Commissioning, operation and first physics results of the CDF Run2a Silicon and

CDF

G. Bolla, Purdue University for the CDF RUN2 SiliconEPS (July 17th-23rd 2003), Aachen, Germany

Commissioning, operation and first physics results of the CDF Run2a Silicon

and status of its future upgrade for Run2b

Gino BollaPurdue University

ForCDF RUN2 Silicon Group

CDF


CDF RunII (The need for a strong tracker)

Physics with 2-9 fb-1Precise Measurements

of Mtop and MW

CP violation, Bs mixingMore …

B,C quarks tagging is crucialLong lifetime (mm to

cm) Vertex finding

High impact parameter resolution

Efficient triggerSVT (secondary Vertex

Trigger)Fast (@L2) displaced

tracks trigger.

COT30240 ch, 96 layer drift chamber(1/pT) ~ 0.1%/GeV(hit) ~ 150m

SVXII + ISL + L007-8 silicon layers722000 chr, rz viewsz0

max=45 cm, max=21.3<R<30cm

CDF


A top candidate

Typical travel distances:Bottom: 5 mmCharm: 1 mm

Impact parameter resolution~35 m in Will improve by

using L00

CDF


CDF Silicon (What does it look like)

• 1 layer (L00) very close to the beam: improve IP res. & b-tagging

Use L00/SVXII for vertexing & trigger: high density & precise alignment crucial!

Use ISL for tracking: simpler design; precise alignment not so important

x [cm]

y [

cm]

HIGHLIGHTS:

•High speed

•Dead-timeless operation

•Displaced track trigger

L00ISL

SVXII

•1 central / 2 forward layers (ISL) at large radius: tracking

•5 layers (SVXII) very compact in r,,z: 3D vertexing & tracking

CDF


6 electrical barrels

Z

SVXII the center piece

5 double sided layers 3 x 90o and 2 x 1.2o

Very compact Tight alignment tolerances

For the trigger Very symmetric Many (maybe too many) different

components

2.5 cm

10.6 cm

x

y

Note “wedge” symmetry

CDF


ISL on the outside and L00 on the inside

One central layerLink tracks from COT to SVXII

Two forward layers (~2 m long)Extend tracking up to ||=2 (COT stops at 1)

Simpler designNot used on the trigger (relaxed alignment)Hybrids mounted OFF siliconA single flavorLot of space (compared to SVXII)

lightweight signal & bias cables (Kapton)

sensors

cooling tube

SVXII inner bore

2.3cm4.2cm Be beampipe

Precision position measurement before scatteringOne SS layer on the Beam pipe

25 m pitch (50 m readout)Low material budget

High RadiationActively cooled LHC-like sensorsElectronic at larger radii

ISL L00

CDF


The heart of it all (the SVX3d chip)

128 channels

46

pip

el in

e c

ell s

Fabricated in the Honeywell 0.8m rad.hard process

Analog Front End (FE) and Digital Back End (BE):- Compatible with 396/132

nsec bunch spacing

- FE has relatively low noise integrator with 128 channels and 46 cell analog pipeline with 4 buffer cells

- BE has comparator, 8-bit Wilkinson ADC, and sparse readout with neighbors logic

Dead-timeless: Capable of analog

operations during digitization and readout

Dynamic pedestal subtraction:- Enables on-chip common

mode noise suppression

CDF


Same data but different code

Integration and Commissioning

0%

20%

40%

60%

80%

100%

Ap

r-01

Oct-01

Ap

r-02

Oct-02

Ap

r-03

SVX

ISL

L00

A long list of troubles to deal with Most of them specific to the CDF system Others are of common interest

A good monitoring strategy First look at the whole thing as a piece of

hardware Second look at it as a particle detector

Now 90+% is producing good data for physics

Large effort on the offline as well Clustering Alignment Tracking algorithms

Wire-bonds with current in the 100 mA range if pulsed at the right frequency can oscillate due to small (10-50 mg) Lorentz forces because resonance behaviors can be excited. Fatigue induces cracks on the heel and the electrical continuity is lost

CDF


Performance (1)

resolution

9m

Residual [m]

Charge [ADC]

charge collection

z s

ide c

harg

e

[AD

C]

side charge [ADC]

charge correlation

Single hit Efficiencies~99 %

S/N >10

dE/dx particle identification

CDF


Performance (2)

• Measurements using triggered J/Psi candidate events since January 2003 shutdown.

