Strawman module design

VELOPix module VELOPix: Pixel readout chip based on medipix/timepix 256 x 256 pixels 55 mm square. Chip is 3 side buttable Small pixel cell means that single sided modules can be built By using TSV (through silicon vias) dead side can be reduced to 0.8 mm in Medipix3 Analogue power consumption 6 mW per pixel. 4 bit equivalent ADC resolution provided via TOT Upgrade being considered to 90 nm technology (power consumption and radiation hardness benefits) 14100 14100 800 Medipix3 Chip dimensions 2 2

U-shape VELOPix Module Layout 50 mm Al ground plane behind diamond power tape connector inactive part of chip Region of 800x55 mm pixels metallisation on diamond 3 windows in diamond for bonding through to TSVs guard rings 3

Cross section of central part of 2 chip assembly window in diamond wire bonds power tape 200 mm diamond 50 mm Al ground plane bump bonds glue 150 mm ASIC interposer 150 mm silicon 55x55 mm pixels 800x55 mm pixels under inactive part of chip TSVs Key points of design: Full efficiency for first measured point reduced resolution in 5% of active area TSVs an essential feature Diamond metallisation and laser cutting has been achieved by other collaborations but remains to be proven for LHCb -edgeless technology would remove the 2% remaining dead area between silicon pieces - Semi tiled solution: minimise dead regions 4

readout Vacuum tank average particle rate per bx and 1.4 3.1 5.8 10.9 1.7 3.7 4.6 8.8 0.9 2.3 1.3 3.0 7 mm LHC beam average particle rate per bx and average data rates (Gbit/s) for the Velopix asics, at the highest luminosity (L=20*1032/cm2/s) and with an average cluster size=2 20 x Differential copper links ~ 2m 20 x optical links ~60m vacuum feed-throughs Electro-optical Tell 40 Network interface Vacuum tank

Many many other issues Optimal number of modules/stations Sensor technology Paddles Base and movement system RF foil Material choices Single sided -> CTE is very important Gluing Radiation hardness Vacuum compatibility Powering / biasing Hybridisation / routing And this is only the tip of the iceberg…..

z of first measured point (compared Material Estimate: 150 mm silicon + ASIC ~ 0.3% 100 mm Aluminium ~ 0.2% 200 mm Diamond ~ 0.2% TOTAL ~0.7-0.8% per station (single layer) - 8W per station Simulating 21 stations as current VELO gives satisfactory hit distributions z of first measured point (compared to VELO with inner radius of 8 mm..) Number of hits per track 8 8