D

1
DØ Silicon Microstrip Tracker
DØSMT

• Design
• Production
• Assembly
• Readout
• Installation
• Commissioning
• Conclusions

• Eric Kajfasz (CPPM/FNAL) - Breese Quinn (FNAL)
• Como, October 15, 2001
• presented by Alice Bean (Kansas/FNAL)

2
SMT Design
12 F Disks
4 H Disks
6 Barrels

• 4-layer barrel cross-section

SMT Statistics
72 ladders 12 cm long
6192 R/O chips 792,576 channels gt 1.5
million wire bonds
3
SMT Design
4
High Density Interconnect

• Kapton based flex circuits with0.2 mm pitch for
  chip mounting
• Laminated to Beryllium substrateand glued to
  Silicon sensor
• Connects Sensor to SVXII chips and SVXII chips to
  flex circuit via wire bonds(Al wedge bonding)
• Connects to a Low Mass Cable which carries the
  signals out of the interaction region

5
SVXIIe chip

• 1.2 um CMOS amplifier/analog delay/ADC chip
  fabricated in the UTMC rad hard process
• Designed by LBL/FNAL
• Some features
• 128 channels
• 32 cell pipeline/channel
• 8-bit Wilkinson ADC
• Sparsification
• 53 MHz readout
• 106 MHz digitization
• 6.4 x 9.7 mm2
• About 85,000 transistors

6
SVXIIe chip

• Externally programmed to achieve optimal
  performance for 132 or 396ns beam crossings and
  detector capacitances from 10 to 35pF (preamp
  bandwidth adjustment)
• Chip noise490e 50e/pFi.e. 1200e ENC for
  C15pF1 MIP gt 4fC gt 25,000egt S/N 20
• Max dealy in analog pipeline32 x 132ns 4.2us

7
Production 3-chip ladders

• 72 single-sided axial ladders
• 2 sensors/ladder
• Located on 1st and 3rd layer of 2 outer barrels
• Be substrate, HDI and rohacell foam/carbon fiber
  rails glued on Silicon sensor

8
Production 6-chip ladders
N-side
P-side

• 144 double-sided double-metal axial/90 ladders
• 1 sensor/ladder
• Located on 1st and 3rd layer of 4 inner barrels

• Be substrate, HDI and rohacell foam/carbon fiber
  rails glued on Silicon sensor

9
Production 9-chip ladders
N-side
P-side

• 216 double-sided axial/2 ladders
• 2 sensors/ladder
• Located on 2nd and 4th layer all 6 barrels

• Be substrate, HDI and rohacell foam/carbon fiber
  rails glued on Silicon sensor

10
Production F-wedges
N-side
P-side

• Silicon sensor glued on HDI

• 144 double-sided 15 strips
• 6 (n) and 8 (p) readout chips
• 1 sensor/wedge
• Located on 12 F-disks

11
Production H-wedges

• 96x2 back to back single-sided, 7.5 strip
  angles
• 6-chip readout per side
• 2 sensors/wedge
• Be substrate and HDI glued on Silicon sensor
• Located on 4 H-disks

12
Production Sensor problems

• Sensor lithography defects
• A silicon manufacturing problem produced p-stop
  isolation defects in the 90 stereo ladders.
  This resulted in a 30 yield from the
  manufacturer.

• Micro-discharge effect
• With negative p-side bias on double-sided
  detectors, we observed micro- discharges
  producing large leakage currents and noise above
  a certain breakdown voltage.
• The effect occurs along the edges of the p
  implants, where large field distortions and
  charge accumulations result from misalignment of
  electrodes with implants.

13
Production Testing

• Functional Test
• Debug bad strips (broken capacitors), bonds,
  chips, etc.
• Determine the V-I characteristics of the sensors
• Measure V-max p-side breakdown voltage
  (micro-discharge effect)
• Burn-in
• Bias the ladder or wedge and test the readout for
  72 hours
• Measure pedestals, noise, gain and check sparse
  readout
• Laser
• Expose biased detectors to a narrow laser scan
• Measure the depletion voltage and leakage
  currents and identify dead channels
• Readout tested again after the detector is
  mounted on a barrel or disk

V-max
Fail
14
Production Rates
Production mainly paced by problems with HDIs and
Silicon sensors (yields, delivery delays )
15
Production Vop
L6
L3
Vop (V)
Vop (V)
FW
L9
Vop (V)
Vop (V)
16
Production V-max
L6
L9
V-max (V)
V-max (V)
FW
V-max (V)
17
Production Detector Quality

• Detector classification
• Dead channel lt 40 ADC count response to laser
• Noisy channel gt 6 ADC count pedestal width
• Grade A less than 2.6 dead/noisy channels
• Grade B less than 5.2 dead/noisy channels
• Only used mechanically OK Grade A and B detectors

Channel Fractions ()
18
Production dead channels
L3
dead strips
L6-p
L6-n
dead strips
dead strips
L9-p
L9-n
dead strips
dead strips
FW-p
FW-n
dead strips
dead strips
19
Assembly Barrel alignment

• Ladders placed on barrels using an insertion
  fixture
• Internal alignment done using a CMM(touch probe)

20
Barrel2 alignment - rotations
In the plane of the ladder
Around ladder short axis
Around ladder long axis
10um
48um
48um
?
(mm)
?
(mm)
(mm)
s(d)
48um induces a 3um error
48um induces a 2um error
s(g)
10um induces a 3um error
s(D)
21
Assembly Barrel-Fdisk mating
22
Assembly End Fdisks mating
23
Assembly Hdisk
24
Assembly Radiation monitors
25
Assembly ½-cylinder
HDI connection to low-mass cable
South Half Cylinder
26
SMT Readout Data Flow
HV / LV
I,V,T Monitoring
8 Low Mass Cable
19-30 High Mass Cable (3M/80
conductor)
25 High Mass Cable (3M/50 conductor)
3/6/8/9 Chip HDI
KSU Interface Board
CLKs
CLKs
Adapter Card
SEQ
SEQ
SEQ
Sensor
SEQ Controller
Optical Link 1Gb/s
Detector volume
Platform
Serial Command Link
VRB
VRB
VRB
VBD
PwrPC
1 5 5 3
VRB Controller
VME
L3
VRC
Counting House
SDAQ
27
SMT Readout Electronics

• Interface Boards
• 8 crates (144 boards) located inside the detector
  volume
• Regenerates signals
• SVX monitoring and power management
• Bias voltage distribution

• SEQuencers
• 6 crates (120 boards) located on the detector
  platform
• Use SVX control lines to actuate acquisition,
  digitization and readout
• Convert SVX data to optical signals

• VRBs (VME Readout Buffers)
• 12 crates (120 boards) located in counting house
• Data buffer pending L2 trigger decision
• Input _at_ 5-10 kHz L1 accept rate 50 Mb/s/channel
• Output _at_ 1 kHz L2 accept rate 50 Mb/s

28
Installation
Fiber Tracker

• Cylinder installation was completed on 12/20/00
• A ½ cylinder of 3 barrels and 6 F disks was
  inserted into each end of the CFT bore
• H Disk installation was completed on 2/6/01
• The cabling (15,000 connections) and electronics
  installation was completed in May 2001

Calorimeter
Low Mass Cables
SMT
High Mass Cables
Interface Boards
29
Commissioning Status

• The entire detector has been connected and
  powered
• The 30 glycol water coolant is refrigerated at
  10 degC (gt detectors run between 5 and 0 degC)
• 15 of the devices are not in the readout
• 10 ladders, 18 F wedges, 20 H wedges
• Problems could be with boards, cables,
  connectors, chips, etc. We will debug each of
  them during the October/November shutdown, and
  expect to recover at least half of them.
• Currently collecting calibration, alignment and
  commissioning data

30
Commissioning Event Display

• Online SMT event display

31
Commissioning Monitoring

• Online event monitoring program

32
Commissioning Charge Collection

• A cluster is defined as a contiguous sequence of
  strips with
• Each strip ? 6 ADC counts
• Cluster ? 12 ADC counts
• 1 MIP 25 ADC counts
• One can play on
• Timing settings, i.e. the delay of the
  integration window w.r.t. the beam crossing
• Preamp bandwith (pabw)

33
Commissioning Timing and S/N

• Higher preamp bandwith does not significantly
  reduce noise on n-side

4x132ns 1x18ns 0x2ns
Highest value ? smallest bandwith
34
Commissioning Calibrations

• SMT pedestal, noise and gain measurements are
  taken using SDAQ.
• Pedestal and noise measurements are used to
  calculate the threshold per chip to be used in
  sparse read out

35
Barrel cluster charge vs eta
MC
data
36
6-chip ladder n-side cluster size fraction vs eta
37
SMT CFT Track Matching

• Tracks were found separately in the SMT and the
  Central Fiber Tracker (CFT)
• SMT tracks were extrapolated to the CFT at which
  point the track offsets were measured
• Magnet off data

?r? -3 ? 36 ?m
38
SMT-CFT primary tracks
39
Conclusions

• Design/Production
• Experience with double-sided detectors has led to
  the decision to use single-sided silicon for the
  upgrade.
• Should work towards simpler designs in the
  future. For example, using 6 different sensor
  types resulted in extensive logistical
  complications.
• Had to overcome numerous vendor related problems
  for HDIs, Silicon Sensors, jumpers, low mass
  cables
• Assembly/Installation
• First alignment results show that the DØ SMT was
  assembled and installed very well.
• The installation in the D0 detector went rather
  smoothly. The biggest challenge to overcome was
  the lack of real estate. The D0 detector, when
  first designed, was unfortunately not designed
  with a Silicon detector in mind

40
Conclusions

• Commissioning
• The SMT was the first major DØ Upgrade detector
  system fully operational for Run 2a. More than
  85 of the channels were available for readout on
  startup, and most of the remaining channels will
  be debugged and recovered by November.
• Calibrations and first look at physics show that
  we understand our detector.
• The offline software is debugged at the same time
  as the hardware. Now that they are both
  reasonably stable, we can start systematic
  studies.
• The detector should be commissioned by the end of
  the year.
• We are eager to start doing good physics with it.
• General
• Construction and commissioning of the SMT has
  been an adventure full of challenges. But thanks
  to the relentless efforts of many physicists,
  engineers and technicians, D0 has now a vertex
  detector to play with.
• We had so much fun building this detector for run
  2a that we are already planning to build a
  completely new Silicon Microstrip detector for
  run 2b (see Alices talk)