The D Fiber Tracker

1
The DØ Fiber Tracker
Gregory A. Davis University of Rochester
AND GEORGE GINTHER

• APS Meeting April 2002

2
DØ A Sense of Scale
The Central Fiber Tracker (CFT)
DØ
Todays Speaker
15 story building
DØ
3
DØ
4
CFTs Place in DØ

• Scintillating fibers are 1.8 or 2.6 m long
• Waveguides are from 8.2 to 11.4 m long
• On the order of 10 photons will get to the VLPCs
• Fiber Diameter 0.835 mm
• CFT 77k channels
• PS 23k channels

5
A Single Channel
The Central Fiber Tracker (CFT)
The Preshowers Central (CPS) and Forward (FPS)
6
The Amazing VLPC
Visible Light Photon Counter (VLPC)

• Operate at 9 K
• Quantum Efficiency 80
• Operate at high rates
• High gain 17k to 65k electrons per detected
  photon

7
Resolution
Below Ratio of calorimeter energy (E) and track
momentum (P) for electrons
DCA Distance of Closest Approach
Above DØs position resolution is improved from
100 ?m to 48 ?m when the CFT is used with the
silicon.
8
Light Yield by Layer and ?
9
A Z ? ee Candidate
A Candidate Z -gt ee event Mass 89.9 GeV/c2
10
Conclusion

• In Tevatron Run II, DØ uses a scintillating fiber
  tracker.
• The tracker has shown beautiful tracks in real
  events.
• Our performance is improving as we commission the
  detector.
• The VLPCs used in the tracker could have
  widespread use in future detectors of various
  sorts, including but not limited to scintillating
  fiber trackers and preshowers.
• The DØ fiber tracker has a bright future for the
  remainder of Tevatron run II and could inspire
  future detectors as well.