# Presentation: 125606

## The D0 Silicon Microstrip Tracker

-                                Alice Bean
-                                for the D0 SMT group
-                                *Univ. of Kansas/Fermilab*
-                                                        Hiroshima STD Conference
-                                                        March 22, 2000

## Goal - D0 detector starts taking dataMarch 1, 2001

- Design
- Sensors
- Production
- Electronics and DAQ
- Assembly
- Schedule

- Outline

## Tracker Design

- Major Subsystems:
- single sided ladders (3-chip)
- double sided ladders (20, 9-chip)
- double sided ladders (900, 6-chip)
- F-Disks (DS - 8+6 chip)
- H-Disks (SS back to back - 6 chip)

- barrel

## Tracker Design

- Total ~793,000 channels
- Silicon Area   3.0 m2 of which 1.57 m2 is double sided
- intermediate in size between previous generation of collider detectors and LHC

## Production Steps

- Obtain and test sensors
- HDI fabrication and testing
- Ladder/Wedge production
- Ladder/Wedge testing
- Barrel/Ring Assembly

## Sensors

- Barrels: 3 types of detectors in 4 layers    All made at MICRON
- 72 single sided barrel detectors (3-chip ladders)
- single sided, AC coupling, Pitch 50 m
- all sensors received
- tested, 75% yield @ 99.5% good strips
- problem with flatness-may affect alignment

- 6cm

- 

## Sensors- cont.

- 216 20-stereo barrel detectors (9-chip ladders)
- double sided, 20-angle
- 50m (p-side) and 62.5 m (n-side) pitch
- have enough sensors in hand
- typical depletion voltages 20-40V

## Sensors - cont.

- Barrels:
- 144 900-stereo barrel detectors (6-chip)
- double sided, double metal in 6’’ technology
- 50m (p-side) and 153 m (n-side) pitch

- n+-strips

- 2nd metallization layer

- AC-capacitor pads for SVXII bonds

## Sensors - cont.

- 144 900-stereo barrel detectors (6-chip)- problems
- p-stop isolation                                                        defect on mask has                                                 helped to make yield                                                  low (30% )
- production rate a                                                 problem, we will have                                                  to accept lower grade                                            devices to meet                                                     schedule

## Sensors - cont.

- Disks:
- F-wedge detectors (144)
- double sided wedges with ±150 , 50 m (p-side) and 62.5 m (n-side) pitch, variable strip length
- all sensors in hand from Micron with typical depletion voltages of 60-70V
- have an order with Eurisys for balance of sensors - problems with low micro- breakdown voltage (70V) and schedule.

## Sensors - cont.

- Disks:
- H-wedge detectors, need 192 with 6-chip HDI readout
- 40 m strip pitch, single sided, AC coupled
- glued back to back with ±7.50
- sensors produced at ELMA near Moscow, we are waiting on an order for spares and backups
- typical depletion voltages 60V and work up to 150V

## Sensor Testing

- Check on all detectors:
- leakage currents (<0.5A/cm2 @ 2@Udepl)
- depletion voltage (20<Udepl<60V)
- bias & interstrip resistances    (1<Rbias<10 Mohm; Rinter~GOhm)
- coupling capacitors (15pF/cm)
- search for shorted capacitors  (breakdown >100V/50V for p/n-side)
- allow totally 2% bad strips on each side
- Problems  - Micron delivery of 90o detectors, Eurisys sensors for F-wedges

## Ladder (Hybrid-) Design

- Barrels:
- active (cooled) and passive Beryllium support and bulkheads
- operation temperature ~5-10 0C
- ladder alignment using machined posts/notches on bulkheads/ladders
- ladder placement accurate to 20m and measured to <5m (ZEISS CMM)
- barrel/disk geometry with 2mm gap forces   to move electronics and cables inboard
- flexible HDI tails

## High Density Interconnect (HDI)

- 912 HDIs needed with 6,192 SVX2e chips
- Kapton based flex circuits, double sided with 0.2 mm pitch, for chip mounting (SVX2e)
- Barrels/Disk geometry requires 9 types  (3 differ only in pigtail length)
- Fabrication:
- visual inspection
- Lamination to Be Substrate
- Component, Chip mounting at Promex, Silitronics
- Testing, Burn-in, and encapsulation

- H-disk HDI 6-chip

- 9-chip barrel HDI

## HDI fabrication problems

-  F-wedges have a kapton flexible pitch adapter for the n-side (50). Max Levy had problems making bondable units.     Solved by not using cover layer.
- Bubbling of flex during surface mount at Promex. Solved by more careful QC and new vendor Silitronics.
- Wire bonding pull strengths on some substrates.  Solved at Silitronics, still a worry at Promex.
- Needed to reorder all parts due to large preproduction runs and low production yields, this slowed the schedule down.
- Constant QC problems at Promex and they lost parts.

