Download CAP Pixel Status Update

Progress in the Development of a
B-Factory Monolithic Active Pixel
Detector
Samo Stanič for the Belle Pixel Group
M. Barbero1, A. Bozek4, T. Browder1, F. Fang1, M. Hazumi3, J. Kennedy1,
N. Kent1, S. Olsen1, H. Palka4, M. Rosen1, L. Ruckman1, S. Stanič2,
K. Trabelsi1, T. Tsuboyama3, K. Uchida1, G. Varner1 and Q. Yang1
1University
of Hawaii, 2 University of Tsukuba,
3 High Energy Accelerator Research Organization (KEK),
4 H. Niewondiczanski Institute of Nuclear Physics
SVD Upgrade Meeting 2005/04/12
Motivation
SuperKEKB luminosity increase:
L~1.5 x 1034 → L~5 x 1035 cm-2.s-1
Conventional solutions (Si strips)
will not work…
2. Improve impact parameter
resolution?
~10%
~4%
~2%
~2%
Present
Belle SVD2
1. Reduce SVD occupancy
Present : layer 1 of SVD
~10% occupancy / 200 Krad.yr-1
Upgrade: Super-Belle
~ 20 – 50 x (?) expected
background increase
Samo Stanič for the Pixel Group - 2005/4/12
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Solution at hand: “Striplet”
• New type of short DSSD sensors: “Striplets”
– Shorter strip length, strips arranged at 45 degrees
– Small triangle dead region exists (about 7 % in layer1)
– Readout by APV25 chip developed for CMS @ CERN
– Occupancy is reduced to ~5% @L= 1035/cm2/s
– Operation confirmed in beam-test @ KEK by the
Vienna Group
… Higher luminosity than that requires pixel type sensor!
Z
Dead region
U
10mm
rφ
14mm
70mm
V
From T. Kawasaki-san, Niigita-U, 6th HL WS, 2004/11
Samo Stanič for the Pixel Group - 2005/4/12
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Natural alternative - Pixel type sensor
Requirements
R&D steps
Technology Choice
1. Low occupancy
XTEST2, LHC
hybrid pixels
MAPS
2. Fast Readout Speed
4. Thin Sensor
5. Full-sized detector
prototype
Prototypes
3. Radiation Hardness
CAP1 – basic functionality
Jun. 2004
@ KEK
CAP2 – pipelined readout
T943 Dec.
2004 @
FNAL
CAP3 – full-size/speed
T569 ~ Jun.
2005 @ KEK
Preliminary Design Report
PVD1.0
 Near Term (SVD2 Layer 1 drop-in)
 IR upgrade
Samo Stanič for the Pixel Group - 2005/4/12
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Belle Pixel Sensor Evolution
CAP1
basic functionality
technology choice
2003
CAP2
CAP3
2004
full-size/speed
pipelined readout
2005
Samo Stanič for the Pixel Group - 2005/4/12
PVD1.0
time
final detector
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Candidate: Monolithic Active Pixel Sensor
Current DSSD
MAPS
10mm
300mm
Because of large
Capacitance, need
Thick DSSDs
-- APS can be VERY
Thin
Key Features
•Thermal charge collection (no HV)
• Thin - reduced multiple-scattering, g
conversion, background g target
• NO bump bonding – fine pitch possible
(8000x geometrical reduction)
• Standard CMOS process - “System on
Chip” possible
Samo Stanič for the Pixel Group - 2005/4/12
5
Continuous Acquisition Pixel (CAP) Concept
Based on 3 transistor cell
V_Q_integr
Vreset
Reset
Δvtyp α Ileak
M1
Collection
Electrode
M2
M3
Δvsig α Qsignal
Bus
Output
time
Integration time
reset
Pixel
tfr1
Array of pixels
tfr2
ADC
High-speed
Analog
read-out
& storage
Pixel Array: Column select – ganged row read
Samo Stanič for the Pixel Group - 2005/4/12
Low power – only significant
draw at readout edge
6
CAP1 – Basic operation confirmed
CAP1: simple 3-transistor cell
TSMC 0.35mm Process
Vdd
Vdd
Source follower buffering
of collected charge
Reset
M1
M2
Restores potential to
collection electrode
Collection
Electrode
M3
Row Bus
Output
Gnd
Column Ctrl Logic
Pixel size:
1.8
mm
22.5 mm x 22.5 mm
Column
Select
132col x 48row ~6 K pixels
CAPs sample tested: all
detectors (>15) function.
Samo Stanič for the Pixel Group - 2005/4/12
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Correlated Double Sampling (CDS)
(
-
)
8ms integration
Frame 1 - Frame 2 =
Can readout/process
@ 20Hz ~ 16% live time (CAP1!)
