IBL Overview Darren Leung ~ 8/15/2013 ~ UW B305

ATLAS Pixel Upgrade Phase 0 (2013): Phase 2 (2022): IBL will extend the pixel detector to a 4 layer system L ~ 6x1033 cm-2s-1 Phase 2 (2022): New ATLAS tracker for pixels and strip detectors L ~ 5x1034 cm-2s-1

Why? Motivations: Tracking robustness Increased luminosity Tracking precision Beam pipe replacement Large radiation doses

What we need (1) Higher radiation hardness Improve radiation hardness by factor of 5 5x1015 neqcm-2 NIEL (nonionizing energy loss) Max dissipation of 200 mW/cm2 at -15 degrees C Tracking efficiency > 97%

What we need (2) New readout chip Finer segmentation, more active area, improved hit rate Smaller cell size (50 by 250 µm) Higher radiation hardness–250 Mrad TID Rad = 0.01 J/kg of absorbed radiation TID = total ionizing dose

What we need (3) Lighter detector Lower radiation length in support and cooling Improvement in radiation length per layer from 2.7% to ~1.5% Less weight and less cost More efficient cooling New off detector readout system, matched to fe14, twice as fast

Specifications IBL Properties Smaller inner radius (26.5 mm) B-layer radius = 50.5 mm Supported by 14 staves 32 FE-14 chips per stave =448 chips total Four 3D sensors Twelve planar sensors

Modules Operation tracking efficiency of >97% Max total non-ionizing fluence of 5x1015 Neq/cm2 Max operational voltage <1000 V Max power dissipation of 200 mW/cm^2 New “slim edge” design for planar sensors

“Slim-edge” design Edge pixels on electrode side overlap guard ring area 13 guard rings manage the potential drop between bias contact and edge of sensor Minimizes inactive edge  increase in active area

Modules Planar 3D sensors N in n sensor 16.8x40.9 (mm) Contains two FE-14 chip Requires lower temperature N in p sensor 16.9x20.0 (mm) Contains one FE-14 chip More complex to manufacture

FE-14 Lower noise and threshold Higher data rates IBM 130 nm CMOS process Smaller pixels (50x250 um) from (50x400 um) 80x336 = 26880 pixels

Staves IBL modules supported by 14 local supports Cylindrically arranged Based on carbon foam material for heat transfer to cooling pipe Electrical supplies and read outs

Carbon Foam Transmits module heat from faceplate to cooling pipe. Density of 0.22 g/cm^3 and thermal conductivity of ~30 W/mK as compromise. Matched thermal expansion with module Low mass and high thermal conductivity

Cooling Titanium cooling pipe (1.5 mm) CO2 cooling system working at -40 degrees C (chosen over current C3F8)

Staves (3) Carbon fiber Omega glued to foam to provide rigidity 3 layer faceplate (0/90/0 fiber orientation)

Radiation Length Function of pseudorapidity (-3 < Eta < 3) Goal =1.5% Affected by -Material budget -Engineering limits

Other Layers Omega Laminate Carbon Foam

Integration Gluing modules to staves Quality assurance tests on-site Brazing of cooling pipe extensions to stave Mounting of staves around the beam pipe Connection of power and readout (routing along the beam pipe Final surface test of IBL before installation

Conclusion—Were our goals met? New pixel detector for first upgrade of tracking system New generation pixel chip New support and cooling system Construction and installation expected to be completed in 2013 LHC shutdown

Citations “ATLAS Insertable B-Layer Technical Design Report” CERN Document Server. N.p., n.d. Web. 15 Aug. 2013. “The ATLAS Insertable B-Layer Pixel Detector” Proceedings of Science. N.p., n.d. Web. 15 Aug. 2013.