WP7 ATLAS ID Barrel End Services T.J.FRASER UCL Aim: Using experience gained from work on the current ATLAS SCT Barrel, attempt an improved design and layout of services to minimize mass and enable installation to be carried out more easily. Each update of the CAD drawings is accompanied by an updated excel file showing new mass. At present there are many unknown factors so work has to be very flexible to accommodate new proposals in: ID LAYOUT…….. CRYOSTAT LAYOUT….. STAVE DESIGN….. STAVE SUPPORT… COOLING… READOUT…. POWER…………

TJF Important considerations for engineering design: ID Layout: makes more sense to have all barrels equal length and have each layer equally pitched in R. Decide as soon as possible about services on cryostat – reuse pipes or remove everything and start with a new layout of services. Big impact on cooling layout at barrel end – important for mass and space envelope. Stave design: avoid trailing services beyond the barrel flange (a nightmare on the SCT!) ie ideally have all services connecting at the barrel flange. Include adequate strain-relief for connectors at end – otherwise pull on services could snap integrated stave. Decide if staves are to be removable for reworking – these studies will look at the complexity of work involved in removal after barrel is complete Cooling options – pipe materials - diameters – bending – connector types manifolding – welding etc all impact on end barrel end layout. Readout system and power tapes/cables designs – learn from existing SCT – should be more flexible and easily connected.

5 layers (Strawman layout) Input capillaries to old TRT channels Cooling at barrel end where cooling pipes follow old channels on cryostat : Example shows possible manifolding of pairs of cooling pipes close to the barrel end with each stave on a layer having alternate cooling flow. (supermodule pipe layout) Output cooling to existing cooling channel TJF

No manifolding, cooling pipe positions on stave are as current US stave design Example of cooling distributed evenly on the cryostat - will only work if cryostat is cleared of all old services – manifolding/channeling would have to be done on cryostat or beyond TJF

Barrel end services region - X-section through Z to determine minimum space needed for services envelope (short stave, Strawman)

TOTAL %Xo/side for barrel end services with radial cooling pipe layout and no manifolding in barrel end gap. (Readout not included) COOLING exhaust input connectors BUS cable TJF UPGRADE

Total %Xo/side comparison of end barrel COOLING services only: UPGRADE (radial layout, no manifolding) vs EXISTING SCT EXISTING SCT UPGRADE exhaust input Exhaust UPGRADE input EXISTING SCT connectors TJF