NEW SMALL WHEEL DESIGN DESCRIPTION OF THE DESIGN AND REASONS BEHIND THE CHOICES Pictures and sketches: Courtesy of Tatiana Klioutchnikova and Giancarlo Spigo

The increased energy foreseen for Run 2, and the increased luminosity foreseen for Run 3 (well above the project luminosity) are not compatible with the actual Small Wheel muon detectors. For this reason a New Small Wheel (NSW) detector will replace the current Small Wheel starting from Run 3. This means the installation on both sides must be completed during LS2 ( ). The NSW will have a similar shape and approximately the same location (between the ECT and the ECC) compare to the actual one, but it will be very different in the conceptual design due to different constraints. The major constraints are the following: New Small Wheel 02-Dec-2014NSW design2

a)The sectors (MM and sTGC wedges) are thicker than the current EIL/EIS chambers and their overall load is more than threefold higher (around 160 kN or more). b)Muon detector composed of full monolithic sectors (increased bending moment and, therefore, deformation due to the concentrated loads transmitted by the sector KM supports to the NSW mechanical structure) c)Two azimuthal sets of alignment bars (16 in total) d)The manipulation of the JD-NSW must be made with only a 140-t crane e)No overlapping coverage degradation (very tight spaces for sector insertion) f)Reduced longitudinal envelope than today (55 mm space sold to LAr) f)The complete NSW (mechanical structure, alignment bars and Sectors) must be assembled and solidly linked to the JD shielding on surface (building 191) and the whole complete assembly lowered down in the cavern as today. Constraints 302-Dec-2014NSW design

In the last several months, it has been concluded that merging both JD and NSW structures could be the remedy for the majority of the conflicting issues: 1.The structure results more compact to fulfill envelope needs 2.It is lighter for a better manipulation 3.It is more rigid to limit the deformations due to the increase of sector weight and bending due to more concentrated sector loads During last design review (05/09/2014) it has been presented the New JD which has been conceived in such a way that it becomes part of the structure. The NSW is permanently attached to the New JD surface and the feet (sustaining the whole assembly) are integrated in the NSW mechanical structure, so that the stress is shared between the two objects. Why a New JD? 02-Dec-2014NSW design4

New JD + NSW The New JD is made out of steel, while to limit the weight, the NSW structure is composed of aluminum tubular profiles that are connected together by means of inserts. This structure is fixed to the NJD with screws. For sake of rigidity, austenitic steel is used in the feet region. This permits a reduction of the whole assembly global deformation by one third. 02-Dec-2014NSW design

The NSW project started several years ago. Lots of things have been done so far, but many others need to be studied and designed. For the moment the people involved have been: Giancarlo, Marco, Julien, Tatiana and Jamie In the near future, most of the ATLAS Project Office will be involved into this project: Raphael, Michel, Aimilianos, Alexandre, Vit, Augusto, Fred, Cedric, Gevorg, Tomasz A reductive and not exhaustive list of the things that still have to be done is the following What else need to be done? 02-Dec-2014NSW design6

FEA calculations (NSW and New JD bolted connections, weldings, NSW seismic, tooling, etc.) Infrastructure – Layout study for assembly of New JD and NSW sectors (available space in bldg. 191 and 180) – Cranes manoeuvring limits analysis – Availability analysis of the necessary space for storage during assembly (material displacement? What? Where?) – Possible (needed?) reconfiguration of bldg. 191 (ECT cantilever removal) Sectors assembly – MM Spacer frame design – Assembly study of MM wedges with spacer frame and tooling – MM Assembly location at CERN (Clean room bldg. 180 reconfiguration) – MM and sTGC storage (space availability and needed tooling) – MM and sTGC wedges assembly in final sectors (study, space availability and needed tooling, etc.) Things to do 02-Dec-2014NSW design7

Survey of mechanics and sector positioning procedures Study and optimization of the JD vertical assembly – Attachment to the concrete-blocks wall – Tooling for the various JD parts (including shieldings) Study and optimization of the services (cables, pipes, etc.) – Cable trays routing and layout on JD (surface and outer radius) – Patch panels design and connection (in situ) procedure – Impact on cable schleps (flexible chains) Study and optimization of the NSW vertical assembly – Tooling for the Hub/Plug – Revision of the actual “WISCONSIN” tooling – Small sector spoke grabber – Large sector spoke grabber – New “WISCONSIN” tooling – Special feet Grabber – Small Sector grabber – Large Sector grabber Things to do 02-Dec-2014NSW design8

