1. ATLAS SLHC UPGRADE ENGINEERING – LIST OF DECISIONS which will affect the design of auxiliary systems layout and routing BASIC LAYOUT FOR BARREL and WHEELS (END CAPS) options: Separation into two combined barrel/wheel entities with separation just off Z=0 Separate single length barrel and wheels ie three entities Separation of barrel in R with outer barrel longer than inner and wheels to fit in ie 4 basic entities leading to: DIMENSIONS of the above and DIMENSIONS of GAPS and ENVELOPES 1 BASIC LAYOUT OF SUPERMODULES ON BARRELS (assumes barrel cylinder support structures) options: 5 barrel cylinders with supermodule rows supported on Outside Diameter 4 barrels, first with rows on OD, second with rows on ID and OD, third with rows on ID and OD, fourth as enclosure only Variations on the above (gives fewer barrels of thicker material) DISTANCE between end detector edge and support cylinder flange in Z TJF 09.07.07

2. ATLAS SLHC UPGRADE ENGINEERING – LIST OF DECISIONS ENVIRONMENT (temperature and humidity) options: One environment for Barrel and wheels with temporary TE ‘door’ for barrel tests in pit before installation of wheels. Barrel and wheels (+pixels) share same environment - needs temporary TE outside pit for testing - if barrel/wheel entities installed together Separate environments for Barrel and Wheels separated by TE barrier. 2

3. ATLAS SLHC UPGRADE ENGINEERING – LIST OF DECISIONS BASIC LAYOUT FOR COOLING options for barrel: Full length supermodule 2000mms: one input and one output with return at end Half length supermodule 1000mms: one input and one output with return at Z=0 THERMAL CONTINGENCY options for barrel supermodules: wiggly pipe along length crossover loop at barrel end ROUTING/MANIFOLDING of COOLING options: Reuse old pipes = lots of complex manifolding Use new pipes – increased numbers possible = less manifolding influences: routing layout at barrel end COOLING PIPE DIMENSIONS (choice of coolant) OD and optimum length of input capillary OD and optimum length of output pipe 3

4. PRESSURE RELIEF VALVES IN A HIGH PRESSURE COOLING SYSTEM options: Before or after detector distance from detector HEAT EXCHANGER options: internal external (could be in input-pipe bundle) INPUT PIPES: (INSIDE TE OR OUTSIDE) cold warm PIPE CONNECTOR TYPE options: …………………. 4 ATLAS SLHC UPGRADE ENGINEERING – LIST OF DECISIONS

5. POWER BUS (ON BARREL) options: integrated ‘stave’ non-demountable detectors with combined power/readout/sensor bus supermodule with demountable detectors but with combined power/readout/sensor bus supermodule as above but with separate power, readout and sensor cable bunches POSITION (ON BARREL) wrt DETECTOR PLANE in R/PHI options: on extension of hybrid in same plane on cover over detector in ‘shadow’ of detector both of the above on support cylinder surface CABLE and CONNECTOR TYPES options: ……………….. 5 ATLAS SLHC UPGRADE ENGINEERING – LIST OF DECISIONS

6. POWER CABLES (OFF BARREL) options: use existing cables use new cables decide amount of space available and where decide to chop old cables where accessible DCS use cables use fibres for readout 6 ATLAS SLHC UPGRADE ENGINEERING – LIST OF DECISIONS

7. CONNECTORS/FEEDTHROUGHS in gap between Barrel and wheels options: No connectors here (material budget) All connectors here Some connectors here, some outside comments: material in gap: even if there are no cable connectors here: still need cooling pipes/cooling pipe connectors and manifolds in this gap still have power/dcs cables in this gap if no readout/TTC PCB here: readout/TTC would still be in cable form rather than fibre form – more material 7 ATLAS SLHC UPGRADE ENGINEERING – LIST OF DECISIONS