The BTeV Tracking Systems David Christian Fermilab f January 11, 2001

BTeV in C0 David Christianp2 The BTeV Tracking Systems 0 12 m p p Dipole RICH 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

David Christianp3 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.

David Christianp4 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 Christianp5 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; readout channels “CMS style” single sided p-on-n sensors Planar geometry – easier than barrel The BTeV Tracking Systems

Straw Chamber – Baseline Design David Christianp6 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 David Christianp8 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 Christianp9 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 The BTeV Tracking Systems A pixel 7.2 mm Test outputs 8 mm Readout

Pixel detectors are hybrid assemblies David Christianp10 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 Sensor Readout chip HDI Sensor (5 readout chips underneath) Wire bonds

Tracking Systems R&D Status David Christianp11 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 (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