A-plate insertion tooling Lifting/Lowering tooling modifications Transportation tooling – Cover – Heating system (?) – Truck Transportation procedures – Analysis of problems along the path (tram lines, internal obstacles, SX1 door, etc.) – Analysis of SX1 environment (maximum height of the crane, storage position, etc.) Lowering and sliding procedure – Revision of the movement system – Locking system Things to do 02-Dec-2014NSW design9

BACK-UP SLIDES 02-Dec-2014NSW design10

As sectors are thicker than the EIL chambers (410 mm with respect to 367 mm), the key approach that has been pursued in order to get more longitudinal space is the reduction of the JD thickness associated with the complete redesign of the vertical shielding implying a different sandwich of materials and a drastic thickness reduction. Thicker Sectors 11 Actual SW EIL chambers 367mm 410mm 210mm NSW Large Sector sTGC MM Spacer frame MM 02-Dec-2014NSW design

No overlapping coverage degradation (very tight spaces for sector insertion) Overlapping 12 SS overlapping LS overlapping LS SS 02-Dec-2014NSW design

Constraints 13 Reduced longitudinal envelope than today (55 mm space sold to LAr) 02-Dec-2014NSW design Global Envelope (+ 32 mm for global assembly tolerance, adjustment, positioning) New Small Wheel Nominal dimensions 1058 mm 20 End Cap Toroid End plate Real position Z 7931 End Cap Toroid Global envelope Z New Small Wheel Nominal limit Z New Small Wheel Global/Individual envelope Z 6810 LAr cryostat HO face Real position Z mm – request for the Lar Upgrade ( space between warm and cold vessel) 55 Z 6782 IP HO 8 LAr envelope Z R 850 clearance 20 clearance + 8 mm – cooling for beam pipe New Small Wheel Global envelope Z mm

Z - ENVELOPES (11/07/2014) 02-Dec-2014NSW design14 32 – envelope value: 15 manufacturing/assembly tolerances + 7 maximum deformation + 10 adjustment/positioning POLYBORON LEAD RETURN FLUX RING LAr CALORIMETER HUB IRON SHIELDING SECTORS A-PLATE (additional support) 47 – envelope value: 15 manufacturing/assembly tolerances + 15 maximum deformation + 17 adjustment/positioning TGCTGC MM TGCTGC SECTOR GLOBAL ENVELOPE

The New JD will be made of steel as the actual one. Its thickness reduction has a quite mild effect on solenoid magnetics. New JD 02-Dec To avoid problems, the New JD thickness in the return flux zone, has the original thickness (80 mm). The central part, instead, is thinner to accommodate the tagger detector for the High  detection. NSW design Inner JD disk 90mm thick Inner JD disk 90mm thick Main JD disk 40mm thick Main JD disk 40mm thick New return flux ring zone 80mm thick New return flux ring zone 80mm thick Overlapping zone for bolted joint View from IP Inner JD disk 90mm thick (50mm in the overlap) Inner JD disk 90mm thick (50mm in the overlap) View from HO 80 = = R R R R. 430 R R Slot for tagger (high  detector) 40mm thick

New JD Since the New JD will be rigidly connected to the structure (unlike the current one it cannot be separated from the structure) it must have windows to access the Alignment bars and the Small Sectors Kinematic Mounts of IP side. This windows will be closed with caps once the alignment is done 02-Dec-2014NSW design16

New JD Vertical assembly 02-Dec-2014NSW design17 12 Parts design

Hub+Plug installation 02-Dec-2014NSW design18

NSW Vertical assembly 02-Dec-2014NSW design19

FEA CALCULATION 02-Dec-2014NSW design20 The analysis has been performed using ANSYS R15.0 with the following conditions: 1.Bottom surface of each foot is entirely bonded to the New JD bottom plate (above the shoes) 2.New JD bottom plates are constrained in order to avoid displacements in Y and Z 3.Standard Earth gravity is acting on each part vertically (no ATLAS 0.708° slope has been considered) 4.Load due to each sector has been replaced by two or three local forces (depending on the sector) on the structure spokes

