1. Module Radiation Length

2. Goals Estimate the expected radiation length of a module, based on the design and measurements on as-built modules Determine causes of differences from original Nov08 estimate Estimate how things change with 130 nm ASICs – Target the important mass issues 2Module Radiation Length

3. Original Prediction 2008 Prediction Copper (L1 to 4)0.122% Copper (Shield)0.000% ASICs0.075% Solder0.000% Kapton0.012% Discretes0.068% Silver Epoxy0.007% Flash metal0.011% Solder Resist0.005% Sensor0.338% Epolite Glue0.005% 2 Bare Hybrids0.150% 2 Stuffed Hybrids0.300% Module0.644% Module Radiation Length3 Common X0 for materials based on SCT barrel module spreadsheet Area of hybrid – Original estimate: 20 mm x 100 mm Polyimide thicknesses of (50, 25, 25) mm (est.) Copper layers – Thicknesses of (25, 12, 12, 25) mm with (.6,.4,.6,.6) coverage SMD from last module

4. Radiation Lengths Under Question Material Previous X0 (mm) Previous Assumed Make-up New X0 (mm) Current assumed Make-up Polyimide357.5Epoxy286Polyimide Poly+adhsv357.5Epoxy286Polyimide Ceramic Caps54.3BaTiO 3 ( should be 19.1)18.486% BaTiO 3, 8% Ni, 6% Sn SMD resistors63.3Al 2 O 3 3986% Al 2 O 3, 8% Ni, 6% Sn Silver Epoxy8510% Ag, 90% Epoxy3570% Ag, 30% Epoxy SolderN/A 8.9262% Sn, 2% Ag, 36% Pb Wire BondsN/A 8999% Al, 1% Si Past estimate for ceramic capacitors grossly understates importance for module’s radiation length. SMD resistors and silver epoxy are also underestimated but not a large fraction of module. Solder is a significant source of material not included in past estimates, will use for current as-built and future estimates. From weight measurement 0.18 g per hybrid using re-flow SMD attach. Addition of wire bonds and change to polyimide are not significant addition of material.. 4Module Radiation Length

5. Polyimide Radiation Length http://rnc.lbl.gov/hft/hardware/docs/pixel_ra d_length.pdf http://rnc.lbl.gov/hft/hardware/docs/pixel_ra d_length.pdf – RL = 28.6 cm https://confluence- new.slac.stanford.edu/download/attachments /12222/MMS_Density_Final_Update.pdf https://confluence- new.slac.stanford.edu/download/attachments /12222/MMS_Density_Final_Update.pdf – RL = 28.2 cm http://pdg.lbl.gov/2002/atomicrpp.pdf – RL = 28.6 cm 5Module Radiation Length

6. Silver Epoxy Radiation Length http://personalpages.to.infn.it/~tosello/EngMeet/ITSm at/SDD/Epotek-E4110.html http://personalpages.to.infn.it/~tosello/EngMeet/ITSm at/SDD/Epotek-E4110.html – RL= 4.9cm http://lhcb.physik.uzh.ch/ST/software/det/index.php – See “Excel spreadsheet” RL= 3.5cm http://cdsweb.cern.ch/record/1279627/files/PH-EP- Tech-Note-2010-013.pdf http://cdsweb.cern.ch/record/1279627/files/PH-EP- Tech-Note-2010-013.pdf – Use epoxy (30%) + silver (70%) and use formalism to calculate RL = 3.4cm 6Module Radiation Length

7. SMD Capacitors Radiation Length Capacitors used (X7R) have a BaTi03 ceramic –RL=1.9 cm (RAL RL calculator) –RL=1.9 cm http://personalpages.to.infn.it/~tosello/EngMeet/ITSmat/ SDD/SDD_BaTiO3.html http://personalpages.to.infn.it/~tosello/EngMeet/ITSmat/ SDD/SDD_BaTiO3.html –Density of 5.85 match measurements of components With estimated solder-end materials (8% Ni, 2% Sn, 2% Cu) – http://personalpages.to.infn.it/~tosello/EngMeet/ITSmat/ SDD/X7R_0805.html http://personalpages.to.infn.it/~tosello/EngMeet/ITSmat/ SDD/X7R_0805.html – RL = 1.84 cm For SMD resistors AlO3 with estimated solder-end materials (8% Ni, 6% Sn) – RL=3.9 cm 7Module Radiation Length

8. With updated radiation lengths NIKHEF08 Prediction NIKHEF08 (Correct X0) Copper (L1 to 4)0.122% Copper (Shield)0.000% ASICs0.075% Solder0.000% Kapton0.012% 0.015% Discretes0.068% 0.162% Silver Epoxy0.007% 0.017% Flash metal0.011% Solder Resist0.005% 0.006% Sensor0.338% Epolite Glue0.005% 2 Bare Hybrids0.150% 0.153% 2 Stuffed Hybrids0.300% 0.407% Module0.644% 0.751% Module Radiation Length8 Biggest difference is the discretes increasing by ~0.1% per module Increase of 17% from original prediction

9. Current area of hybrid and ASICs Area of hybrid – Original estimate: 20 mm x 100 mm – Actual build: 24 mm x 108 mm (+30% area increase) Area of ASICs – Original estimate: 7.5 mm x 7.5 mm – Actual build: 7.55 mm x 7.8 mm (+5% area increase) Module Radiation Length9 NIKHEF08 Prediction NIKHEF08 (Correct X0+ areas) Copper (L1 to 4)0.122% 0.158% Copper (Shield)0.000% ASICs0.075% 0.079% Solder0.000% Kapton0.012% 0.019% Discretes0.068% 0.162% Silver Epoxy0.007% 0.018% Flash metal0.011% 0.014% Solder Resist0.005% 0.008% Sensor0.338% Epolite Glue0.005% 0.007% 2 Bare Hybrids0.150% 0.199% 2 Stuffed Hybrids0.300% 0.457% Module0.644% 0.802% Increase of 24% from original prediction

