Assembly of Modules to Cylinders

1
Assembly of Modules to Cylinders

• Georg Viehhauser

2
Assembly at Oxford and KEK

• Barrels come to Oxford/KEK from RAL with all the
  services mounted and tested.
• Modules are only items left to be added at
  Oxford/KEK to complete cylinders
• Limited space ? high precision during mounting
  required.
• Tasks
• Mechanical location fixing of module,
• Thermal mechanical connection to cooling
  system,
• Alignment connection of dogleg.
• After mounting performance has to be verified.
• Use all final (or very close to it) ATLAS SCT
  components (power supplies, off-detector
  electronics, DCS, cooling).
• Compare performance to checks after module
  assembly.
• System studies.
• After passing final acceptance checks Barrels
  are shipped to CERN for final 4-barrel assembly.

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Transport

• Transport from RAL to Oxford/KEK all services,
  but no modules.
• Transport from Oxford/KEK to CERN with modules.
• RAL ? Oxford ? CERN B3, B5, B6, all road.
• RAL ? KEK ? CERN B4, by plane.
• Environment Temperature humidity controlled,
  ESD, mechanically isolated.

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Transport Box

• Two box design
• Inner box
• Al protective frame with conductive plastic
  panels,
• Central part stays around barrels all time (even
  during assembly),
• Wrapped air-tight during transport.
• Outer box
• Steel structure and panels,
• Handling points for shipping.
• Mechanical coupling through wire rope isolators.
• Plane transports might need different setup.

B3 inner box
Box assembly
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Service Cages

• All services, which will later be fanned out on
  the thermal enclosure, have to be stored safely
  for assembly and transport (LMTs, capillaries,
  readout fibres, DCS sensor wires).
• Storage assembly has to
• satisfy ESD and grounding requirements for
  checks,
• provide temporary connections for services during
  assembly checks,
• clear adjacent barrels for 4-barrel assembly.

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Oxford Assembly Area- Heavy Lab
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Module Reception - Storage

• 1500 modules will be shipped from all over the
  world to Oxford
• Shipping box, which
• protects during transport,
• provides safe environment for module checks
  (thermal and electrical connections, so that
  module can be checked without opening),
• has mechanical fiducials to align module for
  module mounting.
• Each module gets tested at Oxford after reception
  (same tests as at module production site).
• Storage in shipping box in humidity statically
  controlled area (up to 400 modules).
• Modules will be kept in shipping box until
  immediately before mounting.

Position fiducials
Module
Connector
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Barrel Reception

• Barrels will be delivered to tent outside of the
  heavy lab.
• After removal of outer box transfer to lifting
  cart.
• Wheel into clean room, lift to cold room floor
  level and move into cold room.
• Remove ends of inner transport box, install cable
  and fibre supports, connect barrel DCS sensors.
• Preassembly checks
• Verify DCS sensor operation.
• Connect cooling system and operate cooling system
  (cold). Verify operation.
• Confirm harness integrity.

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Assembly Overview

1. Mount modules make thermal and electrical
   connections.
2. Verify performance after mounting.
3. After completion of barrel final acceptance test

• Tight schedules require parallel operation of 1.
  and 2. on two assembly stations.
• But switch between them is complex.
• ? Do assembly in groups of 96 modules. First 16
  rows of lower modules (166 96), which then get
  checked. Then mount upper modules and check them
  out.

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Module Mounting

• High 3d-precision during insertion required ?
  robot.
• Additional operations
• Align dogleg to pigtail.
• Apply thermal grease on cooling block.
• Mate pigtail and dogleg connector.
• Mount module cooling block clip.
• Done by hand with tools held by a tooling frame.
• Done row-by-row (first lower, than upper)
• First 1. 2., then module insertion, then 3.
  4.

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Tooling support and alignment

• Tooling frame with vertical and horizontal
  travel, attached to front of transport box.
• Positioning of tools by stages, aligned by hand
  with small lasers.
• Alignment of robot automatically. Survey of
  brackets on barrel with laser sensors.
  Coordinates kept in database for retrieval during
  mounting.

Tooling frame
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Procedure I Align Dogleg
Alignment rods
Template
Connector
Position fiducials

• Remove tab with circuit board from module box
  (module stays covered).
• Transfer pigtail connector position to template
  using position fiducials.
• Position template using alignment rods onto
  barrel.
• Adjust dogleg position (align to module mounting
  bushes) and fix.

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Procedure II Apply Thermal Grease

• A rectangular mask covers cooling block
  (maintains thickness of grease joint).
• Opening of mask just slightly smaller than
  cooling block surface.
• Back of cooling block supported from tool.
• Grease squeezed out of reservoir by piston lever.
• Applicator moves over mask, scrapes off excess
  grease.

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Procedure III Mount Module

• Done by robot (one program)
• Pick up module from box
• Survey module optically verify correct pickup,
  envelope.
• Insert module (robot knows where to put it).
• Drive in screws (limited torque).

Module box
Control by touch-screen
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Procedure IV Apply Clips

• Same tool used for clip removal.

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Procedure V Electrical Connection

• Template aligns connectors on pigtail and
  dogleg.
• Pliers force connectors together.
• Same template also used for disconnecting.

