# Presentation: 863982

## Mechanical and Integration

**Mechanical and Integration**

- HFT CD0
- 25-February 2008, BNL
- Eric Anderssen, LBNL

## Pixel Mechanics Recent Effort

- Contracted _ARES Incorporated _for analysis on cooling, precision mount design and refinement of ladder stability.
- Phone meetings weekly
- First results –
- May need Sub-Ambient Cooling to meet goals set at time of contract—understanding benefit of cold operation not yet understood
- Simplified Precision Mount
- Sector Stability seems adequate
- Moisture adsorption needs further work
- First stage report due by March
- Results of Hygro-Thermo-Structural Stability (and vibration)
- Kinematic mount design and load transfer
- Move toward construction of prototypes to be verified against models
- Some details from ARES analyses presented in Back-up
- Following are some pictures of current design

## HFT Pixel Structure Installed (Concept)

*‘**D-Tubes’ covered by*
*Pixel Services*

*Articulation Pantograph*

*Beam Pipe Supports*

*Articulation Guides*

*Support Rails and Table*
*Also supports External *
*Service ‘Card Cages’*

*‘**ISC’*

## Components Developed with Ares

*Kinematic Mounts*

*Inlet Duct*

*‘**Strong Back’ with Cam-Follower*
*(part of articulation hinge)*

*‘**D’ Tube*

*Load Transfer Mechanisms*

## Follower guided insertion operation

**Follower guided insertion operation**

*Open*

*Closed*

*Clears Beam Pipe over*
*Large Diameter*

*Clearance for *
*Beam Pipe Supports and*
*Kinematic Mounts*

*Final Motion engages*
*Kinematic Mounts*

*Articulation*
*Region*

## Pixel placement concept

**Pixel placement concept**

- Detector assembly slides in on rails—this is a change from previous 3-Bladed Iris design
- Parallelogram hinges support the two detector halves while sliding
- Cam and follower controls the opening of the hinges during insertion and extraction
- Detector support transfers to kinematic dock when positioned at the operating location

*pixel support hinges*

*cam followers and linear cam*

*slide rails*

*sliding carriage*
*Reason for no bottom*
*Beam Pipe support...*

*kinematic dock*

## Engineering Installation

- Requires that all of delivery system, and kinematic mounts are available by then (half if only 2 sectors installed)
- New Beam Pipe, ISC, Articulated rails/D-tube, and Modified East Cone—See later slides for what these are
- Production Electronics and additional sector assemblies can lag

## IST Mechanics Status

- Change to liquid cooling for IST suggested, after difficulties of Air Cooling realized on Pixel cooling efforts
- Affects how modules are laid out on IST stave structures
- Work on ATLAS Tracker Upgrade for Super-LHC in progress at LBNL and BNL for both Pixel and Strip detector local supports
- IST structures can benefit from these developments
- Use directly the technologies and materials developed
- Modify the geometry to suit IST Module Geometry
- IST Strip sensor and its integration with Hybrid and FE chips should be next effort
- Module needs to be optimized for thermal conduction of heat into structure
- Result of this integration will determine geometry of stave-like support
- Excerpts of work on ATLAS Upgrade staves presented in Backup Slides

## Names of Elements

**Names of Elements**

- New West Cone supports FGT, and is in turn supported by East Cone
- East Cone (retrofit), Supports also ISC (Inner Support Cylinder), which provides installation and environmental volumes for Pixels, and directly supports IST

*SSD*

*IST*

*IFC*

*NWC*

*New Cone Structures inside of Inner Field Cage*

*ISC*

*Pixel*

*East Cone*

## Mechanics Integration and Design

- Global integrating structures Overview in relation to FGT
- HFT Shares support with FGT
- SSD addressed, however it is an independent project...
- Internal HFT geometry
- Pixel and IST integration and assembly sequence—includes FGT and SSD: are integrally related (our design must allow)
- Integration Requirements
- Beampipe Integration and Requirements
- Services Integration
- Schedule/Availability of structures tied—need to start planning manpower profile...

