1. IBL Overview
Darren Leung ~ /15/ ~ UW B305

2. 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

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

4. 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%

5. 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

6. 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

7. 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

8. 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

9. “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

10. 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

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

12. 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

13. 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

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

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

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

17. Other Layers
Omega Laminate
Carbon Foam

18. 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

19. 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 LHC shutdown

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