HEP GROUP MEETING work on the ATLAS UPGRADE T.J.Fraser

ATLAS Inner Detector Upgrade summary: Replace the existing TRT, existing SCT Barrel and end caps and pixel detector with possibly 5 barrels SCT and discs at ends, and new pixel detector inside SCT barrels. For the SCT this will mean lots more modules. Modules are at a conceptual stage maybe with hybrid with 40 ASICs connecting to a power bus on the edge. These would operate at high speed using 160MHz clock with serial readout of ABCN but there are various options………eg parallel option clocked at slower 40 MHz. SERIAL POWERING is favoured as in theory it would save a lot of material but this will need serious risk mitigation strategies to protect against failures eg OPEN in serial chain – loss of whole stave!, NOISE, SHORTS etc so must be able to isolate a module. One stave will have 10 modules minimum. Irradiation testing of Readout materials have started, more studies in Module sensors: silicon strip detector specification made, irradiation started, testing from March Date for Final Design Review beginning of 2010 for Barrel followed by Production Readiness Review. Finish production for Barrel modules April LHC SHUTDOWN scheduled for 2015 – 2016 with SLHC running from spring/summer Plan to add early separation dipoles maybe IN detectors at around 6m from IP. Maybe add CRAB CAVITIES at small angle.

ATLAS Inner Detector Upgrade summary: To reach 10, increase beam current or change bunch cross section and crossing angle. RF cavities located around the IP or in 2 locations of the LHC. 25ns spacing versus 50 ns spacing being debated. Radiation: NEUTRON MODERATOR for INNER TRACKER likely – will impact on space envelope inside cryostat. The baseline is 5cm lining the calorimeters. 5cm is a LOT of space but this seems to be the optimum to reduce fluences – but can’t be hermetic – places where services go through prevent this. IP magnets and the ID reach radiation damage limit at 700fb-1 which could be at around 2014 so can’t delay! Various dates on the schedule (rough estimates) are: General TDR (Technical Design Review) 2010 – CONCEPTS FIXED ASSEMBLE PARTS 2011 – 2013 ASSEMBLE STRUCTURES on surface 2012 – 2014 INSTALL IN PIT 2015 STARTUP 2016 SERVICES REVIEW not before March 2008 – lots of work – what services can be reused – reliability – available space. We are setting up a working file for services materials which contains info mass/space occupation etc. 35

ATLAS UPGRADE ID BARREL END REGION TJFraser WP7 meeting Looking at impact of services routing off the barrel end -with current proposed layout of ID….. Looking at Thermal barrier feedthroughs as part of supermodule assemblies Constraints on services – Hot vs Cold gap options

LS LAYERS 1 and 2 R 950, R750, L 3800 SS LAYERS 1, 2 and 3 R 600, R 490, R 380, L 2000

services from inner barrels must route 900mm to outer barrel end

services will line end of short barrels and inner surface of outer layers

services from inner barrel must share space with wheel sections inside outer barrel

Feedthroughs (as part of supermodule assembly, one per supermodule) fit into gaps in the thermal barrier. Layout of gaps would depend on the siting of and shape of the thermal barrier. Shape of feedthroughs would depend on type of services – if LMT type then a rotational aspect could be included. Multi-service feedthroughs like this could only be used if sited close to detector end. Thermal barrier sandwich

Feedthrough – could be designed to come apart or have holes large enough for connectors, with separate seals

services from barrel insulated multi-feedthroughs one per supermodule ‘wheels’ in ‘warm’ gap separate thermal barrier outer barrel inner barrel thermal barrier services separated into groups for channeling WARM

insulated ‘single- service’ feedthroughs ‘wheels’ in ‘cold’ gap. No feedthroughs here but would need patch panels for readout/TTC PCBs somewhere in cold gap. thermal barrier outer barrel inner barrel thermal barrier COLD services from barrel

CONCLUSIONS: GENERAL LAYOUT: Services from barrel on current strawman layout follow a tortuous route – presents mass where not wanted and difficulties of access during and after installation. 5 barrels all the same length would present fewer problems for services and less mass as services gap would be shorter. WARM vs COLD GAP: Warm gap: more space needed for thermal barriers, active cooling pipe insulation and feedthroughs – also means more material where not wanted. Cold gap: services and thermal barriers take up less space and therefore less mass but would still need space for patch panels for some services inside due to limits on lengths and transitions. No insulation needed on cooling (?) Size of single entity – installation difficult if not split up. NUMEROUS POSSIBILITIES (or should this be impossibilities?) for barrel end layouts until basic decisions are made about layout and thermal management.

