ATLAS TRT CO 2 cooling system project status Beaufort 12: “Hurricane” (>119 km/h) Saffir-Simpson 5: “catastrophic damage” (>250 km/h) (CO 2 distribution system: up to 300 km/h & Re = ) Joël Grognuz,

TRT CO 2 cooling system status, Joël Grognuz Wheels manifolds optimization Wheels manifolds optimization  24% maximum flow variation   See: ATL-INDET Pressure drop calculations Pressure drop calculations  1 bar in total; 0.5 to 1.5 bar(abs) at inlet and outlet of the pump. inlet and outlet of the pump. System requirements: frozen System requirements: frozen see see Components procurement Components procurement  Offers for Key components: pump, valves (No EV => no shielding needed)  Most hardware components identified, budget done  Prototype passive safety valves built Final 2 nd prototype layout Final 2 nd prototype layout  Functionalities, regulation and safety strategy defined  Like layout of the final system with two mock-ups (C-wheels) instead of 6 groups of wheels, might simplify 2 nd mock-up depending on manpower. Summary of last achievements, status

TRT CO 2 cooling system status, Joël Grognuz USA 15 ULX 16, pipes already installed gas room pump C-side A-side Racks UX Final system:

TRT CO 2 cooling system status, Joël Grognuz Prototype layout 4 states: -purge -turn on -run -emergency turn off

TRT CO 2 cooling system status, Joël Grognuz Limit for detector C: Passive safety over- pressure valve opens C: Trigger for active safety C: active valves in p stabilized by passive valves Worst case if blockage on the lines: Safety: (end-caps stand up to ± 5.5 mbar relative to ID volume) Passive safety valves:Fast active safety valves: opens at ± 4 mbar, fully opened at ± 5 mbar reaction times: opens at ± 4 mbar, fully opened at ± 5 mbar reaction times: whole system: < 500 ms whole system: < 500 ms valve: 100 ms valve: 100 ms For C-wheels with active safety: 10 liters sent to ID volume If constant flow of ±75 m 3 h -1 in ID (additional active safety failure): +3.4/ -2.2 mbar difference in ID (4 mbar allowed) (ID safety meeting next week) fast release pneumatic control safe position 180 mm Fits in membrane envelope

TRT CO 2 cooling system status, Joël Grognuz Failure modeling with simulink Volumes: C: 0.7 m 3 B: 1.5 m 3 A: 0.8 m 3 ID: 2 m 3 Volume element: uses Kv formula for valves and ideal gas assumption Laplace transform allows to solve differential equations to give time evolution

TRT CO 2 cooling system status, Joël Grognuz Failure 1: 300 m 3 h -1 line blocked Syst. off

TRT CO 2 cooling system status, Joël Grognuz Failure 2: 75 m 3 h -1 line blocked Still safe in case of active safety failure (assuming that regulations on other wheels stand the pressure changes in the ID)

TRT CO 2 cooling system status, Joël Grognuz Failure 3: 2 x 75 m 3 h -1 line blocked Almost as dangerous as 300 m 3 h -1 case because half of the flux but also half of the volume until other passive safety valves open!

TRT CO 2 cooling system status, Joël Grognuz Cleanliness Pump: (contains 1L of oil) Pump: (contains 1L of oil)  Strong candidate found with double joints and gas barrier between gear box and system. (supplies 270 nm 3 h -1 with calculated pressure drops)  Can use Si-free oil with low vapour pressure in the gear box (<10 -6 Torr at working Temperature). Other components: Other components: lubricants allowed, no numbers exist!

TRT CO 2 cooling system status, Joël Grognuz Tightness The requirement for N 2 content < 1% means that the low pressure side of the system has to be tight; any air leak rate will have to be compensated by a CO 2 purge 100 times larger! (problem of cost) The requirement for N 2 content < 1% means that the low pressure side of the system has to be tight; any air leak rate will have to be compensated by a CO 2 purge 100 times larger! (problem of cost)

TRT CO 2 cooling system status, Joël Grognuz Group of wheels mock-up 0.9 m 3, can be reduced by adding volumes inside. 0.9 m 3, can be reduced by adding volumes inside. C-wheels: 0.7 m 3 A-wheels: 0.8 m 3 B-wheels: 1.5 m 3 2 separations 2 separations 0.7 mbar pressure drop 0.7 mbar pressure drop 1 m 6 m 0.15 m Inlet manifold holes (80 holes) Outlet manifold holes (96 holes) Passive safety valves

TRT CO 2 cooling system status, Joël Grognuz Schedule  Accept budget (possible delay)(February)  Clarify manpower availability for prototype building  Start procurement (March)  Build “Prototype” (main circuit, at least one full rack, detector mockup, control unit) (June)  If time, simulate the prototype and the full system  Test prototype (July)  Risk analysis (led in parallel)  PRR (September)

TRT CO 2 cooling system status, Joël Grognuz Budget Summary with possible options: (piping and operation costs for final system not included)