Small Sectors loads 02-Dec-2014NSW design21 SMALL SECTORS ESTIMATED WEIGHT - 8 kN or

Large Sectors loads 02-Dec-2014NSW design22 LARGE SECTORS ESTIMATED WEIGHT - 12 kN or

Inner pipe of the feet in austenitic steel and all the rest in aluminum. New JD disk 40 mm thick FEA RESULTS – disk thickness 02-Dec-2014NSW design23 Max deformation towards HO: 23.7 mm Reducing the thickness of the main disk from 50mm to 40mm, does not affect sensibly the deformation of the whole assembly Inner pipe of the feet in austenitic steel and all the rest in aluminum. New JD disk 50 mm thick Max deformation towards HO: 23.4 mm

Inner pipe of the feet in austenitic steel and all the rest in aluminum. New JD disk 40 mm thick. New JD bottom plate laying on ATLAS rails (compression only) Inner pipe of the feet in austenitic steel and all the rest in aluminum. New JD disk 40 mm thick. New JD shoes laying on ATLAS rails (compression only) FEA RESULTS – boundary conditions 02-Dec-2014NSW design24 Max deformation towards HO: 28.8 mmMax deformation towards HO: 29.5 mm Removing the boundary condition mentioned in point 1 of slide 10 (bonded surfaces of New JD plates), increases the deformation by nearly 20%. Taking into account the New JD shoes increase further the deformation by 2.5%

FEA RESULTS – A-plate The deformation along Z is reduced by nearly 65%. Therefore this A-plate is definitely necessary to limit the deformation to a reasonable one and it has been added to the design 02-Dec-2014NSW design25 To reduce the deformation a 15mm thick plate can be added HO side. This A-plate is attached to the hub on the top, along the LS spokes in the middle and on the New JD feet on the bottom. Max deformation towards HO: 10.3 mm Inner pipe of the feet in austenitic steel and all the rest in aluminum. New JD disk 40 mm thick. New JD shoes laying on ATLAS rails compression only) A-Plate (15mm)

To further reduce the overall bending and, then, gain some space to better locate the NewJD- NSW assembly in the envelope, the whole structure may be designed and built with a counter- deformation that can fully or partially compensate the bending deformation improving both the longitudinal clearance and the sector positioning. NSW+NewJD counter-deformation 02-Dec-2014NSW design26 The counter-deformation could be obtained either adding an angled shim or machining the top face of the New JD shoes with a proper angle Angled shim

All spokes in aluminum New JD disk 50 mm thick Inner pipe of the feet in austenitic steel and all the rest in aluminum New JD disk 50 mm thick FEA RESULTS – feet material 02-Dec-2014NSW design27 Max deformation towards HO: 32.3 mmMax deformation towards HO: 23.4 mm 23.4mm towards HO 3.7mm towards IP Changing the material of the inner pipe from aluminum to stainless steel reduces sensibly the deformation of the whole assembly

Inner pipe of the feet in austenitic steel and all the rest in aluminum. New JD disk 50 mm thick Feet in austenitic steel and all the rest in aluminum. New JD disk 50 mm thick. FEA RESULTS – feet material 02-Dec-2014NSW design28 Max deformation towards HO: 23.4 mmMax deformation towards HO: 17.9 mm Changing the material of most of the feet from aluminum to stainless steel reduces sensibly the deformation of the whole assembly, but it increases the weight of each foot from 670kg to 1000 kg

LARGE SECTORS MM ( 2 wedges + frame + electronics + services) 450 kg (courtesy of P. Iengo) TGC (2 wedges) 500 kg (courtesy of G. Mikenberg) Services out of chambers 150 kg (courtesy of A. Lanza) TOT1100 kg  1200 kg SECTORS WEIGHTS These loads are used for the FEA calculation (see next slides). They should not be too far from reality, but they might be slightly underestimated. In this case the performed analysis might be not conservative. 02-Dec-2014NSW design29 SMALL SECTORS MM ( 2 wedges + frame + electronics + services) 320 kg (courtesy of P. Iengo) TGC (2 wedges) 320 kg (courtesy of G. Mikenberg) Services out of chambers 150 kg (courtesy of A. Lanza) TOT 790 kg  800 kg