## Global Integrating Structures

- FGT requires a new West Cone in ’09, and SSD plans to be in during the ’09 run as well
- New West Cone (NWC) needs to be available by ’09, but Needs East Cone (equivalent) to support it...
- Proposal Following pages...
- NWC + old East Structure must be able to support SSD
- HFT requires a new East Cone, or at least a modified East Cone
- Aim in component definition is to allow for maximum Parallel integration
- All need to be ready for insertion during an opening
- Cannot tolerate much serial integration in Opening schedule...
- Consequently, many structures need to be available simultaneously and early enough to allow prior integration of detectors...
- Need to understand schedule well to plan construction schedules
- ‘Need Dates’, and proximal integration schedules need to be known to target structure availability milestones for production schedule
- More on this throughout...

## Cut Apart Current Cones August 2009

- Cut Carbon Elliptical Beams avoiding  Al Insert
- Old East Cone and most of Beams to be reused to support New West Cone for first FGT run (no Pixels or IST, but allow SSD to be installed
- Old West cone refurbished into New East Cone in Berkeley
- Aim is to make a design compatible for ‘quick’ swap of east structures (bolted)

*Send to Berkeley*

*Keep at Brookhaven*

*Aluminum Bonded*
*Into Carbon*

## Modify East Cone and Install with New West Cylinder

- View as Temporary Fix—Should be ACAP (as cheap as possible)
- Supports end of New West Cone/FGT
- Replicates Old Beam Pipe Interfaces
- Includes SSD if required
- Only for summer ’09 to ’10 (DATES?)
- Wholly Machined/Bonded Solution
- Tooling to locate Buck Plate while bonding is required...
- Should be possible in ~2wk timeframe...
- Need to do this during same opening that FGT is installed
- Components and tooling must be ready beforehand!

*Buck Plate aimed for*
*Easy Swap of replacement*

*Some Tooling Required...*

*~1.5m*

*SSD Mounts*
*Included*

*Old SSD mounts*

*Part of FGT Budget?*

## Replacement Consistent with IST/Pixel Installation

*Should Be*
*Same Length*

*New East Cone with Cylindrical Shell made from Old West Cone*
*Swap in by matching Bolted Interface to New West Cone...*

*Modification*
*Will Take Up*
*Length...*

*Include SSD interface On Shell **(not shown...)*

*Shell to replace Beams*

## Layout of Insertable Cone Structures in IFC

**Layout of Insertable Cone Structures in IFC**

- Note that SSD and FGT will likely be installed before internal system (IST/PXL) is available
- If SSD not installed could pre-integrate on outside of New East Cone prior to opening...
- Aim is for quick integration of these during any one opening
- As much pre-integration as possible prior to opening is a priority
- ISC with Beam Pipe and IST are inserted first into Cone Structure (with FGT and SSD installed)
- ISC needs to be removed to install IST if it lags pixels

*Gap for ISC services Required thru ISC support off of NCS*

*SSD*

*IST*

*-15C(?)*

*Room Temp*

*Pixels Cartooned in*

## ISC Integrated with IST and Beam Pipe

- Smaller cylinder has both IST and Beam pipe supports Integrated
- Integrate IST first on Small Cylinder where appropriate (MIT or BNL)
- Insert Beampipe and fix on mounts
- Requires long bench to support Beam Pipe until full load transfer to ISC
- Right hand side eventually cantilevered by this structure for insertion into Cone Structure
- Add large cylinder, transfer Beampipe to top support
- no permanent bottom support—interferes with Pixel insertion rails/tooling)
- Dress IST Services on outside of large Cylinder

*Separate Cylinders (bolted Interface)*

*Asymmetric Beampipe Allows for Articulation of Pixels to small Radius prior to insertion into smaller cylinder*

*Double support provides moment constraint for insertion*

*Include Service Penetration/Seal*

*Insertion Rails*

## Assembly Sequence Aims at Parallel Integration

**Assembly Sequence Aims at Parallel Integration**

*PXL*

*PXL Insertion (after Cone in STAR)*

*FGT*

*SSD*

*SSD*

*NCS*

*SSD *
*Integration*

*FGT  Integration*
*(COMPLETED PRIOR)*

*PXL IS Insertion*
*(includes BP and IST)*

*Insertion into STAR*

*SSD Integration *
*Done independently*
*(as required)*

*’**09-10**?*

*Intention to place PXL engineering ‘patch’ system as early as possible—preceding  IST Installation*

