Tevatron II: the world

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The CDF Run IIb Silicon Detector
The new Silicon detector at RunIIb

• Tevatron II the worlds highest energy collider
• Whats new?
• Data will be collected from 5 to 15 fb-1 at
  ?s1.96 TeV
• Instantaneous luminosity will increase up to
  L5X1032 cm-2s-1
• Average number of interactions per bunch
  crossing will be 15 at 396 ns
• (peak luminosity)

What is the goal? The Fermilab collider program
has the potential for revolutionizing our
understanding of elementary particle physics. The
combination of the upgrade of the Tevatron
complex and the greatly improved detectors
provides extraordinary opportunities for discovery
The new silicon detector layout

• Physics program at RunIIb

The new detector SVXIIB has 6 layers with 2
barrels in z, each 66cm long. As in RunIIa, the
staves within a layer are arranged in a
castellated pattern. Unlike Run IIa, single
sided silicon sensors are used. Each stave has 6
sensors glued on each side. Layers 1 and 5 have
axial sensors on both sides to provide redundancy
at the innermost layers and to provide a better
connection to the outer trackers. Layers 2,3,4
have axial sensors on one side and small angle
stereo sensors (SAS) on the other side. The
innermost layer, Layer 0, has one layer of single
sided sensors (similar to the Run IIa Layer 00)
glued to a separate carbon fiber structure which
is supported by the outer barrel.

• The physics goals of RunIIb are broad and
  fundamental
• Tevatron is the worlds only source of top
  quarks the top seems to be uniquely connected to
  the mechanism of mass generation
• Tevatron can uniquely access the BS meson its
  mixing rate can determine the length of one of
  the sides of the unitary triangle
• Tevatron will experimentally test the new idea
  that gravity may propagate in more than 4dim of
• space-time
• Search for light boson Higgs

Hybrids
Sensors
Layer 0 12 fold Axial Layer 1 6 fold
Axial-Axial Layer 2 12 fold Axial-SAS(1.2?) Laye
r 3 18 fold SAS(1.2?)-Axial Layer 4 24 fold
SAS(1.2?)-Axial Layer 5 30 fold Axial-Axial
in the range 80 lt mH lt 120 GeV the Higgs mainly
decay into b-bbar . This gives the signature of
2 jets.
Outer Barrel Design Sensor pitches are 37.5 um
(Axial) and 40 um (SAS). Alternate strips are
read out. A 4-chip hybrid is glued to each
sensors pair and is bonded to a bus cable
passing beneath the sensors. The stave core is a
carbon fiber foam sandwich with embedded cooling
tubes.

• Significance of a potential Higgs discovery s ?
  L ?2 with ? the b-jets tagging efficiency,
  Lluminosity.

Hybrids
Inner Layer Design
Sensor pitch is 25 um, readout pitch50um. Two
sensors are bonded together to form a single
readout unit. Fine pitch cables connect the
sensors to the hybrids (2-chip). The hybrids and
the associated cooling are outside the tracking
volume. The longest cable is 60 cm. Sensors are
cooled by coaxial tubes in the carbon fiber
support structure.
Cables
Sensors
Plot is Higgs mass sensitivity as a function of
b-tag efficiency ? (? is relative to 65)
As in Run IIa, a support cylinder made of
Carbon Fiber and a honey comb material will
support the barrels between the mount points at
the ends of the ISL detector (2m apart)

• Project Status and Schedule
• Successful DOE Lehman Review Sept. 2002
• Total Silicon project cost 18 million
• Ready to install May 31, 2006, with 33 weeks
  contingency
• 12 prototype modules and 3 prototype staves
  assembled
• Modules and Staves are being tested with the
  full RunIIb DAQ system
• Summer 2003
• Preproduction SVX4 chips arrive May 2003
• Preproduction hybrids arrive July 2003
• Production Sensor Delivery June 03 March 04
• Stave Production February 04 - December 04
• Ready to install September 05
• Schedule contingency from Sept. 05 May 06.
• Shutdown for installation 8 months

• Improvements in Run IIb Design
• Radiation hard readout chips (0.25 micron
  technology)
• Extension of the contained b-jets region
  (active length 1.2 m vs 0.9m in Run IIa)
• larger and more uniform radial distribution (R
  2.1 16.6 cm compared to 1.3-10.6cm in Run IIa)
• Good impact parameter resolution with low mass L0
  design
• Strengthened inner tracking - redundant axial
  layers at L1
• Larger radius outer staves - better connection to
  ISL
• Fewer component parts 4-chip hybrids used on 93
  of total