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Commissioning Results of the D Tracking System

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Require good 3D track reconstruction performance for high-pT (top, Higgs, ... A cylinder of 3 barrels and 6 F disks was inserted into each end of the CFT bore ... – PowerPoint PPT presentation

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Title: Commissioning Results of the D Tracking System


1
Commissioning Results of the DØ Tracking System
  • Design
  • Installation and Commissioning
  • Tracking/Vertexing Results
  • Harald Fox
  • Northwestern University
  • May 24, 2002

2
The Fermilab Tevatron Collider
3
The DØ Detector
antiprotons
4
Tracker Design
5
SMT Design
12 F Disks
4 H Disks
6 Barrels
  • 4-layer barrel cross-section

6
SMT Design
  • Require good 3D track reconstruction performance
    for high-pT (top, Higgs, EW, NP) and low-pT (B)
    tracks out to ? lt 3
  • Momentum resolution less than 10 at pT 1 GeV/c
  • Impact parameter resolution within 30 ?m
  • Forward H disks are employed to achieve these
    resolutions at high ?

7
SMT Readout Electronics
  • Interface Boards
  • Refresh signals and adjust timing
  • Power management and monitoring
  • SEQencers
  • Management of SVX
  • Conversion to fiber optics
  • VRB (VME Readout Buffer)
  • Data buffer pending L2 trigger decision
  • 50 Mb/s/channel
  • 5-10 kHz L1 accept
  • ?1 kHz L2 accept rate
  • SVX IIe Chip
  • 128 channel, 32 pipeline cells
  • 8 bit ADC with sparsification
  • 106 MHz digitization, 53 MHz readout
  • Radiation hard
  • Developed by LBL/Fermilab group

8
CFT Design
  • 8 layers of axial and 3 stereo fibers mounted on
    carbon fiber support cylinders.
  • 20cm lt r lt 51cm.
  • 76,800 individual fibers.
  • Diameter 835µm. Length 1.8/2.6m.
  • The interlocked fibers are precisely positioned.
  • Hit resolution about 100µm.

9
CFT Readout Electronics
  • 8-11m long wave-guides to Visible Light Photon
    Counter (VLPC, solid state photo multiplier).
  • VLPCs are operated at 9K. Quantum efficiency
    80.
  • 1 mip 8 photo electrons ? Excellent S/N!
  • High gain 17k 65k e per photon
  • AFE boards provide
  • Bias voltage
  • Temperature control
  • Fast digital trigger information
  • Analog pulse information (SVX)
  • SEQ VRB readout as SMT

10
Installation
  • Fiber tracker installation
  • 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
  • Axial Fiber Tracker electronics installed in
    November 2001
  • Stereo electronics completed April 2002

SMT cylinder
Interface Boards
Low Mass Cables
High Mass Cables
SMT
Calorimeter
Cryostat with AFE boards
Wave guides
11
SMT Charge Collection
  • Cluster charge (corrected for track angle) 1 mip
    25 ADC counts. Noise lt 2ADC counts.
  • Charge correlation between p- and n-side of a
    detector

fL 4.5
  • Lorentz angle The charge deflection due to the
    magnetic field

12
CFT Commissioning
Z?ee candidate event. Mass 89.9GeV/c2
Light yield per sector vs pseudorapidity ?
13
Tracking and Vertexing
CFT-SMT track matching
Impact parameter resolution
Vertex measurements
DCA
14
Physics Results
E/p for W?e? candidates
KS ? pp- cand.
Z ? µµ- cand.
J/? ? µµ- candidates
First evidence for B decays
15
Conclusions
  • Design
  • The DØ tracking detectors are designed to have a
    good impact parameter resolution over a wide
    range of ?.
  • Commissioning
  • The SMT was the first major DØ Upgrade detector
    system fully operational for Run 2A.
  • About 95 of the channels are available for
    readout.
  • Results
  • Calibration, beam measurement, and alignment
    results are looking promising.
  • Physics results coming in.
  • Noise studies, tracking refinements, etc.
    continue.

16
The work of many people...thanks to all of
them.
The DØ Collaboration
17
Lorentz angle
P-side (axial)
Phi distribution for one strip clusters
h
e-
  • Lorentz angle is different for p- and n-sides
  • Lorentz shift is not visible for 90 deg stereo
    strips
  • Lorentz shift is large for 2 deg stereo
  • Lorentz angle can be measured in local phi
    distribution for one strip clusters
  • Measurement is NOT affected by alignment or
    reconstruction

Data p-side
18
SMT Design Stereo Angles
  • Ladders
  • 3-chip 72 single-sided, axial ladders in the two
    outer barrels
  • 6-chip 144 double-sided, axial/90 ladders in
    the four inner barrels
  • 9-chip 216 double-sided, axial/2 ladders in all
    barrels
  • Wedges
  • F Disks 144 double-sided, 15, 68 chip wedges
  • H Disks 962 back-to-back single-sided, 7.5, 6
    chip wedges

9-chip ladder
H wedge
19
Production Assembly Testing
  • Probe 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 has been
    mounted.

V-max
Fail
20
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
68k/PwrPC
1 5 5 3
VRB Controller
Bit3
VME
PC
L3
MPM
Counting House
SDAQ
21
Alignment Residuals
  • SMT-only tracking with at least 4 hits
  • Magnet off data
  • Similarity of residuals from reconstruction with
    ideal and survey geometries indicates excellent
    internal alignment of the SMT

Ideal Geometry
Survey Geometry
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