*IST/ISC follows FGT by ~1yr*

*Pixel Compatible BP ‘should’ be ready...*

## Design Requirements and Interfaces

- Previous slides showed only how we intend to assemble the detector in a ‘Big Picture’ sense...
- Important to define this ‘Top Down’ as this more clearly defines need dates for individual structures...
- Assembly sequence also defines what is supported where and by what component(s)
- Top Down approach makes support chains clear
- Presents a clear inroad to define structural requirements of each deliverable in a tiered fashion
- In defining these, we must also apply auxiliary constraints, e.g. service volumes/routing, and Environmental requirements
- Distinct non-interpenetrating volumes must be defined (what can be shared, and what cannot)
- Cross-Sections, gaps, and penetrations must be imposed (and enforced) for servicing various detectors
- Auxiliary constraints will impose additional requirements on structures
- All usually detract from Ideal Performance, so best to identify early

## Beam Pipe Interfaces

- Beam Pipe is integrated structurally with ISC (note IST also installed prior to insertion in Cone Structure)
- Integrated bake-out jackets required in FGT volume (no space for insertable jackets)—propose to replicate on East Side
- See ATLAS Beampipe as example of integrated Bake Out heaters
- Removable bake-out jacket installed in place of Pixels during bake
- Pixels can’t take bake-out temperatures
- Trim heaters are a separate circuit of integrated bake-out jacket—used during operation to prevent condensation on Beam Pipe

*Moment Supports*

*Removable Bake-Out Jacket*

*Integrated Bake-Out Jackets*

*External Support to IFC*
*Far side of FGT (or to *
*West Cone)*

*Trim Heater (and Bake-Out)*

*Supports to ISC*
*(Bottom after Pixel Install)*

*-15C inside of ISC*

## Service Cross-Sections and Patch Panels

- Services Span Environmental Volumes
- Propose to make all penetrations of these volumes with Bulkhead connections
- Sealing to cables, tubes, makes all services one non-modular unit upon sealing
- May interfere with assembly sequences or maintenance
- Service Density of HFT Pixels and IST are low, ATLAS Pixels has ~10X the services in the same radius
- HFT can likely use only the end plate area to make all penetrations...

## Status of Structural Design efforts

- Global Structures like the Cones and ISC are primarily at the layout level
- No detailed models or analysis, only sizing and envelope CAD models exist
- Need to engage Beam Pipe engineer
- IST undergoing changes to layout and cooling scheme
- Design direction exists, working on module layouts
- Pixels most advanced
- CAD models of sufficient detail for FE Analysis exist and exercised
- Several iterations of analysis complete, sufficient to verify design direction and identify prototype effort
- Detailed work on mechanical requirements and interfaces ongoing for global structures

## Tiered Mechanical Requirements

- Maximize Block Elements that need to be aligned (tracks) with 6DOF
- Minimize changes (within cost limits) between surveyed and installed detector elemenst
- Target each tolerance limit locally, and tie to detector resolution
- Pixel internal tied to 20 pixel to pixel ‘Box Tolerance’, e.g. 6 RMS X 121⁄2
- Pixel to IST location tied to IST (or SSD), whatever is tighter
- Geometric requirements are aimed at knowing Detector positions after a survey
- Fabrication tolerances are dominated by mechanical interference and guaranteed overlap not resolution
- Resolution drives stability requirements within and between detectors
- Above paradigm used to attribute stability and tolerance budgets across Local and Global structures—all tied to physics performance
- Operating Stability will be the driving requirement, but includes also any change from survey geometry prior to installation
- Vibration environment measured, method in backup slides to bound problem
- Hygro-thermal deflections yield well to analysis and can be predicted from prototype/FEA iteration
- Cooling and Operational temperature fold into above—represent gradients, and impose isolation requirements on Global Structures

## BACKUP SLIDES

- ATLAS UPGRADE details
- ARES Calculations on Pixel

## Modify Old West Cone at LBNL

**Modify Old West Cone at LBNL**

- Cut off embedded Aluminum inserts and add Flange
- Cut-Length optimized for ISC and Cylinder that will replace current Beams...
- Will Become new East Cone—aim for quick swap of temp structure

*Trim*

*Bolt*
*Flange*

## Flange on New East Cone (Detail)

- Auxiliary Goal of Flange Two-Fold
- New Interface to West Cone (remove old BP Interface Plate and beams)
- Use Same Tool for large cylinder of IST and Intra-Cone Cylinder (SSD Support Shell)
- Need to understand if this effort is cheaper than using tooling for NWC (available as NWC extant for FGT installation)
- However—this represents current ‘baseline’

