Overview of the ATLAS Insertable B-Layer (IBL) Project Sebastian Grinstein (IFAE-Barcelona) For the ATLAS Collaboration “8 th International Hiroshima Symposium on the Development and Application of Semiconductor Tracking Detectors” Academia Sinica, Nankang, Taipei -- 5 th -8 th December, 2011.
ATLAS Overview • Central trackers in a solenoidal magnet • EM + hadronic calorimeters • Muon spectrometer in toroidal magnets ATLAS Inner Detector S. Grinstein (IFAE) - HSTD 2011 Straw tubes Silicon strip Silicon pixel 2 IBL
ATLAS Pixel Detector • Why pixels? Position resolution Ø Critical for physics program (Higgs, SUSY searches, top,...) • ATLAS Pixel Detector Ø 3 barrels + 6 disks inner layer radius: 50.5mm Ø 1744 modules, 80M channels Ø ~1.8 m 2 active area, | η |<2.5 • ATLAS Pixel Module Ø 16 FE chips (FE-I3) + Controller Chip Ø 2880 channels/chip; 50 µm x 400 µm (50 µm x 600 µm between FEs) Ø Planar n-on-n DOFZ silicon, 256 µm thick Ø Designed for 1E15 1MeV neq/cm2 fluence 3 S. Grinstein (IFAE) - HSTD 2011
Insertable B-Layer (IBL) • New (4 th ) pixel layer mounted directly on beam-pipe § radius=33mm, | η |<2.5, 0.2m 2 § ¡ requires new (smaller) beam-pipe ¡ • Reasons for IBL: § Back-up existing B-Layer (hard failures) § Improve physics performance (Based on smaller radius and low mass) Current pixel Stringent requirements on sensor and front-end electronics • Need of larger and faster font-end chip • Better radiation hardness that current IBL detector S. Grinstein (IFAE) - HSTD 2011 To be installed in 2013/14 4
Insertable B-Layer (IBL) • Layout : § 14 Staves, each with 32 front-end chips § No overlap on Z due to space restriction § Operate at -15 C, CO 2 cooling, Ti pipe • Front-end/Sensor Design: § NIEL dose = 5x10 15 n eq cm -2 (w/ safety factor) § Ionizing dose ≥ 250 Mrad § Small dead area (slim/active edge) § Max sensor power < 200 mW/cm 2 @ -15 C § Max bias voltage: 1000V • Sensor Technology: § Planar n-on-n and 3D double sided being considered Sensor facing beam § 75% Planar and 25% 3D sensor layout: 3D Planar 3D S. Grinstein (IFAE) - HSTD 2011 5
IBL: Font End Chip: FE-I4 (“A”) • Biggest chip in HEP to date Medipix • Higher active fraction (x6) (than ATLAS predecessor) • Local memory cells (bus activity only on readout) → Lower power • Higher data rate FE-I3 • More radiation hard (130nm FE-I4 technology) FDAC TDAC size (um2) 50x250 4 Bit 5 Bit V fb local Pixel array 80x336 V th local + V fb2 + feedback threshold tune tune Chip size (mm2) 20.2x19.0 feedbox feedbox Active fraction (%) 89 C f1 C f2 C inj1 NotKill Analog/Digital current (uA/pix) 10/10 Inj0 HitOut + C c injectIn - Preamp Amp2 Analog/Digital voltage (V) 1.5/1.2 Inj1 C inj2 LVDS output (Mb/s) 160 • Pixel above threshold • Time over threshold Pixel sixe (um2) 50 x 250 (~collected charge) ToT Resolution 4-bit ToT 6 S. Grinstein (IFAE) - HSTD 2011
Planar Pixel Sensors for the IBL • Proven technology current ATLAS detector: n-on-n pixels (DOFZ silicon) • Bias grid to evaluate sensor quality before bump-bonding • Thinner substrate (200um, was 250um) Vendor: • Slim edge design (~200um, was 1mm) CiS-Germany • Guard rings on p-side shifted beneath outer pixels (longer outer pixels to keep sensor length design) • Distorts electric field on the sensor edge, but charge collection after irradiation dominated by region directly beneath implant D. Muenstermann Two FE-I4 chip IBL planar sensor tile 500um long ~200um 250um 7 7 pixel inactive edge S. Grinstein (IFAE) - HSTD 2011
3D Pixel Sensors • Pixel electrodes penetrate into the substrate: depletion region grows parallel to wafer surface • Double sided process, p-bulk 230um thick, (FZ high resistivity wafers) • Two vendors producing IBL 3D sensors with same specifications: CNM (Spain) and FBK (Italy) CNM 3D IBL sensors: 200um G. Pellegrini • 210um columns • 3D Guard ring + fences (200um) • Evaluate sensor quality on GR Probe pad for quality assurance 3D Guard ring p+ implant (fences) 8 S. Grinstein (IFAE) - HSTD 2011
3D Pixel Sensors FBK 3D IBL sensors: • Pass-through columns • 200um inactive edge fences • Evaluate sensor quality with temporary metal on each row of pixels (strip) G-F. Dalla Betta Cut-line Temporary Ohmic 200um slim edge metal columns probing pads Junction columns 9 S. Grinstein (IFAE) - HSTD 2011