10. Difference to Actual Build 5 th copper layer – Added 20  m thick Cu layer with 94% coverage and 50  m of modified polyimide adhesive Solder – Not included in original estimate – Measure 0.17 gram per hybrids with X0 =8.9 mm (as-built) Polyimide – X0 of 357 mm with thicknesses of (50, 25, 25)  m (est.) – X0 of 286 mm with thicknesses of (50, 50, 50, 50)  m (as- built) Copper layers – Thicknesses of (25, 12, 12, 25) mm with (.6,.4,.6,.6) coverage (est.) – Thicknesses of (15, 15, 15, 15)  m with (.69,.16,.88,.94) coverage (as-built) SMDs set to match as-built Module Radiation Length10 NIKHEF08 (Correct X0+ areas) Actual Build (with shield) Copper (L1 to 4) 0.158%0.149% Copper (L5- shield) 0.000%0.071% ASICs 0.079% Solder 0.000%0.048% Kapton 0.019%0.038% Discretes 0.162%0.059% Silver Epoxy 0.018% Flash metal 0.014% Solder Resist 0.008%0.007% Wire Bonds 0.000%0.002% Sensor 0.338% Epolite Glue 0.007%0.012% 2 Bare Hybrids 0.199%0.279% 2 Stuffed Hybrids 0.457%0.483% Module 0.802%0.834% Increase of 4%

11. As-built Module W/O Shield 2010 Actual Build 2010 w/o shield Copper (L1 to 4)0.149% Copper (Shield)0.071%0.000% ASICs0.079% Solder0.048% Kapton0.038%0.028% Discretes0.059% Silver Epoxy0.018% Flash metal0.014% Solder Resist0.007% Sensor0.338% Epolite Glue0.012% 2 Bare Hybrids0.279%0.198% 2 Stuffed Hybrids0.483%0.401% Module0.834%0.754% Module Radiation Length11 Decrease of 10% Removing Shield layer – Removes 20  m thick Cu layer with 94% coverage and 50  m of modified polyimide adhesive

12. Improvements with 130 nm Reduce area of hybrid – Actual build: 24 mm x 108 mm – For 130 nm: 12 mm x 96 mm Copper layers – 130 nm assume shieldless with traces embedded into power layer (removes 50  m polyimide) As-built coverage:.69,.16,.88,.94 Estimate:.69,.88,.91 Chips, Epolite, SMD, solder and silver epoxy reduced by ~half Module Radiation Length12

13. Module Radiation Length Summary 2010 w/o shield 130 nm Estimate Copper (L1 to 4)0.149%0.062% ASICs0.079%0.039% Solder0.048%0.028% Kapton0.028%0.008% Discretes0.059%0.034% Silver Epoxy0.018%0.009% Flash metal0.014%0.006% Solder Resist0.007%0.003% Wire Bonds0.002% Sensor0.338% Epolite Glue0.012%0.006% 2 Bare Hybrids0.198%0.080% 2 Stuffed Hybrids0.386%0.190% Module0.754%0.537% Module Radiation Length13 Decrease of 29%

14. Further Reductions Sensor Thinning – Question of yield, cost Halving reduced stave radiation length by ~20% Copper to AL – Question of yield, cost, producability vs. ~75% reduction?? Reduces stave radiation length by ~5% Reduction of passives – Reduces solder and discretes ASIC thinning – A lot of risk for relatively small rewards Module Radiation Length14

15. Estimates for Material from Power 15 Module Radiation Length DC-DC: 1 converter per module – Estimate 0.23% of a radiation length to stave from converters  33% from SMD capacitors, 27% PCB, 20% shield, 18% custom inductor  Studies are underway to reduce material further  Might be able to use one converter for more than 1 module Serial Power: 1 shunt per ABCN, 1 control and 1 protection ASIC per hybrid – Estimate 0.03% of a radiation length to stave from serial power  Mostly from extra needed hybrid area and AC-coupling capacitors Using currently understanding, the radiation length of material needed to service power has been estimated – Excludes extra bus tape and core material but this should be similar with both serial power and DC-DC convertors 13 mm 28 mm

16. Stave Summary Stave %Xo (NIKHEF08) %X0 (NIKHEF08+correct area/modified X0) %X0(As Built) %X0(As Built W/O Shield) %X0 (130 nm Prediction) Stave Core 0.73% 0.77% (+0.04%) 0.77% (+0.04%) 0.55% (-0.18%) Bus Tapes 0.28% 0.30% (+0.02%) 0.30% (+0.02%) 0.30% (+0.02%) Modules 1.21% (-0.39%) 1.60%1.67% (+0.07%) 1.51% (-0.09%) 1.07% (-0.53%) Adhesives 0.04% 0.06% (+0.02%) 0.06% (+0.02%) 0.06% (+0.02%) Total 2.26% (-0.39%) 2.65%2.81% (+0.15%) 2.64% (-0.01%) 1.98% (-0.67%) Module Radiation Length16 Going to thinned sensor (150 mm thick) will reduce by 0.34% X0 Aluminium hybrid will reduced by 0.09% X0 Bus tape shielding would be other area for improvement not exploited