generation of prototypes
48

Radiation tolerant diode design

Column parallel readout with on-chip discriminators

Binary readout

JTAG controlled configuration

On-chip zero suppression (currently at prototyping stage)
48
Michal Szelezniak - PhD thesis defense - 25 February 2008
Summary and Conclusions

An architecture of the MAPS sensor that should comply with the final
PIXEL detector requirements exists and provides very promising initial
results

The on-going development of pixel architectures and in particular inpixel amplifiers has a potential of further improving the established
performance

Readout architecture for the PIXEL detector has been prototyped and
validated
–
–

49
Reading out sensors with binary output will require adjustments w.r.t. the existing
solution (fast LVDS readout)
Detector dead-time is primarily limited by the number of externally allocated readout
buffers
The next mile-stone for MAPS and PIXEL development will integrate
the new full-size (640×640 pixels) sensor prototype (Phase-1 under
development), prototype mechanical support and new readout system
for fast binary sensor readout
49
Michal Szelezniak - PhD thesis defense - 25 February 2008
Development of pixel detectors with integrated
signal processing for the Vertex Detector in the
STAR experiment at the RHIC collider

The new vertex detector for the STAR experiment
–
–
–





50
50
Introduction to the STAR experiment
HFT: new vertex detector for STAR
PIXEL detector
Development of Monolithic Active Pixel Sensors
(MAPS) at IPHC
MAPS prototype for PIXEL detector
3-sensor telescope system with prototype readout
for PIXEL detector
Future development plans
Summary and Conclusions