JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI  ATLAS Inner Detector layout  Specifications for thermal screens  ANSYS simulations  Prototyping and tests results  Verifications

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI General view of the ATLAS Inner Detector layout

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI Heat loads in the ATLAS Inner Detector

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI Layout of thermal screens and seals in the ATLAS Inner Detector

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI Thermal screen – ANSYS model Geometry: Inner radius – 547 mm; outer radius – mm Thickness – 8.25 mm Length – 1.6 m Cooling pipe – outer diam mm (56 pipes) Materials Insulation – conductivity 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/m 2 K on both surfaces Convection inside the cooling pipe: 1100 W/m 2 K Temperature gradient along the cooling pipe: 2K (-10 to -8 °C)

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI Thermal screen – ANSYS results Heat generation: 750 W for 15 °C outside Would be 865 W for 20 °C outside

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI Thermal screen – ANSYS results temperature distribution Temperature distribution along the inner surface of the model Temperature distribution along the outer surface of the model

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI Thermal screen – ANSYS model version with gas gap Figure 7. Temperature distribution in the model with a 4mm insulating gap filled with CO 2 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)

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI Thermal screen – ANSYS model version 2, temperature distribution Figure 8. Temperature distribution in the inner surface of the model insulated with CO 2 Figure 9. Temperature distribution on the outer surface of the model insulated with CO 2

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI RAL – prototype of thermal screen, general view

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI RAL – prototype of thermal screen inner and outer surfaces Internal surfacewith cooling pipes External surface with heaters

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI RAL – prototype of thermal screen preparation for the tests

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI 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 = W/K For whole thermal screen heaters will dissipate 980 W

JCOV, 25 OCT 2001Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI 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