## Ladder/Wedge Production

- Done at Fermilab
- Fixtures are ready and working
- Double sided ladder production is a multistep process spread over 3 days mostly due to epoxy hardening time
- 1.5 million bonds to do for detector at FNAL - Use KS 8090 bonder 5 wires/sec, small step size (better than 70)

- F wedge gluing fixture

- 8090 bonder

## Ladder Fabrication 

- Aligning silicon
- on fixture

- Gluing HDI

- Allowing to cure
- under weight

## Ladder Fabrication

- Bonding, use automatic 8090 machine as well
- as 1478

- Gluing rails and
- Be-substrate

- Flip over and glue
- HDI on n-side

## Assembly of Full H-Wedge 

- Full wedge is made of two half wedges glued together. It makes a double sided device with  a stereo angle of 15 degrees.
- Assembly is made on a bifacial machine with two microscopes.Typical accuracy 5 -10 ****. Two wedges per day can be made.

**Upper microscope**

**Lower Microscope**

**Assembled wedge**

## Ladder/Wedge Testing

- Pluck dead or noisy channel bonds until leakage current is OK (<20uA) with detector under bias voltage.
- Run detector burn-in for 48 hours           each channel is calibrated for gain and noise
- Laser test detector                                  shine laser on sensor and measure charge collection and readout capabilities of each channel
- Grade electrical quality of detector         <3% dead or noisy channels  - A           3-5%    “            “       “          - B

## D0 Silicon Readout Scheme

- Fiber

- receiver

- Fiber

- Driver

- VRB

- VRBC

- D0 Clock

- System

- Trigger

- Manager

- Sequencer Cd

- (platform)

- VME

- Fiber Optic

- Links

- pigtail

- low mass

- cable

- high mass cable

- VBD

- high mass cable

## Data Acquisition

- Provide adequate operating margin for device
- Ensure adequate diagnostics tools and controls
- Exercise control logic
- Exercise Data Acquisition and filtering scheme
- Exercise offline software

- Commission read out electronics in phases “on the bench” without detectors attached
- Integrate final components as soon as available
- Read out small scale setup in final configuration
- Enlarge scope of read out

- Goals

- Timeline

## Low Mass Cable

-  5 mil pitch traces up to 110 inches long
-  made at Kansas City DOE production
-       laboratory
-  in production, 100 long (110”) being tested
-       912 needed

## Interface Card

-  Refreshes signals and adjusts timing
-  Manages SVX2e power and timed turnon
-  Monitors SVX2e voltage, current and temp
-  Distributes bias voltage

- Status - version 2 in production, first version
-      used to debug problems

- 9U
- VME
- card

## Control and Monitoring

- All slow controls and monitoring uses 1553 protocol with interface board
- In testing and debugging stage

**Detector**

**Readout Crate**

**Controls Crate**

*UNIX Hosts*

*Control Room PCs*

**EPICS Clients:**
**  ****SVX Download**
**  ****Low Voltage**
**  ****High Voltage**
**  ****1553 Devices**
**  ****Rack Monitor**

*Controls*

*Ethernet*

***1553***

## Data Acquisition

- All pieces to exercise full data acquisition chain are in place
- Read out to L3 system extensively tested
- Online Examine SMT analysis code tested on raw data

## Endview of Barrel/Disk

-  Assembly

- Carbon fiber support
- half cylinder

- Cooling manifolds

- Be bulkhead

## Barrel Assembly

- Beryllium Bulkhead parts all ready
- 1st barrel being assembled now

- We are trying to understand alignment precision and constraints and implications of flatness problem in Z on 3-chip ladders

## Disk Assembly

- Beryllium Rings for F-disks and H-disks all parts all ready
- Procedures being developed for alignment

