Contents Jason Tarrant STFC Aim of Presentation to show: l Problem of compressors located at south shield wall l Description of compressor layout and services routing at west wall l Work involved

Current Compressor Location Current Proposed Compressor Position Under South Mezzanine Water and power services already installed for compressors South shield wall

Magnetic Field Analysis Magnetic Field Plots for Step IV & VI Around South Shield Wall Area (V Bayliss CM33) Step IV Step VI Level requires 5 mm Fe / 1 mm mumetal shielding

Magnetic Shielding of Compressor Magnetic Shielding Cabinet for Compressor as South Shield Wall Location Labyrinth cable entry/exit 5 mm Iron + 1 mm mumetal Compressor Only suitable for Step IV at west end of the South Mezzanine, Step VI magnetic field too strong £11,500 – £13,000 each! 19 Compressors (IV) = £218k (~$350k) min.

Current West Wall Layout Current West Wall Configuration West End Stairs Services Distribution Panel West Wall North Mezzanine

Current West Wall Layout Area at West Wall for Device Assembly & Preparation Potterax Door Assembly & Preparation Area Installation Path Spectrometer Solenoid with Tandem Lifting Beam (at crane extent) Beam dump

Proposed Compressor Layout Provisional West Wall Compressor Layout (J Webb) Compressor spacing allows ‘transplant’ of existing services to west wall with minimum of reconfiguration or manufacture of new services runs

Compressor Line Routing Different Routing Layouts l Cryomech 40 m (purple) / Sumitomo 30 m (yellow). Adv = Only 4 x Sumitomos crossing main assembly area. Disadv = 4 x Sumitomos crossing assembly area. Cryomechs at 40 m (30 m max w/o losses). Hoses connected on north side in way of moving platforms (hence alternative red hoses shown). l Cryomech 35 m (green) / Sumitomo 30 m (yellow). Adv = Cryomech hoses closer to 30 m. Disadv = Most hoses cross assembly area, require false floor. l Cryomech 30 m(black) / Sumitomo 30 m (white). Adv = Cryomech & Sumitomo at preferred length. They are not routed across the assembly area. Disadv = Cryomech hoses will have to form bridge over ‘landing’ just inside Potterax door. Full West Mezzanine required to move 6 Step IV compressors to south side.

Proposed Step IV Scheme Proposal for Step IV Compressor Layout at West Wall West wall mezzanine Sumitomo hose for Tracker cryo (max 28.5m) Services bridge Alternative position for stairs Cryomech hose for device cryo (max 28.5m)

Proposed Step IV Scheme SPECTROMETER SOLENOID AND TANDEM LIFTING FRAME STAIRS NEED TO BE REMOVED TEMPORARILY WHEN DEVICES ARE TO BE MOVED INTO COOLING CHANNEL DEVICES WILL NEED TO BE ROLLED INTO HALL PAST SERVICES BRIDGE UPON DELIVERY BEAM DUMP

To Do To Investigate l Ensure magnetic field is low enough not to affect compressors in west wall position l Can all cold heads / compressors accept an extra few metres of line temporarily, i.e. when devices pulled off-line on moving platforms (non operational – keep cold e.g. <50 ºK) l Ensure assembly area is big enough and that stairs & services bridge are compatible with device assembly and installation To Design l Optimise routing & length of hoses and power cables from compressors to cryo-heads etc to minimise excess. l Structure to manage 38 to 62 relatively large and stiff hoses + power services l West mezzanine and stairs

To Do l Installation l Remove current stairs & PPS cage l Install west mezzanine platform, stairs & new PPS l ‘Transplant’ services from south mezzanine l Reroute water feeds l Install services management & compressor supports l Fit compressors l Run hoses & power to devices as required

Finally Conclusion l 30 m hoses (no performance losses) can be run from west wall to devices with minimal compromise (reduced assembly area) l Compressor layout (with mezzanine) allows easy & safe access to 2x high compressors l Structural work (mezzanine, stairs, PPS) significant but not expensive in comparison to 19x compressor magnetic shielding cabinets l Capacity in solution for Step V & VI compressors l If magnetic fields turn out to be too high at any step on west wall and there are no other solutions then magnetic shielding may be implemented in this configuration