Silicon Vertex Tracker (VTX)Silicon Vertex Tracker (VTX)forfor

PHENIX Experiment at RHICPHENIX Experiment at RHIC

Y. Akiba (RIKEN)for

PHENIX collaboration

Detector Advisory Committee Meeting November 22, 2003

VTX proposalVTX proposal

65 authors from 14 institutes 4 institutes outside of present

PHENIX

Main part (VTX barrel)About 100 pages52 figures8 tables

Appendix (EndCap extension)

about 20 pages

16 figures

Pixel barrels (50 m x 425 m)Strip barrels (80 m x 3 cm)Endcap (extension) (50 m x 2 mm)

1 - 2% X0 per layerbarrel resolution < 50 m endcap resolution < 150 m

1.2<||<2.4||<1.2

Silicon Vertex Tracker in PHENIXSilicon Vertex Tracker in PHENIX

Physics Beyond Reach of Current PHENIX Physics Beyond Reach of Current PHENIX

Detailed study of the hot and dense matter formed in Au+Au collision Precise measurement of charm production

Charm enhancement in pre-thermal stageReference for J/ measurement

Beauty measurement in Au+Au collisions Flavor dependence of QCD energy loss in hot matter Thermal di-lepton pair (charm background) High pT charged particle (pT > 10 GeV/c)

G measurement in broad x range in polarized p+p collision Charm/beauty production +jet measurement

Gluon shadowing in broad x range by heavy quark production

Measurements complement and enhance the present physics program• fully exploit existing rare event capabilities of PHENIX

Provide key measurements so far inaccessible at PHENIX:

Open Charm and BeautyOpen Charm and Beauty Physics interest in charm and beauty in Heavy Ion Collisions

Charm enhancement in pre-thermal stage Do heavy quarks lose energy in quark matter? critical base line for J/ and Y production & dilepton continuum

Spin Physics with charm/beauty Gluon polarization in wide

PHENIX measured charm via inclusive electron (PRL88 (2002) 192303) Indirect measurement can not distinguish charm and beauty for pT > 2.5 GeV/c

beauty

charm

Charm and beauty separation aim of future PHENIX program

Physics from precise charm measurementsPhysics from precise charm measurements

Is there pre-thermal charm production?

Precise charm measurementis required to detect small enhancement

Does charm flow? Does charm suffer energy loss?

Charm measurement in pT>3 GeV/c is required to see energy loss effect

Thermal dileptons from the QGP

Di-leptons from charm decaymust be identified and subtracted to detect the thermal di-leptons from the QGP in 1-3 GeV region

These measurements are not possible or very limited without the VTX

D

Detection of decay vertexwill allow a clean identifications of charm and bottom decays

m cGeV m

D0 1865 125 D± 1869 317

B0 5279 464 B± 5279 496

Need secondary vertex resolution < 50 m

Beauty and high pT charm will require high luminosity

Direct Observation of Open Charm and BeautyDirect Observation of Open Charm and Beauty

Detection options:• Beauty and low pT charm through displaced e and/or • Beauty via displaced J/• High pT charm through D K

Au

e

AuD

X

J/

B

X

K

ee

Charm measurements with the VTXCharm measurements with the VTX

Precision DCA (Distance of Closest Approach) measurement by the VTX strongly suppress background from Dalitz and the conversion

More than factor 10 improvements of S/B.

In low pT region, electron spectrum after the DCA cuts is dominated by charm decay

Robust charm measurement at low pT

ce / be separation from the difference of decay length

Extends ce measurement beyonds pT>2.5 GeV/c

Measurement of energy loss of charm

c e by barrel+central arm

Direct measurement of Direct measurement of DDKK

Simulation of DK(pT>2 GeV/c) with VTX

1 % radiation length per layer

After a DCAcuts, 7 significance is achieved for central Au+Au collision

DCA of primary tracks DCA of DK

Signal significance (S/B1/2) of DK

DCA cuts

7

DCA(cm) DCA(cm)

beauty measurement with VTXbeauty measurement with VTX

In high pT (pT>3 GeV/c), the electron spectrum is dominated by beauty decay

Clear separation of b from c using the difference of decay length

b measurement in 1<pT<6 GeV/c, covering >50% of be yield

Accurate beauty measurement is not possible without the VTX

b e by VTX + central arm

Spin Physics with VTXSpin Physics with VTX

Measurement of Gluon polarization by Heavy flavor production c, b e, + displaced vertex B displaced J/ DKat high pt

VTX measurement of displaced vertex Improved S/B higher sensitivity to G(x) Much broader x coverage

VTX significantly increases the x coverage of G(x) measurement

Gamma+JetsGamma+Jets

In p+p or p+A collisions, the VTX works as a stand alone, large solid angle tracker

The VTX is used to detect the recoil jets in the direct photon events.