- 1st F-disk being assembled on CMM

## Cooling

*Two redundant chillers, each providing 4400 watts **refrigeration at -10**o**C*
*Coolant = 30% ethylene glycol in water*
*System has been conservatively sized assuming**5 milliwatts power per channel (4 kW total)**(actual dissipation is about 4 milliwatts/channel)*
*Pressure at detector supply manifolds ~ 14 psia *
*Pressure drop across detector elements ~ 5 psi at -10**o**C*
*Temperature rise across detector elements ~ 1.0-1.5**o**C*

## COSMIC TEST LADDER

**COSMIC TEST LADDER**
** ****Configuration**

-  The coordinate system is defined by 3 and 9 o’clock holes in cooled  BH
-  There are seven ladders installed so far as marked on the drawing
-  This setup is used to study system integration and alignment issues using the spare Be bulkhead

**12-3SS-L**

**13-3SS-L**

**14-3SS-L**

**17-3SS-L**

**9131**

**9132**

**6105**

- 3 o’clock

- 9 o’clock

## Production Status

- TOTAL   55        42          111           37        156
- Needed    72       144         216          144       192

- We are about 50% through production
- parts delivery has been limiting throughput

- Ladders/Wedges through wire-bonding per month

## Schedule 

- Part delivery and lower yields have slowed production schedule
- Testing of detectors is a bottleneck right now
- Because of schedule worries, contingency has been obtained by

- Changing pit installation schedule
- Splitting the carbon-fiber half support
-       cylinder so that the detector can
-       be mounted in 2 halves
- This has gained 3 months!

## Production Status

- 6-chip: 5/week!

## Schedule

- New Schedule adopted based on split support cylinder:
- First half cylinder by August 1
- Second half cylinder by November 1

## Conclusions

- Sensor Delivery on track except for 90o detectors where we will have to accept lower quality to meet schedule
- Production proceeding, but we need to ramp up the rate
- System integration tests proceeding, but we still have a long way to go!
- Barrel/Disk Assembly has started

- We still think we can make our deadlines, but it is going to be tough going!
- We’re looking forward to data in 2001!

## F Disk

*Silicon IR = 26 mm, OR = 105.27 mm at wedge centerline*
*Readout mounts outboard of silicon, which allows disk to **fit within a gap of 8 mm*
*Wedges alternate between two surfaces of a central**cooling/support channel (beryllium)*
*Effective stereo angle = 30 degrees*
*p-side Trace angle = -15**o** with respect to wedge centerline**Pitch = 50 μm*
*n-side Trace angle = +15**o** with respect to wedge centerline**Pitch = 62.5 μm*

## H DISK

*Silicon IR = 94.5 mm, OR = 236 mm at wedge centerline*
*Readout mounts on outer silicon detector*
*Wedges alternate between two surfaces of a central **cooling/support channel*
*Effective stereo angle = 15**o** *

## Scheme of Bifacial Machine

- Upper camera

- Lower Camera

- Accurate alignment of two cameras in angle and X-Y positions required

## D0 Detector Area

**VRB **
**Controller**

**Optical Link**
**1Gb/s **

**3/6/8/9 Chips**

**Sensor**

**V****B****D**

**V****R****B**

**V****R****B**

**V****R****B**

**V****R****B**

**68k**

**Secondary Datapath**

**VME**

**Low Mass**

**3M**

**1**
**5**
**5**
**3**

**NRZ / CLK**

**SVX  EMULATOR**

**IB**

**Monitoring Control**

**L3**

**HOST**

**Examine**

- Concurrent with work at the silicon facility, a complete shake down of the read out system will take place at the assembly hall of final read out configuration downstream from the interface board, including online data checking (Examine).

## VME System Tests

- 	System equivalent of ~22,000 channels
- 	Data transfer on VME at ~ 12 Mbytes/s

- Very low noise on data transfer backplane
- Proper handshaking between read out elements
- Data integrity > 1013			                   (~ 1 non-fatal error every ~30 minutes)

- Ran with single chain (hdi) in close to final configuration, including low mass cable, 30’ 3M/50 conductor cable. Optimized impedance matching for data and control lines on sending and receiving ends

- Successfully operated all hdi types
- Mapped out operating margin for all hdi types
- Data integrity > 1013  for all hdi types with comfortable operating margin

- Written raw data to disk, unpacked and analyzed “offline” within L3 framework and online monitoring program (Examine)