1. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI1 FMD: Silicon multiplicity detectors Thermal simulation meeting, CERN, 11 November 2002 Børge Svane Nielsen Niels Bohr Institute 1.Geometry of FMD, T0 and V0 detectors 2.Material constants for FMD 3.Heat dissipation of FMD

2. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI2 FWD detectors layout

3. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI3 Si1, T0_r & V0_r layout

4. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI4 Si2 layout

5. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI5 Si3, T0_l & V0_l layout

6. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI6 CERN maquette 1:1 Si1 (inner)Si1(outer) V0-R T0-R Absorber ITS-pixels

7. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI7 FMD ring layout 256 Inner: Rin=4.2 cm Rout=17.2 cm Outer: Rin=15.4 cm Rout=28.4 cm 20x2x128=5120 10x2x256=5120 128 Full FMD = 3 inner rings + 3 inner rings + 2 outer rings 2 outer rings

8. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI8 Si1 assembly Si detectors Support plates Read-out electronics card on support plate back side

9. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI9 Hybrid with Viking chips VA preamp+shaper: 128 ch Connector(s) for power, control, read-out Other components Hybrid cards contain:  FE chips  Bias voltages distribution  Gate/strobe distribution  Read-out clock distribution  Detector bias connection Read-out cards contain:  Bias voltages generation  Gate/strobe distribution  Read-out clock generation  Remote connections Si detector

10. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI10 FMD Material constants Material type and thickness of one Si detector ring: LayerMaterialThickness Heat conductivity (W/m·K) Density (kg/m 3 ) Specific heat (J/kg  K) Silicon detector Si0.3 mm842330678 Hybrid Al 2 O 3 0.5 mm353970880 FE electronics air + chips 10 mm (mostly air) Support Carbon fibre or aluminium honeycomb 2  0.5 mm C or Al + 10 mm air C: 24 Al: 222 C: 2200 Al: 2700 C: 691 Al: 900

11. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI11 FMD Material constants Material type and thickness of one Si detector ring: LayerMaterialThickness Interaction length Radiation length Silicon detector Si0.3 mm0.6 · 10 -3 0.3 · 10 -2 Hybrid Al 2 O 3 0.5 mm2.0 · 10 -3 1.0 · 10 -2 FE electronics air + chips 10 mm (mostly air) Support Carbon fibre or aluminium honeycomb 2  0.5 mm C or Al + 10 mm air C: 2.6 · 10 -3 Al: 2.5 · 10 -3 C: 0.5 · 10 -2 Al: 1.1 · 10 -2 Total thickness of one Si ring: C: 5.2 · 10 -3 I 1.8 · 10 -2 X 0 Al: 5.1 · 10 -3 I 2.4 · 10 -2 X 0

12. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI12 FMD electronics FMD channel count Note: We are looking into increasing the number of strips, but use more integrated FE chips - red values. In the following, I assume the new numbers. Segments (wafers) Phi sectors Radial sectors Hybrids Chips/ hybrid FE chipsFE channels Si1 inner1020(256) 51210(16) 8(160) 80(5,120) 10,240 Si1 outer2040(128) 25620(8) 4(160) 80(5,120) 10,240 Si2 inner1020(256) 51210(16) 8(160) 80(5,120) 10,240 Si2 outer2040(128) 25620(8) 4(160) 80(5,120) 10,240 Si31020(256) 51210(16) 8(160) 80(5,120) 10,240 Total system7014070(720) 360(25,600) 51,200

13. Thermal simulation, CERN, 11 Nov 2002Børge Svane Nielsen, NBI13 Heat dissipation Heat dissipated by FE electronics of one Si detector ring: VA1TA preamp chip (128 channels): 150 mW  80 chips = 12 W / ring For simulation: assume uniform distribution on hybrid surface (towards support plate) Read-out electronics and power distribution:  5 W / ring For simulation: assume concentrated in 2 locations near outer radius