IBL Sensor Selection Planar and 3D sensors have to meet wafer quality (bow, thickness tolerance, etc) and electrical specifications (leakage current, Vbreak) FBK Sensor IV for 80 strips Planar : V break > 60V 10nA S. Grinstein (IFAE) - HSTD 2011 50V CNM Sensors CNM: leakage current along the GR region 10
Bump-Bonding • To reduce the amount of inactive material, FE-I4 are thinned to 90um • Through the bump-bonding process the bowing of the thinned chip can cause unconnected pixels • Production of dummy sensors and chips to carry out bump-bonding studies FE-I4 Sensor CNM FEI4-8, 12 bad chains 2 pixels shorted FE-I4 Chip Test pads 10 pixels shorted Chip Substrate 11 Problematic areas identified at Barcelona S. Grinstein (IFAE) - HSTD 2011 11
Bump-Bonding • At IZM (Germany) the thinned chip (90um) is attached to a glass support during the heating step of the bonding cycle • Glass support laser-removed after cycle completed • Successfully used in IBL pre-production modules S. Grinstein (IFAE) - HSTD 2011 12
FBK 3D Device IBL Module Planar Module • First single chip modules mounted • Temporary pigtail will be cut and replaced by flex wing S. Grinstein (IFAE) - HSTD 2011 13
Irradiated IBL Devices Several planar and 3D IBL devices irradiated to IBL fluencies (5E15 neq/cm2) • Planar devices irradiated to Planar device IBL fluencies comply with Before annealing the power dissipation limits at 1000V bias 3D FBK Device p-irr 5E15 neq/cm2 • For 3D devices (here FBK) irradiated to IBL fluencies power dissipation is not a constraint 14 S. Grinstein (IFAE) - HSTD 2011
Device Performance • Irradiated and non-irradiated devices characterized before test-beams • Study of lowest operational threshold of devices Planar 4E15 n-irr Planar Threshold distribution S. Grinstein (IFAE) - HSTD 2011 Difficult to go to lower threshold Low threshold operation possible for irradiated devices: FBK 5E15 p-irr 1500e threshold used at test-beams FBK 5E15p-irr Noise ~140e 15 Ø Operation at ~1500e threshold possible
Device Performance 3D p-irradiated devices (5E15neq/cm2) Noise increase with bias voltage: Ø So does charge collection: which is the optimal bias voltage 16 for 3D devices? S. Grinstein (IFAE) - HSTD 2011
Device Performance S. Grinstein (IFAE) - HSTD 2011 Optimal voltage for CNM 5E15neq/cm2 irradiated devices ~ 160V • Optimal high voltage for 3D CNM devices ~160V (~150V for FBK) • For planar devices limited by electrical constraints to 1000V 17
Test-beam Results 3D design 3D (CNM) • Pixel efficiency map CNM81 • Low threshold operation (1500e) ε =97.5% y r n-irr 5E15 a n • Noisy, dead pixels masked out i m 160V, 0 deg i l e • Efficiency determined from r P FBK13 extrapolated track on devices ε =98.8% Unirradiated • Efficiencies comply with IBL 20V, 0 deg requirements Planar n-irr 4E15 neq/cm2 ~215 um 500 um long edge pixel Bias = 1000V, phi = 15° Overall efficiency = 99.0 % 18 Ø More results: Igor Rubinsky’s talk S. Grinstein (IFAE) - HSTD 2011
Summary • ATLAS plans to insert a 4 th layer (IBL) in 2013/14 • Planar and 3D pixel technologies being evaluated for IBL – 75% planar + 25% 3D layout being investigated • Planar and 3D devices within the IBL requirements have been produced – Both technologies well developed – Inactive edges of ~ 200 um – High efficiency (>97%) after irradiation (5E15 n eq /cm 2 ) has been achieved (see also Igor R. talk) • Final planar and 3D sensor productions underway S. Grinstein (IFAE) - HSTD 2011 19
Back-up Slides S. Grinstein (IFAE) - HSTD 2011 20
Irradiation of IBL Devices • Several planar and 3D IBL devices irradiated to IBL fluencies (5E15 neq/cm2): • Proton irradiation at KIT (beam energy 23 MeV) ü Estimated TID dose ~ 750Mrad (IBL requirement: 250Mrad) • Neutron irradiation at Ljubljana • Devices annealed: 120min at 60C for test-beam 3D devices 21 S. Grinstein (IFAE) - HSTD 2011
LHC and ATLAS Upgrade Plans Integrated Luminosity → 5x10 34 cm -2 s -1 1x10 34 → 7 TeV 14 TeV ~2x10 34 cm -2 s -1 3000 fb -1 LS 2 → 1x10 34 cm -2 s -1 10 27 → ~300 fb -1 2x10 33 cm -2 s -1 LS 2 New ID IBL ~50 fb -1 LS 1 (ATLAS pixel-related upgrades) ~10 fb -1 2013/14 ~2017 ~2022 Year Now [Based on T. Kawamoto, TIPP2011] Ø LHC has plans upgrades (increasing luminosity) to ultimately collect ~3000/fb Ø ATLAS needs to maintain excellent position resolution (vertexing, tracking) 22 S. Grinstein (IFAE) - HSTD 2011
Recommend
More recommend
