Solid State Detectors for Upgraded PHENIX Detector at RHIC

1991 – Project Inception1997 – First ion collisions in RHIC2002 – statements of major discovery

Bits of history

SMD/

FCALFCAL

2003 - Maturity and planning for the next

10-15 years

Precision measurements,

extended coverage

PHENIX Upgrade

Solid State Upgrade components

• Central Barrel Silicon Tracker – Two layers of pixels (ALICE);– Two layers of StriPixels;

• Forward Silicon Trackers (South and North)• Four layers of silicon discs (short strips with pixel-type

readout) each;

• Forward W-Si Calorimeters (South and North)• 22 layers of 6x6 cm2 pad sensors (15x15 mm2 pads);• One layer of StriPixel Detectors (0.5 x 60 mm2 strips)

• Specifications– 4 layers with large acceptance ( & < 1.2)– Displaced vertex measurement : < 40 m– Charged particle tracking : p/p ~ 5% p at high pT

– Working detector for both of heavy ion and pp collisions

• Technology Choice– Hybrid pixel detectors in 2 inner layers– Stripixel sensors w/ SVX4 readout chip in 2 outer

layers

Barrel VTX Detector

Pixel layersr=5.0 cm, Δz~±10 cmr=2.5 cm, Δz~±10 cm

Strip layersr=10.0 cm, Δz~±16 cmr=14.0 cm, Δz~±19 cm

Beam pipe

Barrel: Pixel Detectors

• Technology choice: – ALICE1LHCb read-out chip

32 x 256 ch / chip– 4 chips bump bonded to sensor

with pixel size: 50 x 450 – Grouped to ladders– Readout through pilot module

• R&D with ALICE and NA60– Adapt technology to PHENIX – Detectors operated in NA60

Readout Bus

Sensor

Readout chipSupport/cooling

Half ladder

Pixel detector

NA60 In-In collision taken 2003

Analog PILOT(control, etc)

digital PILOT(read pixel data)

Optical link driver chip

(GOL)

Optical package

dataclock & control

Read out BusFrom pixel Optical I/O

PILOT module

Barrel: Strip Detector• Strip sensor

– BNL’s new “stripixel” concept : single-sided sensor w/ 2-D position sensitivity

– Charge sharing by 2 spirals in one pixel (80 μm ×1000 μm)& projective x/u-strip readout

– Pre-production sensor (Hamamatsu)

• p+/n/n+ structure• 3.5×6.4 cm2

• 625/500 μm thickness• Spiral : 5/3μm line/gap• Pixels :

384×30×2=23,040• Strips : 384×2×2=1,536

– Probing tests are on-going for evaluation

Z. Li, NIMA518, 738 (2004)

x3’ u1’ u2’

x2’ x1’ u1’u2 u3 x3

u1 x1 x2

0.00E+00

1.00E-12

2.00E-12

3.00E-12

4.00E-12

5.00E-12

6.00E-12

7.00E-12

8.00E-12

9.00E-12

1.00E-11

0 50 100 150 200 250 300 350 400

V_bias [V]

C [

F]

0.00E+00

5.00E-10

1.00E-09

1.50E-09

2.00E-09

2.50E-09

3.00E-09

3.50E-09

0 50 100 150 200 250 300 350 400

V_bias [V]

I [A

]CVIV

End Caps: Wedge shaped strip detectors

Backplane

-V

R Amplifier

GND

C

W-Si Forward Calorimeters

Calorimeters: numerology

0 identifier (shower max detector)

Sensors 168 6x6 cm2, 600, single sided, single layer, 2-d readout (stripixels)

Pitch 0.5 mm

Readout channels 43000

SVX4 336

Electromagnetic (fine) section

Sampling structure 5mm x 16 2.5 mm W + 0.3 mm Si + PCB + protection and air gap

Sensors 2688 6x6 cm2, 300 Si, 15x15 mm2 readout pads, 168 sensors per layer

Readout channels 5376 6 or 10 pads are ganged per readout channel

Hadronic (coarse) section

Sampling structure 18 mm x 6 15.5 mm W + 0.3 mm Si + PCB + protection and air gap

Sensors 1176 196 per layer

Readout channels 3136 6 pads are ganged per readout channel

Calorimeters: Sampling cell design

Backplane

-V

R Amplifier

GND

C

Detector ladder glued to the W plate

To avoid To avoid draining bulk current into electronics;draining bulk current into electronics;loss of electronics whenever channel trips;loss of electronics whenever channel trips;

and to save spaceand to save space

Thin film technology used to implement rc-chip on interconnect board

Absorber (W)

Sensors carrier board

AC Coupled Si Detector

SiO2

p+n+

Al

AlSiO2+Si3

N4

Polysilicon bias resistors

bias strip

Calorimeters: solution to decoupling

30% extra cost

$160 -> $240 for 6x6 cm2 detector

Prototype Silicon Wafers For Calorimeter

62 mm

62 m

m

Si Wafer :4x4 pads of detection

(15x15 mm2)

4” High resistive wafer : 4” High resistive wafer : 5 K5 Kcmcm

Thickness : 300 microns Thickness : 300 microns 3 % 3 %

Tile side : Tile side : 62.0 + 0.062.0 + 0.0

- 0.1 mm- 0.1 mm

Guard ringGuard ring

In Silicone ~80 e-h pairs / micron In Silicone ~80 e-h pairs / micron 24000 e24000 e-- /MiP/MiP

Capacitance : ~80 pFCapacitance : ~80 pF

Leakage current : 5 – 15 nALeakage current : 5 – 15 nA

Full depletion bias : ~100 VFull depletion bias : ~100 V

Nominal operating bias : 150 VNominal operating bias : 150 V

ELMA:Well established technology;Long production historyGood reputation

Calorimeters: 0 identifier

RC

RCSVX4

SVX4

Test structure mask

X

Y500

Upgrade Schedule Scenario

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Aerogel

TOF-W

HBD

VTX-barrel

VTX-endcap

NCC

MuTrigger

DAQ

R&D Phase Construction Phase Ready for Data

BACKUPS

Stripixel Sensor : Principle• A novel “stripixel” detector concept innovated by BNL

Instr. Div. : Z. Li, NIMA518, 738 (2004).– Single-sided sensor

– 2-dimentional position sensitivity by charge sharing

– Two independent electrodes interleaved in one pixel are projectively read out by strips.

• Advantages (compared with a double-sided strip sensor)– Simple structure : reduce costs and integration issues

– Radiation hard (cf. a complicated n+ side structure in a double-sided strip sensor)

• Disadvantages– Large capacitance/strip due to the interleaving scheme

– Decrease in S/N due to charge sharing

1000 m

80 m

U-pixel(1stmetal)

X-pixel(1stmetal)

2nd MetalX-strip

2nd MetalU-strip

FWHMfor chargediffusion

BondingPad forX-strip

Go toBondingPad forU-strip

Z. Li, Inst. Div., BNL

Silicon Strips Detectors for Central Tracker

• Sensor technology choice:– 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)

• Readout chip technology choice:– SVX4 chip developed by FNAL/LBNL – 128 ch/chip– 50 pitch read-out

• Ongoing R&D– Sensor prototype tests – Tests of SVX4 readout with sensor

Sensor structure

SVX4 chip

Design of the test hybrid moduleWith SVX4 readout chip