*Gap or Standoffs for *
*IST Services Needed*

*R220-225*

*ISC*

*Bolt PCD same as ‘Buck-Plate’*

## Single DOF SHO used as model

- Frequency can be approximated from peak gravity sag of FEA models (under-predicts for most structures)
- Other approximations can be extrapolated, using root(k/m)
- RMS is a strong function of the first fundamental frequency
- Q is fixed based on material
- Typical Q for CFRP is ~10, i.e. 5% damping factor (need to measure)
- Effective Q increases for increasing modes (more material involved in deflection)—f1 dominates
- PSD (Power Spectral Density) in units of g2/Hz is known for STAR
- g2/Hz ~power/cycle/unit-mass, can use to tie to various phenomena, e.g. air-flows
- Useful tool to direct optimization
- Thanks to Bill Miller for introducing this method

*m*

*mg*

**

***

***

** Least offensive clip art for ‘Spring’*

*mg=k**** subbed into frequency eq.*

## Stiffness Criterion

*6m RMS Requirement*

*Heavy MFG PSD**
*1 X 10**-6** g**2**/Hz*

*Light MFG PSD**
*1 X 10**-7** g**2**/Hz*

*Frequency*

*Target *
*Frequency*
*Range*

** Source: Newport Optical Table design appendix*

## Methodology

- SDOF SHO is typically less stiff than a real structure, i.e. a real structure with given gravity sag has higher F0 than this model predicts
- Adds conservatism
- PSD for STAR is not broadband, so using previous figure to set requirements is conservative
- Final design would use exact PSD
- Heuristic approximation of allowed gravity sag gives quick direction to improve designs—particularly for global supports
- Assuming rotationally symmetric geometry, also bounds lateral modes
- Higher order modes typically unimportant, though useful to verify accuracy of models when correlating with measurements of real structures (prototypes)

## IST versus ATU—differing goals

- ATU has different thermal requirements
- For ATU, sensor temperature is more important than FE temperature (radiation damage is higher)
- Energy density is much higher for ATU and the coolant temperature much lower (-35C or lower)
- Strip prototype thermal image shows that thermal path to FE chips for a strip sensor is important
- Despite requirement differences, the Stave structure performs similar enough tasks
- Stable support which rejects influence of distorting forces
- A cold surface which extracts heat from modules
- Modular building approach
- Thermal and structural approaches are similar, and IST requirements are less challenging
- IST needs to optimize Module to meet thermal goals, and integration techniques

## ATU Pixel Stave Prototype - III

**ATU Pixel Stave Prototype - III**

- Final assembly(foam+fiber halves glued together around tube)
- Heaters on YSH-70 side _only_ for first measurements
- Platinum-on-silicon heater in middle to simulate pixel module and copper-kapton heaters on either side to minimize end effects.
- Silicon heater represents accurately the Heat load of a sensor allowing direct IR measurement of temperature

*6.9 mm*

*24 mm*

*Foam*

*260mg/cm**2*
***(exc. Pipe)***

*=> 130mg/cm**2 **for *

## ATU (SLHC) Pixel Stave Prototype - I

**ATU (SLHC) Pixel Stave Prototype - I**

*Tube with CGL7018*

*YSH-70 and K13D2U glued to foam*

*Tube in foam with CGL7018*

## ATLAS Pixel Stave Prototype Development

**ATLAS Pixel Stave Prototype Development**

- Thermally conducting foam obtained from Allcomp, Inc
- 0.18 g/cc as delivered
- Thermal conductivity not measured (yet)
- Small prototype (20 cm long and about 2.4 cm wide) made – see photos previous page
- Small aluminum tube(2.9mm OD and 2.3mm ID) used to simulate about what might be used for CO2 at SLHC
_**__*needs to be optimized for IST Flow requirements*_
- Foam machined (easy) to shape and with groove for tube
- CGL7018 used to couple tube to foam
- Hysol 9396 loaded with Boron Nitride (30% by weight) used to couple facings to foam
- One facing is YSH70 cloth, 140 microns thick
- Second facing is K13D2U 4-ly laminate 300 microns thick (90-0-0-90 orientation)
- Estimate of %X0 for IST ~0.75% X0 with coolant (structure only)