PYTHIA simulation with the VTX acceptance

RMS resolution of initial parton x is ~20% with the VTX

Without the VTX With the VTX

RMS resolution of x1

Measurement of gluon shadowing with VTXMeasurement of gluon shadowing with VTX

Heavy-flavor measurement in p+A Single lepton and J/ with displaced vertex

Heavy-flavor production via g+g q+q Extracting gluon structure function nuclei, shadowing

vertex detector provides broader range in x into predicted shadowing region (x ~ 10-2 )

coverage w.the VTX

Expected Signal yield in RUN8Expected Signal yield in RUN8

Many of these measurements are not possible or very marginal without the VTX

NO

NO

NO

NO

NO

NO

marginal

limited

limited

limited

limited

limited

Barrel VTX detectorBarrel VTX detector

Summary of the parameters of the VTX

Barrel detector(GEANT model)

Pixel detectorPixel detector

Use pixel detector technology developed for ALICE and NA60

RIKEN/ALICE collaboration Pixel size: 50 x 450 ALICE1LHCb read-out chip

32 x 256 ch / chip Configuration of PHENIX

VTX pixel layer 1 sensor chip (4x128x32

pixels) is read-out by 4 ALICE chips

2 sensor chip / half ladder 2 half ladder / 1 ladder 20 ladders/ pixel layer

1.2 % radiation length R=2.5 cm

Readout Bus

Detector

readout chip

Support/cooling

Half ladder

Pixel detector

Pixel Readout (ALICE PILOT module)Pixel Readout (ALICE PILOT module)

Use a variant of ALICE PILOT module to read-out the pixel data and the data by optical fiber link

10 MHz read-out, 25.6 usec per chip, using the ALICE chip set Some modification may be needed for digital PILOT (R&D)

Analog PILOT(control, etc)

digital PILOT(read pixel data)

Optical link driver chip

(GOL)

Optical package

data

clock & control

Read out BusFrom pixel

Optical I/OPILOT module

Pixel at Work (NA60)Pixel at Work (NA60)

The Pixel detector is used for target spectrometer of NA60 experiment at SPS

A part of RIKEN and StonyBrook group participates in NA60 to gain experience of using the pixel detector in a real experiment

The pixel detector worked very well in the recent In+In run of NA60

The success of NA60 run demonstrates the capabilities of the pixel technology:

High efficiency Low noise hit rate It worked in extremely high

radiation environment (>M rad during the run)

beam test of pixel detector (ALICE)beam test of pixel detector (ALICE)

Beam time; Oct-22 – Nov-08 Indium ion beam on to Sn target RIKEN group participate in the

ALICE beam test 5 single chip + 1 ladder in beam

test Ladder is read by “almost real”

PILOT MCM and “almost real” pixel read-out bus for ALICE

Success to read data with full readout chain Pixel ladder + Pixel Bus + MCM ( Digital Pilot chip + GOL )

Beam test set up for ALICE pixel

Barrel strips detectorBarrel strips detector

Outer 3 layers use Si strip detector technology

Use a novel, single sided, two dimensional read-out sensor developed by Z. Li of BNL Inst. Division

80 x 3 cm strip X/U stereo read-out 384 x 2 x 2 per sensor chip (64.6 mm

x 30.7 mm) V1 prototype was tested by RIKEN

group V2 prototype 400 and 300 thick

is being made. (Will be delivered in this year)

4 sensor chips / ladder R2 (R=6cm) 10 ladders R3 (R=8cm) 14 ladders R3 (R=10cm) 18 ladders

Sensor structure (ver1)

One strip sensor chip

64.6mm

30.7mm

Strips detector read-outStrips detector read-out

Use SVX4 chip developed by FNAL/LBNL for the Tevatron SVTX upgrade

128 ch/chip 50 pitch read-out 42-deep pipe line On-board 0-suppression

Designed for AC coupled device. (Z.Li sensors DC-coupled)

Frequent storage-cap reset AC/DC conversion by RC

chip in the pitch adaptor

Recently, Tevatron SVTX upgrade project was cancelled. Three are already sufficient SVX4s produced. We are in negotiation with FNAL to purchase these chips.

SVX4 chip

One

sen

sor

Sensor bond-pad rows

ASICX-View

A-C

ASICX-View

D-F

ASICU-View

A-C

ASICU-View

D-F

One

RO

CSVX4

U-View(A)

SVX4U-View

(B)

SVX4U-View

(C)

SVX4U-View

(D)

SVX4U-View

(E)

SVX4U-View

(F)

SVX4X-View

(A)

SVX4X-View

(B)

SVX4X-View

(C)

SVX4X-View

(D)

SVX4X-View

(E)

SVX4X-View

(F)

X-V

iew

Rea

dout

U-V

iew

Rea

dout

One

sen

sor

Sensor bond-pad rows

ASICX-View

A-C

ASICX-View

D-F

ASICU-View

A-C

ASICU-View

D-F

One

RO

CSVX4

U-View(A)

SVX4U-View

(B)

SVX4U-View

(C)

SVX4U-View

(D)

SVX4U-View

(E)

SVX4U-View

(F)

SVX4X-View

(A)

SVX4X-View

(B)

SVX4X-View

(C)

SVX4X-View

(D)