Barrel services minimum space allocation in Z ‘Strawman’ layout and Spider… layout WARM and COLD GAP versions Services envelope in Z: In order to reserve space allocation - need to use places in the layout where the maximum accumulation of services in Z occur – cannot use an average as it will not be possible to squash services into gaps to equalise the occupation. Need to know which existing services are to be kept and if the existing channels/ducts have to be re-used - before making useful layout in R/PHI for barrel ends. example: x-section in Z for services accumulation, barrels 1, 2 and 3: 29mm thermal barrier & feedthroughs uninsulated cooling pipes & manifolds cooling connectors bus tapes/cables with ‘twist’ factor 84mm TJF

84mm in Z >150mm in R (insufficient clearance) >160mm in Z Barrel services minimum space allocation in Z (‘Strawman’ layout) Z=0 0 B1 B2 B3 B4 B5 How will services from Bs 1,2 and 3 be supported on the inside of B4? Will need separate support cylinder or rings for this, adding to space occupancy and material. Services at barrel ENDS also need supports for connectors/strain relief. COLD GAP version services in Z: bus tapes, connectors, cooling pipes, connectors and manifolds TJF

96mm in Z >162mm in R (insufficient clearance) >172mm in Z Barrel services minimum space allocation in Z (‘Strawman’ layout) Z=0 0 B1 B2 B3 B4 B5 Thermal barrier will need to serve as services support as well – if not, then add this to thickness. Cooling exhaust pipes will need insulation – 6mm thick ie 12mm added here. WARM GAP version services in Z: bus tapes, connectors, insulated cooling pipes, connectors and manifolds TJF

84mm in Z Barrel services minimum space allocation in Z (‘Spider…’ layout) Z=0 0 B1 B2 B3 B4 B5 COLD GAP version 130mm in Z Advantages of simplified barrel layout: avoids two 90 bends in services route just one large services ‘spider’ so can organise services into channels only one type of support needed for connectors/strain relief at barrel ends 0 services in Z: bus tapes, connectors, cooling pipes, connectors and manifolds TJF

96mm in Z Barrel services minimum space allocation in Z (‘Spider…’ layout) Z=0 0 B1 B2 B3 B4 B5 Thermal barrier will need to serve as services support as well – if not, then add this to thickness. Cooling exhaust pipes will need insulation – 6mm thick ie 12mm added here. Not as good as the Cold gap version but better than both Strawman layouts WARM GAP version 142mm in Z services in Z: bus tapes, connectors, insulated cooling pipes, connectors and manifolds TJF

ATLAS Tracker Upgrade - Services at Barrel Ends: Scenario where services are routed through existing services channels on cryostat shown on the next 3 slides ie: Old TRT channels used for fibres, power and sensor cables and input cooling pipes Old SCT cooling exhaust channels used for same purpose in the Upgrade Could possibly work for 108 supermodules (with lots of manifolding for cooling pipes) Wouldn’t work if outer barrels were included – these would need to use existing power cable channels but there would be no space in the existing cooling exhaust channels, so new channels eg one per quadrant would have to be created in order to keep each set together for maximum cooling efficiency. Design of layout on the cryostat is crucial to the design of the layout on the barrel ends!

Evap. cooling routing off barrel end. input exhaust manifold rows per Quadrant: exhaust pipes to ‘old’ cooling channel in cryostat 7 7 input pipes in ‘TRT’ channels (need manifolds) exhaust manifold TJF 28/06/07 half length cooling loops

rows per Quadrant: TJF 28/06/07 exhaust cooling only power and sensor cables go in old TRT channels power and sensor cables in 4 dedicated channels per quadrant shown as one ‘bunch’ per supermodule

rows per Quadrant: TJF 18/07/07 exhaust cooling only power, sensor cables, fibres and input pipes go in old TRT channels optofibre routing: one fibre from each PCB joins one 12 way ribbon: 9 ribbons per quadrant single fibres ribbon four PCBs per supermodule

CURRENT ATLAS SCT BARREL – view of end barrel services for the 4 barrels – these form a dense ‘thicket’ on the barrel ends and beyond. The upgrade will try to avoid this and minimise mass and complexity….however this won’t be easy!

CURRENT SCT BARREL – installation of one barrel inside the others. Silicon modules on cylindrical support cylinder made of carbon fibre. Large services support structure necessary to store long lengths of services and connectors within the profile of the barrel. The services radiating from the barrel on the radial support have to be folded into this structure for integration with the TRT - Transition Radiation Tracker

CURRENT SCT BARREL and TRT being installed in the cryostat in the ATLAS pit. It slides in on side rails. This is the SCT services support structure. The SCT barrel is hidden inside the TRT barrel The orange painted cradle is removed once the SCT is installed.

Conclusion: It has taken over 10 years to arrive at the stage where the Inner Detector is ready to run in the present form with TRT and SCT barrel and end caps all worked on in parallel by different Groups - but there will only be 6 years to produce the Upgrade version, so radical departures in philosophy and design are unlikely to be chosen unless they present a simplification of the current design!