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 tobe very flexible to accommodate new proposals in:

ID LAYOUT…….. CRYOSTAT LAYOUT….. STAVE DESIGN….. STAVE SUPPORT… COOLING… READOUT…. POWER………….

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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 pipesor remove everything and start with a new layout of services. Big impacton 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 atthe 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 willlook at the complexity of work involved in removal after barrel is complete

Cooling options – pipe materials - diameters – bending – connector typesmanifolding – welding etc all impact on end barrel end layout.

Readout system and power tapes/cables designs – learn from existingSCT – should be more flexible and easily connected.

5 layers (‘Strawman layout’)

Input capillariesto 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 thebarrel end with each stave on a layer having ‘alternate’ cooling flow.(supermodule pipe layout)

Output coolingto existing cooling channel

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No manifolding,cooling pipepositions on stave are ascurrent USstave design

Example of cooling distributed evenly on the cryostat - will only workif cryostat is cleared of all ‘old’ services – manifolding/channeling would have to be done on cryostat or beyond

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TJF 080708Barrel end services region - X-section through Z to determineminimum space needed for services envelope (short stave, Strawman)

Total %Xo/side

SSBus Backing

SSShield

SSepoxy

SStracks

LSBus Backing

LSShield

LSepoxy

LStracks

endpipe no M

endpipeconnect

endcapillaries

capillconnect

TOTAL %Xo/side for barrel end services with radial cooling pipe layoutand no manifolding in barrel end gap. (Readout not included)

COOLING

exhaust

input

connectors

connectorsBUS cable

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UPGRADE UPGRADE

Total %Xo/side comparison SCTvsUPGRADE

endpipe no M

endpipeconnect

endcapillaries

capillconnect

NOWspiders

NOWcapillaries

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

EXISTING SCTUPGRADE

exhaust

input

Exhaust

UPGRADEinput

EXISTING SCT

connectors

connectors

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