Global support structures

2

Overall support hierarchy

• Inner tracker within one TE (thermal, humidity and Faraday cage), integrated on surface

• OC supported on 4 pts• Strip ECs and pixels supported on rails (4pt)• Barrel strip connection to OC to be defined (likely fixed around perimeter)• 2 pixel support tubes (gas barrier)

– Outer pixel support tube could be the inside of barrel and EC strip structure• Pixel structure and or PSTs will provide overall axial stiffness

3

Outer cylinder (OC) and TE• Present concept is 30mm thick sandwich (T300

+ Nomex core)– Based on CMS tracker support tube design– Not optimized for space/material

• This also contains the central inner polymoderator

• TE (heater+insulator) in panels on inside of OC– In barrel section also inner cooling layer

• Cylinder stiffness from structural bulkheads– Access to inside of tracker requires external hoop

4

(Tentative) outer envelopes

• Still need to see what we can achieve

Central barrel region Outer barrel region Endcap region

z = 0 to 800 z = 800 to 1280 z = 1300 to 3500

LAr cryostat 1153

LAr cryostat shape 1153 to 1150

Cable trays (includes outer polymoderator)

1150 to 1123

Cable tray shape 1123 to 1121

Insertion clearance for OC 1121 to 1101

Outer Cylinder 1101 to 1066

Outer Cylinder shape 1066 to 1061

Thermal barrier 1061 to 1048 1061 to 1051

Thermal barrier shape 1048 to 1047 1051 to 1050

Inner polymoderator 1047 to 1022

Inner polymoderator shape 1022 to 1020

Layer 5 insertion clearance 1020 to 1018 1047 to 1045

Layer 5 outer edge to center of active layer

1018 to 1000 1045 to 1000

Barrel service modules 1050 to 1023

Barrel service shape 1023 to 1020

EC insertion clearance 1020 to 1000

EC outer structure and services 1000 to 980

EC outer radius of active disk and outer structure 980 to 970

Envelope

Corner of last sensor (stereo layer) 1277

End of stave core 1278

Service gap Xxx to 1388

EC insertion clearance 1388 to 1408

EC protective skin and structure 1408 to 1416

Disk envelope outer edge to center of active layer 1416 to 1468

5

Barrel strips• Structure based on cylinders

– Sandwich (as SCT), or– Single skin with stiffening rings– To some extent driven by decision on stave mount system

• Interlinks– Discrete (~8) interlinks (as SCT), or– Continuous (1 per stave)

• Have not gone beyond concepts (design and FEA)

6

Endcap strips• 2 concepts have been studied for 5-disk layout

– Disk based (staggered petals), and– Space-frame (fan)

• Implications of 7-disk layout not yet studied

7

Pixels• 2 packages in 2 support tubes

– Inner two barrel layers• Clam-shell• Either split at z=0 or services to one end

– Outer two barrel layers + disks• Probably separate packages during integration

• Outer support tube could be inner surface of strip structures• Support tubes need to be hermetic (not necessarily structurally)• Crude envelopes have been assigned

8

Summary

• We do have conceptual ideas for all our structures

• There is insufficient effort to drive these concepts to a more mature stage