ATLAS Inner Detector layout Specifications for thermal screens ANSYS simulations Prototyping and tests results Verificat

1. ATLAS Inner Detector layout • Specifications for thermal screens • ANSYS simulations • Prototyping and tests results • Verifications Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

2. General view of the ATLAS Inner Detector layout Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

3. Heat loads in the ATLAS Inner Detector Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

4. Layout of thermal screens and seals in the ATLAS Inner Detector Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

5. Thermal screen – ANSYS model • Geometry: • Inner radius – 547 mm; outer radius – 555.25 mm • Thickness – 8.25 mm • Length – 1.6 m • Cooling pipe – outer diam. 3.175 mm (56 pipes) • Materials • Insulation – conductivity 0.046 W/mK (including radiation damage) • Outer and inner surface -aluminium foil with thickness 0.05 and 0.15 mm respectively • Cooling pipe – aluminium • Boundary conditions • Temperatures: outside 15 °C; inside -7 °C • Convection: HTC 5 W/m2K on both surfaces • Convection inside the cooling pipe: 1100 W/m2K • Temperature gradient along the cooling pipe: 2K (-10 to -8 °C) Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

6. Thermal screen – ANSYS results Heat generation: 750 W for 15 °C outside Would be 865 W for 20 °C outside Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

7. Thermal screen – ANSYS resultstemperature distribution Temperature distribution along the inner surface of the model Temperature distribution along the outer surface of the model Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

8. Figure 7. Temperature distribution in the model with a 4mm insulating gap filled with CO2 Thermal screen – ANSYS modelversion with gas gap Geometry like for previous model with different thickness and insulating material Two CFRP plates with 4 mm CO2 insulation between them Heat generation 750 W (radiation between two surfaces not included into ANSYS model) Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

9. Figure 8. Temperature distribution in the inner surface of the model insulated with CO2 Figure 9. Temperature distribution on the outer surface of the model insulated with CO2 Thermal screen – ANSYS model version 2 , temperature distribution Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

10. RAL – prototype of thermal screen, general view Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

11. RAL – prototype of thermal screen inner and outer surfaces Internal surface with cooling pipes External surface with heaters Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

12. RAL – prototype of thermal screen preparation for the tests Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

13. Thermal screen – small prototype for heat transfer measurements Ext. surface mean temp. ~23 °C Int. surface mean temp. ~8.7 °C Conductance between CFRP planes = 0.084 W/K For whole thermal screen heaters will dissipate 980 W Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

14. ATLAS Inner Detector Thermal Screen summary • Inner Detector layout is very complicated from the thermal management point of view • Many separated volumes with different operating temperatures and environmental gases • Lack of space and material budget force us to use active thermal screens with very aggressive solutions • Thin insulation • Small diameters of cooling pipes • Biggest worries • All feedthroughs for cables, pipes etc. • Purging gas its flow and pressure control • Dew point and humidity control Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI