Solid State Detectors for Upgraded PHENIX Detector at RHIC

1991 – Project Inception 1997 – First ion collisions in RHIC 2002 – statements of major discovery Bits of history SMD/ FCAL Maturity and planning for the next 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 p T –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 layers r=5.0 cm, Δz~±10 cm r=2.5 cm, Δz~±10 cm Strip layers r=10.0 cm, Δz~±16 cm r=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 chip Support/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 data clock & control Read out Bus From 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 cm 2 625/500 μ m 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 u3x3 u1 x1 x2 CV IV

End Caps: Wedge shaped strip detectors

W-Si Forward Calorimeters

Calorimeters: numerology  0 identifier (shower max detector) Sensors168 6x6 cm 2, 600 , single sided, single layer, 2-d readout (stripixels) Pitch0.5 mm Readout channels43000 SVX4336 Electromagnetic (fine) section Sampling structure5mm x mm W mm Si + PCB + protection and air gap Sensors2688 6x6 cm 2, 300  Si, 15x15 mm 2 readout pads, 168 sensors per layer Readout channels53766 or 10 pads are ganged per readout channel Hadronic (coarse) section Sampling structure18 mm x mm W mm Si + PCB + protection and air gap Sensors per layer Readout channels31366 pads are ganged per readout channel

Calorimeters: Sampling cell design Detector ladder glued to the W plate To avoid draining bulk current into electronics; loss of electronics whenever channel trips; and to save space Thin film technology used to implement rc-chip on interconnect board Absorber (W) Sensors carrier board

AC Coupled Si Detector SiO 2 p+ n+n+ Al SiO 2 +Si 3 N 4 Polysilicon bias resistors bias strip Calorimeters: solution to decoupling 30% extra cost $160 -> $240 for 6x6 cm 2 detector

Prototype Silicon Wafers For Calorimeter 62 mm Si Wafer : 4x4 pads of detection (15x15 mm 2 ) 4” High resistive wafer : 5 K  cm Thickness : 300 microns  3 % Tile side : mm mm Guard ring In Silicone ~80 e-h pairs / micron  e - /MiP Capacitance : ~80 pF Leakage current : 5 – 15 nA Full depletion bias : ~100 V Nominal operating bias : 150 V ELMA: Well established technology; Long production history Good reputation

Calorimeters:  0 identifier RC SVX4 Test structure mask X Y 500 

Upgrade Schedule Scenario Aerogel TOF-W HBD VTX-barrel VTX-endcap NCC MuTrigger DAQ R&D PhaseConstruction 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

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 module With SVX4 readout chip