Indiana University
Optical Fiber Waveguides
The D0
Upgrade detector has several systems relying on particle detection
on interactions resulting in small amounts of light either in scintillating
fibers (the central fiber tracker, CFT) or bars of scintillator with a
wavelength-shifting fiber shot down the center (central and forward preshower
detectors, CPS and FPS). From the detector, the light is carried more than
10 meters to a readout system located below the detector.
Each 9-14 meters long, containing 256 clear, multiclad optical fibers
terminated on one end with two 128-fiber optical connectors that mate into
the cassettes containing the visible light photon counters (VLPC's) that
convert light signals into electrical signals. The VLPC's are devices with
quantum efficiencies of ~80% and gains of ~50,000. However, they have to
be run at ~10 degrees K in a large liquid helium cryostat, necessitating
their location relatively far from the subdetectors. On the subdetector
end, of the waveguide, there are three types of connectors depending on
which subdetector the waveguide is reading out.
-
Central
Fiber Tracker: single curved optical connector with two singlet layers
of 128 fibers each. Mates into a similar connector on the ends of the 8
carbon fiber cylinders to which the scintillating fibers are mounted (axially
and at a small stereo angle). These are currently being made in Notre Dame.
-
Central Preshower Detector: the 256 fibers branch out into 16 pigtails
each containing 16 fibers which terminate into a CPS detector connector
that mate into similar connectors with wavelength-shifting fibers at the
end of the three (one axial, two stereo) thin barrels of the CPS. Have
been constructed at Indiana University.
-
Forward Preshower Detector: as for
the CPS, with slightly different optical connectors and longer. Tooling
up to start making these waveguides.
People
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DAQ and testing equipment
-
Graduate student Dayong Liu
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Graduate student Felix Liu
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Undergraduate student Bernard Voos
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Undergarduate student Matt Evans
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Undergraduate student Mike Bates
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Waveguide prototyping and assembly
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Full-time technician Debbie Hamm
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Undergraduate student Erica Raffauf
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Undergraduate student Dan Langley
Waveguide Testing Equipment
From talks:
Central Preshower Waveguides
CPS Waveguide Status, Dec. 1999, talk (postscript files of text
pages)
Forward Preshower Waveguides
Overall Mapping
-
The "Synapse"
Page
-
Fred
B's master mapping page
-
View of the North face of the CFT and CPS detectors showing the ribbon
and clear fiber wave guide bundle locations. [pdf]
[ps]
-
View of the South face, as above ... [pdf]
[ps]
-
Overhead view of the EAST cassette cryostat. [pdf]
[ps]
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Overhead view of the WEST cassette cryostat. [pdf]
[ps]
Light
Transmission Tests
For Abid, some slides
for presentation
-
Cover/CPS waveguide status (pdf)
(ps)
-
Schematic showing location and pigtails affected by detector foot plate
interference (pdf)
(ps)
-
FPS Status 1 (pdf)
(ps)
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FPS Waveguide Cassette-end and bifurcation assembly schematic (pdf)
(ps)
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FPS Waveguide Detector-end bifurcation and pigtail assembly schematic (pdf)
(ps)
-
FPS mapper program screen shot (pdf)
(ps)
-
FPS Status 2 (pdf)
(ps)
Rick Van Kooten
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Last
modified: 2 Aug. 2000