SVX4X-View

(E)

SVX4X-View

(F)

X-V

iew

Rea

dout

U-V

iew

Rea

dout

Cooling / Support Structure

SVX4sROCsSensorCooling / Support Structure

SVX4sROCsSensorCooling / Support Structure

SVX4sROCsSensorCooling / Support Structure

SVX4sROCsSensor

SVX4sROCsSensor

a)

b) c)O

ne s

enso

r

Sensor bond-pad rows

ASICX-View

A-C

ASICX-View

D-F

ASICU-View

A-C

ASICU-View

D-F

One

RO

CSVX4

U-View(A)

SVX4U-View

(B)

SVX4U-View

(C)

SVX4U-View

(D)

SVX4U-View

(E)

SVX4U-View

(F)

SVX4X-View

(A)

SVX4X-View

(B)

SVX4X-View

(C)

SVX4X-View

(D)

SVX4X-View

(E)

SVX4X-View

(F)

X-V

iew

Rea

dout

U-V

iew

Rea

dout

One

sen

sor

Sensor bond-pad rows

ASICX-View

A-C

ASICX-View

D-F

ASICU-View

A-C

ASICU-View

D-F

One

RO

CSVX4

U-View(A)

SVX4U-View

(B)

SVX4U-View

(C)

SVX4U-View

(D)

SVX4U-View

(E)

SVX4U-View

(F)

SVX4X-View

(A)

SVX4X-View

(B)

SVX4X-View

(C)

SVX4X-View

(D)

SVX4X-View

(E)

SVX4X-View

(F)

X-V

iew

Rea

dout

U-V

iew

Rea

dout

Cooling / Support Structure

SVX4sROCsSensorCooling / Support Structure

SVX4sROCsSensorCooling / Support Structure

SVX4sROCsSensorCooling / Support Structure

SVX4sROCsSensor

SVX4sROCsSensor

a)

b) c)

Read-out scheme:2 Read-Out Cards (ROCs) mounted on each sensor. Each ROC has 6 SVX4s

Silicon Vertex Tracker R&DSilicon Vertex Tracker R&D

Beam test at KEK by RIKEN/Kyoto

=52 =35 =45 =35 =49

Source test at RIKEN

MechanicMechanical structureal structure and cooling and cooling

• Different structures were considered Choose single-barrel shape. • Material: GFRP• Cooling• Radiation length: <1% per layer

Design of support structure by HYTEC Cooling of the barrel

FEM analysis

Gravity deformation

Distortion from thermal strains

Remaining R&DRemaining R&D

Pixel Detector Pixel readout bus

Design and prototyping by Sep 2004 PILOT module

Modification of digital pilot chip to meet PHENIX specification

Technology choice (modified ASIC or FPGA) by April 2004 Pixel FEM

First prototype by Sep 2004 Strip detector

Full chain test of SVX4 read-out of the strip sensorUse the second proto-type of the strip sensorTest completed by April 2004

the SVX4 read-out cardThe first prototype cycle completed by July 2004

Integration Specifications of mechanical design Mechanical design study

R&D support from RIKEN and DOE. Request DOE R&D fund of ~$280K

BudgetBudget

Contribution from RIKEN $3M for 2004-2006+ man-power, etc (~ $1M)

Total DOE costs:$5.6M in FY05-07Direct: $3.7MOverhead: $0.3MContingency $1.6M (~40%)

Profile for the DOE costs

Q1 Q2 Q3 Q4 FY2005

Q1 Q2 Q3 Q4 FY2006

Q1 Q2 Q3 Q4 FY2007

$0.5M/Q

scheduleschedule

Start construction in FY05 Construct in FY05-07 Part of the VTX will be built and installed for RUN7 Complete detector installed in RUN8

2003 2004 2005 2006 2007

SummarySummary Physics with the VTX detector

Au+AuPrecise measurement of charm productionEnergy loss of charm at high ptBeauty production

Polarized p+pG(x) measurement in wide x range (polarized proton)

p+A (d+A)Gluon shadowing in wide x range

Proposed Silicon vertex detector 1 pixel layer 3 strips layers R&D in past 2 years

Cost and Schedule Ready for start of construction in FY05 $3M contribution from RIKEN $5.6M of total cost for the DOE in FY05-07 Install the full detector in RUN8 (FY08)

backupsbackups

Silicon strip detector R&DSilicon strip detector R&D

Prototype v.2 p+ line: 7m 5m gap: 6m 3m turn: 3 turns 5 turns delivery: December

Test readout board SVX4 readout chip by

FNAL/Berkeley collaboration I/F board to PHENIX DAQ by

ORNL PHENIX DAQ emulation on

PC

CDF hybrid

SV

X4

SV

X4

SV

X4

SV

X4

CDF hybrid I/F board

FPGA

I/O FIFO

cable

USB

PCLabViewGUI

v.2 prototype sensor

pitch adapter

Silicon strip detector R&DSilicon strip detector R&D

Laser test bench at BNL instrumentation to study basic properties of the sensor to find optimum operation parameters