# Presentation: 112818

## f

- Tracking Systems

- David Christian
- Fermilab

- January 11, 2001

## BTeV in C0

- David Christian	p2

- The BTeV Tracking Systems

- 0

- 12 m

- p

- Dipole

- EM     Cal

- Hadron    Absorber

- Muon    Toroid

- ± 300   mrad

- Magnet

**Silicon pixel vertex detector** provides:
- Pattern recognition power
- Very good position resolution (~7
- Radiation hardness

**Forward tracker** provides:
- Momentum measurement
- Pattern recognition for tracks born in decays
-   downstream of vertex detector
- Projection of tracks into particle ID devices

## Types of tracking detectors

- David Christian	p3

**Types of tracking detectors**

- The BTeV Tracking Systems

- Pixels provide “space point”
- measurements

- Strip detectors and straw tube chambers
- provide “projective” measurements

- Very large number of active elements
- electronics must be distributed in
- the active area of the detectors.

- Relatively fewer active elements
- electronics may be located at
- the edges of the detectors.

## Forward Tracker

- David Christian	p4

**Forward Tracker**

- The BTeV Tracking Systems

- Forward tracker consists of:
- Straw chambers
- Cost effective solution for large area coverage
- High segmentation (baseline=4mm diameter straws)
- Can “clamshell” around beam pipe without a heavy frame
-   in the active area
- Robust: a broken wire does not kill an entire plane
- Short drift times (single crossing memory time)
- Good precision  good momentum, mass resolution
- Silicon strip detectors
- 100 m pitch  low occupancy, even near the beam pipe
- More radiation hard than straws

## Silicon Strip Detectors (SSD’s)

- David Christian	p5

- Near the beam pipe, the density of tracks is too
- high for straws to handle (occupancy, radiation damage)
- Central 24 cm x 24 cm will be covered with SSD’s
-   (central hole for the beam pipe)
- 6 stations per spectrometer arm; 3 views per station
-  100 m pitch; 108000 readout channels
- “CMS style” single sided p-on-n sensors
- Planar geometry – easier than barrel

- The BTeV Tracking Systems

## Straw Chamber – Baseline Design

**Straw Chamber – Baseline Design**

- David Christian	p6

- 4mm diameter straws
- Wire readout at both ends
- (glass bead at center)
- 3 layers per view
- 3 views per station
- ~66000 straws in total

- ATLAS straw cutter

- The BTeV Tracking Systems

## Straw Activities

- From visit to Indiana University –
- Rob Gardner, Dave Rust – to see
- ATLAS straw production facility

- Test stand at Lab 6

- Close-up of UC Davis/FOCUS
-  straw chamber

- p7

## Pixels – Close up of 3/31 stations

**Pixels – Close up of 3/31 stations**

- David Christian	p8

- 50m x 400m pixels
- Two pixel planes per station
- (supported on a single substrate)
- Detectors in vacuum
- Half planes move together when Tevatron
- beams are stable.

- 10 cm

- The BTeV Tracking Systems

## Pixel Readout Chip

- David Christian	p9

- FPIX1

- Different problem than LHC pixels:
- 132 ns crossing time (vs. 25ns)  easier
- Very fast readout required  harder
- R&D started in 1997
- Two generations of prototype chips
- (FPIX0 & FPIX1) have been designed
- & tested, with & without sensors,
- including a beam test (1999) in
- which resolution <9 was demonstrated.
- New “deep submicron” radiation
- hard design (FPIX2):Three test chip
- designs have been produced & tested.
- Expect to submit the final design
- ~Dec. 2001

- The BTeV Tracking Systems

- A pixel

- 7.2 mm

- Test outputs

- 8 mm

- Readout

## Pixel detectors are hybrid assemblies

- David Christian	p10

- Sensors & readout “bump bonded” to one another.
- Readout chip is wire bonded
- to a “high density interconnect”
- which carries bias voltages,
- control signals, and output data.

- Micrograph of FPIX1: bump bonds are visible

- The BTeV Tracking Systems

## Tracking Systems R&D Status

- David Christian	p11

- Pixel detector component-level R&D is quite advanced
-  – focus now shifting to system design, including low mass
-     support & cooling structure, vacuum vessel, & motion control.
- (Fermilab, Syracuse, Iowa)
- Straw detector R&D activities have begun.
- – Lab 6 test stand working.
- – Prototype detector (96 straws) to be built in 2001.
- (Fermilab, S.M.U., U.C. Davis, Indiana U.)
- Silicon Strip Detector R&D is being led by University groups
-  (Milano, Tennessee, Colorado).
- – Readout chip development starting in Milano.
- – Balance of effort is concentrating on system design and
- construction techniques.
- – Expect to benefit greatly from sensor development done for LHC
- and from Fermilab experience (CDF & D0 - SiDet).

- The BTeV Tracking Systems