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Clearances

• Exposed wirebonds on modules demand great care.
• All components and module (3-point constrained)
  must satisfy space envelope as given in SCT
  drawings.
• Clearances during insertion 1-2mm on each side
  (depending on barrel).

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Fault recovery

• Care has been taken to isolate robot from
  external faults.
• Separate UPS.
• Compressed air?
• Emergency stop button for operator.
• Recovery software will return the module into box
  after retracing approach path.
• Ongoing task more failure modes will show during
  shake-down before B3 arrival and will be taken
  care of.

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Dismounting Modules

• Reverse procedures of mounting.
• Disconnect electrically.
• Remove cooling block clips.
• Remove module requires splitting of grease
  layer between module and cooling block. Support
  splitting mechanically.
• Return module into module shipping box.

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Time estimates

• Estimated times for assembly
• 5h for 6 modules (1 row of lower or upper
  modules) 45min/module
• 96 modules in 80h 1 week (5d) of 2 daily shifts
  (8h) each.
• ? During established assembly mount modules on
  one barrel for one week, while testing the other,
  then swap.

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Manpower

• Assembly
• 2 ATLAS assembly techs
• Up to 1 tech from electronics workshop
• 2 staff from Oxford, 1 staff from UCL.
• Testing
• 1 postdoc and 1 grad student from Oxford.
• Additional manpower from Oxford and other SCT
  collaborators can be found for limited periods.

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Mechanical QA
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Cooling System

• Evaporative system (cooling capacity ?).
• Drives up to 16 cooling loops (B6 2).
• Two operation modes
• C3F8 about -15 (cold) as in ATLAS.
• C4F10 about 10 (warm).
• Control as in ATLAS
• Mass flows pressure drops adjusted so that
  cooling power exceeds heat load of detector at
  any time.
• Heaters after the detector controlled by simple
  T-feedback so that remaining liquid evaporates.
• No sophisticated control structures, just
  monitoring (? DCS).

Compressor
Storage
Condensor
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Electrical QA

• Repeat measurements as at production sites and
  after reception (allows for direct comparison).

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DCS

• Similar system as in ATLAS
• Sensor readout (all SCT barrel sensors, system
  status and environment) using ELMBs.
• Control and monitoring of power supplies (14
  crates) through ELMB-based crate controllers.
• Distributed PVSS system.
• Hardware interlock of cooling loop temperature
  through IBOXs, interlock matrix and interlock
  card in PS crates.
• Additional interlocks for personal safety.

IBOXs
ELMBs
Environment sensors
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Off-Detector Electronics

• Optical readout (control data).
• One 9U VME crate with VME CPU, up to 14 RODs and
  TIM.
• One ROD reads 48 modules.
• For assembly checks need 4 RODs.
• Only for final acceptance test
• B3 8 RODs
• B5 12 RODs
• B6 14 RODs
• Read out histograms from ROD memory for various
  characterisation checks.

CPU
SCTLV2 PS
REV C Rod
Rev B ROD
TIM
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Power supplies

• Supply HV and LV.
• Crate holds also controller (ELMB-based,
  connected through CAN bus to DCS) and interlock
  card.
• One crate supplies 48 modules.
• Assembly checks need 2(4) crates.
• Final acceptance tests need 8 (B3), 12 (B5) and
  14 (B6) crates.

Interlock card
Controller
LV cards
HV cards
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Power, ESD and Grounding

• Power to critical components (power supplies
  etc.) backed up by UPS.
• Special care has been taken to provide clean
  ground to allow meaningful electrical checks of
  assembled barrels.
• All items in the cold room conductive and
  grounded, standard ESD procedures followed.

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Status I

• Transport infrastructure
• B3 inner transport box complete and at RAL. Outer
  box needs finishing design and construction.
• B3 service cages mechanical parts are ready.
  Mock assembly under way. Electrical components to
  be delivered soon.
• Heavy Lab infrastructure
• Clean room ready, used for power supply tests.
  Ready to receive and store modules.
• Still to be done reception tools (lifting cart
  etc.)
• Cold room service supports being installed.
  After that clean close.
• Power cables ordered. To be delivered in May.
• Readout fibres ordered. To be delivered in May.
• Cooling system Pipework being installed.

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Status II

• Tooling
• Most tools have been built and are being tested
  in the cold room.
• Robot routinely mounting modules. Now
  programming recovery procedures.
• Wait for sector prototype to practise procedures
  in realistic environment.
• Read out and power supplies
• Power supplies 1 crate with cards in Oxford,
  ironing out problems with ELMB crate controller.
• DCS Environment monitoring operating, working on
  power supply control and monitoring.
• Off-detector electronics crate with CPU, TIME
  and 2 RODs in Oxford. Reads out optically one
  module on bench (SCTLV2 power supplies). Standard
  checks working.

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Schedule

• Until arrival of B3 (expect end of June)
• Finish all remaining transport infrastructure.
• Finish all the remaining tasks to build
  infrastructure (cooling system, cables, cold
  room, etc.).
• Test mounting procedures with sector prototype.
  Shake down procedures. Train technicians.
• Get power supplies with control software and
  off-detector electronics with DAQ software
  working.
• Start receiving modules.
• After B3 arrival
• Barrel reception checks.
• Start mounting (production ramps up from 6
  modules /wk to 96 modules/wk)