New JD-NSW WEIGHTS 02-Dec-2014NSW design30 1×New JD (main disk 40mm, central disk 90mm, outer crown 80mm) kg 1×Return flux segments and ring 3250 kg 1×Assembly center tube (inner brass plug + outer steel cylinder) kg 1×Hub (brass) 7950 kg 1×Polyboron + lead shielding (vertical HO) 1060 kg 1×Polyboron + lead shielding (hub) 600 kg 1×Polyboron + lead shielding (vertical IP) 2000 kg 6×SS spokes 6× 240 kg 1440 kg 2×Feet spokes 2× 680 kg 1360 kg 8×LS spokes 8× 350 kg 2800 kg 32×Spokes joints32× 6 kg 200 kg 16×Alignment bars16× 40 kg 640 kg 8×Small Sectors 8× 800 kg 6400 kg 8×Large Sectors 8× 1200 kg 9600 kg Services (25% of sector weights) 4000 kg Fasteners 500 kg Contingency 4350 kg 1×A-plate (15mm thick) 2000 kg TOT kg

WEIGHTS TABLE As shown in the table, according to the loads estimation, the total weight of the New JD-NSW is lower than the actual JD-SW one. Furthermore a further reduction in weight is foreseen by revising the lifting tooling 02-Dec-2014NSW design31 Parts / Components Current Small Wheel + Current JD [kg] New Small Wheel + New JD [kg] Lifting beam (palonnier) (1) Lifting frame (2) Additional beams (3) 2150 Scaffolding900 Lifting cylinder (4) 2100 Airpads3200 Assembly center tube (plug + nose) (5) JD cone (6) 7900 TGCs1700 JD disk (disk + feet + segments) (7) SW (Hub + structure + chambers)20000 Everything else (fasteners + weldings + services + …)4350 Crane hook and cables3500 JD-SW (real weight measured during lifting operation) New JD (main disk 40mm thick) Return flux segments and ring3250 Polyboron + lead vertical shielding HO side 1060 Polyboron + lead hub shielding 600 Polyboron + lead vertical shielding IP side (JD-Lar) 2000 Hub 7950 SS spokes 1440 Feet spokes (Inner pipe of the feet in st steel and all the rest in Al) 1360 LS spokes 2800 Spokes joints 200 Alignment bars 640 Small sectors 6400 Large sectors 9600 Services (25% of sector weights) 4000 Fasteners 500 A-plate (15mm thick)2000 New JD-NSW estimated weight Additional 1000kg for the stiffer feet (see slide 15)

1.According to: ATLJD___ According to: ATLJD___ According to: ATLJD___ According to: ATLJD___ According to: ATLJD___ According to: ATLJD___0066, ATLJD___0067, ATLJD___0068, ATLJD___0069, ATLJD___0070, ATLJD___0071, ATLJD___0148, ATLJD___0149, ATLJD___ According to: ATLJD___0101, ATLJD___0146 REFERENCES 02-Dec-2014NSW design32

55mm LAR extension 02-Dec-2014NSW design33 LAR will extend their envelop 55mm towards HO up to 850mm from beam axis

Individual Envelope definition Nominal dimensions + manufacturing/assembly tolerances + maximum deformation Global Envelope definition Individual envelope + global assembly tolerance (when applicable**) + positioning and adjustment tolerances (to be worked out ENVELOPES **If JD + sectors are considered as one assembly, the global assembly tolerance already taken into account in the individual envelope is not applicable. Therefore in this particular case is not applicable 02-Dec-2014NSW design34

Services envelope on top of ECT 02-Dec-2014NSW design35 Large sector ECT Bolts Z envelope 15mm Pipe Large sector Magnetic field measurement sensor, Z envelope 20mm This slide explains the 20mm for the End Cap Toroid Global envelope (Z 7910) presented in slide 5 See next slide for pictures

Services envelope on top of ECT 02-Dec-2014NSW design36 Magnetic field measurement sensors, Z envelope 20mm Bolts Z envelope 15mm Pipes, cables