The BTeVTracking Systems

David Christian

Fermilabf

January 11, 2001

BTeV in C0

David Christian p2The BTeV Tracking Systems

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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

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Types of tracking detectors

The BTeV Tracking Systems

Pixels provide “space point”measurements

Strip detectors and straw tube chambersprovide “projective” measurements

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

Relatively fewer active elements-electronics may be located at

the edges of the detectors.

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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)

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•Near the beam pipe, the density of tracks is toohigh 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

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•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 ActivitiesFrom 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

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

10 cm

The BTeV Tracking Systems

Pixel Readout Chip

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FPIX1

•Different problem than LHC pixels:132 ns crossing time (vs. 25ns) easierVery 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) inwhich resolution <9 was demonstrated.

•New “deep submicron” radiationhard design (FPIX2):Three test chipdesigns 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

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

Micrograph of FPIX1: bump bonds are visible

The BTeV Tracking Systems

Sensor

Readout chip

HDI

HDI

Sensor(5 readout chips underneath)

Wire bonds

Tracking Systems R&D Status

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•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 andconstruction techniques.– Expect to benefit greatly from sensor development done for LHCand from Fermilab experience (CDF & D0 - SiDet).

The BTeV Tracking Systems