# Presentation: 020692

## The new Silicon detector at RunIIb

**What’s new?**
-  Data will be collected from 5 to 15 fb-1 at s=1.96 TeV
-  Instantaneous luminosity will increase up to L=5X1032 cm-2s-1
-  Average number of interactions per bunch crossing will be    15 at 396 ns
-    (peak luminosity)

**The new Silicon detector at ****RunIIb**

**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 CDF Run IIb Silicon Detector**

**        ****Physics program**** ****at RunIIb**
**Estimated useful lifetime of the inner layers of the Run IIa silicon detector is ~ 4 fb****-1**
**Full Run II(a+b) luminosity will be 5-15 fb****-1**
**To fully exploit the potential of the Tevatron, the inner 6 layers of the RunIIa silicon system will be replaced with an new design**
**Outer 2 layers of Silicon – the ISL- will be retained for Run IIb**

- The physics goals of RunIIb are broad and fundamental:
-  Tevatron is the world’s 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**

- in the range 80 < mH < 120 GeV the Higgs mainly decay into b-bbar   . This gives the signature of 2 jets.

- Significance of a potential Higgs discovery: ****** ******** L* ********2****  **with  =the b-jets tagging efficiency, L=luminosity.

** ****  ****The new silicon detector layout**

- Plot is Higgs mass sensitivity as a function of b-tag efficiency  ( is relative to 65%)

- 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

**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 **

- 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)

- Sensor pitch is 25 um, readout pitch=50um.  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.

**Inner Layer Design**

**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.

- Layer 0: 12 fold Axial
- Layer 1: 6  fold Axial-Axial
- Layer 2: 12 fold  Axial-SAS(1.2)
- Layer 3: 18 fold SAS(1.2)-Axial
- Layer 4: 24 fold SAS(1.2)-Axial
- Layer 5: 30 fold Axial-Axial

- 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.

**Sensors**

**Cables**

**Hybrids**

**Sensors**

**Hybrids**