• No background subtraction is performed. • A further 3 % increase on efficiency is expected

• Performing a background subtraction (about 1%). • Improvements of ISL alignment and retuning of the the tracking

road sizes (about 2 %)Average tracking Efficiency is 87.8 ± 0.1 (stat)%

Average fake rate is 1.7 ± 0.4 (stat)%

CDF


Performance (3)

At a higher level things get more complicated B-tagging efficiencies in the 40-50 %

Visible degradation of performances in the regions between barrels

Will improve in the future Adding L00 will help in between barrels coverage will increase by using ISL

Lots of CDF physics talks at this conference

CDF


SVT (Secondary Vertex Trigger)

Input (L1A ~10-40 KHz)Outer drift chamber trajectoriesSilicon pulse height for each channel

Output (~ 20 s later)Trajectories that use silicon hits

150 VME boardsFind and fit silicon tracks with ~ offline

accuracy In 15 microseconds

look for 2 tracks with impact parameters > 120

m

primary vertexsecondary vertex

impact parametera few mm

2.5 MHz

25 kHz

250 Hz

50 Hz

L1: 5.5s, synchronous, fast programmable logic (CAL, , COT tracks)

L2: ~30s, asynchronous, programmable logic + CPU (jets, silicon tracking)

L3: ~200 PCs spend ~1s/event on ~full reco (full-precision tracking, form masses, etc.)

~140 separate trigger paths (e, , , , , jet, displaced track, b-jet, …)

CDF


SVT performance

-500 -250 0 250 500SVT impact parameter (m)

35m 33mresol beam = 48m

0 10 20 30 40 50

SVT latency (s)

24 s

0 2

+500

-500

0

d (m) vs (raw)

d (m) vs (subtracted)+500

-500

0

CDF


A paper with only 12 pb-1

Results: M(Ds) – M(D+) 99.41 + 0.38 + 0.21 MeV/c2

PDG: 99.2+0.5 MeV/c2

CDF


What is there ahead of us

Until the LHC turn-on, the Fermilab Tevatron has the highest energy collisions and is the only place to search for the Higgs and other new particles.

The Run II Physics Program extends to 5-15 fb-1.

Expected life of the Run IIa Silicon detector ~ 4-5 fb-1 .

Run IIb Silicon Detector replaces the inner 6 layers with an improved and radiation tolerant detector.

Need to be built in a very tight schedule

CDF


The CDF Run2b Silicon

Layer 0: 12 fold AxialLayer 1: 6 fold Axial-AxialLayer 2: 12 fold Axial-Stereo (1.2o)Layer 3: 18 fold Axial-Stereo (1.2o)Layer 4: 24 fold Axial-Stereo (1.2o)Layer 5: 30 fold Axial–Axial

Improvements in RunIIb Design:

Rad hard RO chips (0.25m technology)

• Extension of the “contained b-jets” region (active length = 1.2 m vs 0.9m in RunIIa)

• larger and more uniform radial distribution (R= 2.1 – 16.4 cm compared to 1.3-10.6cm in RunIIa)

• 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 staves

CDF


Run2b Silicon

prototype stave

prototype barrel

Well advanced project• the SVX4 chip works!

• the stave concept works!

• prototyping of most components ~finished

• most parts well in time

Laser testped+signal

pedestal subtracted signal

Channel #

A

DC

CDF


Summary

The CDF silicon detector is doing its job and produces good data necessary for the physics program of the experimentA lot of struggling during the commissioningA well organized maintenance plan in place

The innovative Fast displaced tracks trigger is enhancing the experiment capabilities

Still work to be done to fully exploit the Si capabilities (L00 and ISL on the offline analysis)

The TeV program extends over the lifetime of the existing hardware

To fully explore the potential for new physics at CDF the RUN2b silicon is approaching its production phase.

Commissioning, operation and first physics results of the CDF Run2a Silicon and

Documents

Transcript of Commissioning, operation and first physics results of the CDF Run2a Silicon and