Self-Triggering mode
- Leakage current
Correction
~fA leakage current (typ)
~18fA for hottest pixel shown
Hit candidate!
Samo Stanič for the Pixel Group - 2005/4/12
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Hit resolution measurement
250mm Si
1mm Alumina substrate
1mm plastic
4.6 cm
3.6 cm
3.4 cm
L4
x-plane
L3
L2
z-plane
(in mm)
“hit”
Residuals for 4GeV/c pions:
< 11mm (in both planes)
Samo Stanič for the Pixel Group - 2005/4/12
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Radiation damage
Leakage Current (cont.)
Belle CAP1 Prototype
# of pixels
Before irrad.
200 Krad
Fully
annealed
Leakage Current [fA]
G. Varner, Monolithic Active Pixel Sensor R&D, STD5 Hiroshima – 15 JUN 04
26
IEEE Trans. Nucl. Sc. 48, 17961806,2001
Samo Stanič for the Pixel Group - 2005/4/12
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Peak pixel S/N prediction
SNR (MPV peak) vs. Irradiation (300e- signal, 16e- system noise)
Peak Pixel Signal-to-Noise Ratio (SNR)
20
18
16
14
8ms
12
10us
10
100us
8
1ms
6
4
2
0
0.01
0.1
1
10
Radiation dose [MRad]
Samo Stanič for the Pixel Group - 2005/4/12
100
Extrapolation from upper edges
of Eid et al.
11
CAP2 – Pipelined operation
TSMC 0.35mm
132 x 48
8 deep mini-pipeline
3-transistor cell in each cell
132x48=6336 channels 50688 samples
10ms frame acquisition speed achieved!
Pixel size 22.5 mm x 22.5 mm
Samo Stanič for the Pixel Group - 2005/4/12
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CAP3 – Full scale pipelined prototype
5-deep double pipeline
TSMC 0.25mm Process
36 transistors/pixel
5 sets CDS pairs
Samo Stanič for the Pixel Group - 2005/4/12
5 metal layers
13
CAP3 - sensor layout
21 mm
Active area
20.88 mm
928 x 128 pixels = 118,784
>93% active without active edge
processing
~4.3M transistors !
Samo Stanič for the Pixel Group - 2005/4/12
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CAP3 readout
F3 frontend readout board manufactured,
laboratory testing is under way…
CAP3
However:
•Some parts still missing
•CAP3 firmware still under
development
May be a few weeks delayed
F3 board
Samo Stanič for the Pixel Group - 2005/4/12
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CAP3 based full detector concept
Half ladder scheme
CAP3
5-layer flex
Pixel Readout Board (PROBE)
PIXRO1 chip
128 x 928 pixels, 22.5mm2
~120 Kpixels / CAP3
0.25 mm process
End view
Side view
Double layer, offset structure
Length: 2x21mm ~ 4cm
r~8mm
30o
e-
r~8mm
17o
e+
# of Detector / layer ~ 32
Samo Stanič for the Pixel Group - 2005/4/12
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“Fast” Belle SVD2 L1 upgrade option
~10%
~4%
~2%
~2%
Replace Layer 1 with CAP3 pixels
Mechanically identical (drop in)
Flex
CAP3
Samo Stanič for the Pixel Group - 2005/4/12
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Belle SVD L1 upgrade
Flex
CAP3
4 x 9 = 36 CAP3 / L1 ladder
6 ladders/L1 layer
~26M Channels total
Scaling current SVD L1 * 4 background ~ few kBytes/event
R=7mm configuration: 6.6M channels
SVD L1 * 40 background ~ few 100kBytes/event
With L3 track match: ~few 10kBytes/event
Samo Stanič for the Pixel Group - 2005/4/12
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CAP3 Beam-test at KEK
Possibility of CAP3 beam test in the end of June 2005 as the last
experiment at the KEK PS before its permanent shut-down
We are fighting against the tight schedule and looking forward to new results!
Samo Stanič for the Pixel Group - 2005/4/12
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Summary: Critical R&D Milestones
1. Readout Speed
100kHz frame rate, 10kHz L2 accept
10ms frame acquisition OK (CAP2), CAP3 to test 100ms frame readout
2. Radiation Hardness
>= 20MRad
Leakage current OK (CAP2), q collection efficiency TBD
3. Thin Detector
<= 50mm, double layer
50mm mechanical dummies, CAP3 to be thinned (SNF)
4. Full-sized detector
Span acceptance (reticle limit)
CAP3 fabricated – performance evaluation
Samo Stanič for the Pixel Group - 2005/4/12
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Samo Stanič for the Pixel Group - 2005/4/12
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