## Thermal Performance

**Thermal Performance**

- IR camera used
- Water coolant at 1.0 l/min at 20C.
- Vary power level in silicon heater
- And separately in copper-kapton heaters to about match Power/Area

*Label**	**Emis**	**BG**	**Ave**	**SD**	**Max**	**Min**	**Unit*
*A1**	**0.95**	**19.0**	**27.41**	**0.65**	**28.4**	**25.9**	**C*
*A2**	**0.95**	**19.0**	**27.36**	**0.80**	**28.4**	**23.8**	**C*

*T in boxes*

## Preliminary Thermal Performance

**Preliminary Thermal Performance**

*IST has a target dissipation of*
*0.065W/cm**2*

*FE-I4 goal*

*FE-I3 normal*

*Max. spec*

***

***

** **Includes sensors & power conv. But not cables.*

*IST Goal*

## ATU Nominal Design – Short Strips

**ATU Nominal Design – Short Strips**

*Bus cable*

*Hybrids*

*Coolant tube structure*

*Carbon honeycomb or foam*

*Carbon fiber*
*facing*

*Readout IC’s*

*10cm detectors, each with 4 rows of chips on hybrids*

*Hybrids glued to detectors and this assembly glued to mechanical/cooling support*

*~ 1 meter*

*Note that the Pixel design has a different heat path than a Strip Module—the following is more representative of the IST (except this is double sided)*

*ATU Super-Staves are double sided—sensors on each side...*

## Wider Prototype for Strips, goal now ~4cm

**Wider Prototype for Strips, goal now ~4cm**

*1m prototype*

*2.8mm tube/foam*

*4.9 mm tube/foam*

*Flattened tube*

*Note prototype width is about 7cm – set in 2006*

*POCO foam: about 0.5 g/cc thermally conducting carbon foam*

*Facings are K13D2U fiber laminates*

*Carbon honeycomb*

*All tubes aluminum*

## Thermal Prototypes—Strips with Hybrids

**Thermal Prototypes—Strips with Hybrids**

*Water at about *
*20C*
*IR images*
*Before and*
*after thermal *
*cycling between*
*20C and -35C*
*50 times*

*3.3 W/hybrid(0.55 W/chip) *

*No Power*

## Sector/ladder design—what was analyzed

**Sector/ladder design—what was analyzed**

*thinned MAPS chips*
*2 cm by 2 cm, 50 **μm thick*

*multilayer aluminum kapton*
*flex circuit cable for signal and power*

*thin carbon composite substrate*

*carbon composite support beam*

*Heat loads defined by region on MAPS chips and End of Ladder electronics*

*Ladder Overhang important*

## Fins versus Ducted flow (improved Heat Transfer)

**Fins versus Ducted flow (improved Heat Transfer)**

## Results from above—Fins Win

**Results from above—Fins Win**

## Internal Fins base lined for further Analysis

- Flow rates of 4-8m/s used—produces flow in the 50CFM range, which seems reasonable
- Fins required to improve heat transfer area, given Heat Transfer coefficients for air of this velocity
- Fins also improve some of the structural deformation modes, but add material
- Don’t know how to build fins yet
- Have not modeled air flow, so cooling rates likely optimistic
- Fin size and position likely needs further optimization
- Need to build prototypes to guide this

## For flow on inside only, most recent result

## Displacement from imposed Thermal Distribution

*No Silicon*

## Load Transfer from insertion table to Mounts

## Hinge analysis—Mount Engagement Forces

- 15kgf (~150N) applied at end of magenta links (rigid elements)
- Stresses are low (from an alternate analysis not shown)
- Deflections are shown on Y axis only (note reversal)
- Max Deflection is 0.14mm (negative Y)
- Aim is to show that Hinge, under insertion load will hold kinematic mounts within appropriate acceptance window of Kinematic Mounts
- Analysis shows this is currently acceptable

*-0.14mm*

*+0.015mm*

*+Y*

*Analysis of initial hinged parallelogram concept; additional concepts are also being investigated to understand if an even simpler solution is available.*
*Analysis shows that this is viable*

*~0mm*

## Pixel D-Tube to ISC mounts

## Pre-loaded mount and Registration