# Presentation: 274055

## B-layer integration with beam-pipe and services 

***	******	******ATLAS B-layer  upgrade***
***	******	******	******             ***E. Anderssen A. Catinaccio

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***

- What we aim to present here:
- The case studies for the B-layer replacement on which to focus (and possible combinations of them)
- The existing boundaries in terms of mechanical design, existing constraints and services
-  Highlight topics and domains to be studied in detail e.g. composite structures, calculations and stability issues related to support on beam pipe, bake-out and thermal insulation, services

## Framework

- The goal of the workshop is to cover:
- An integrated design with beam pipe, supports, structures and modules, cooling, thermal insulation, services layout etc which follows one of the two case studies presented later
-  The assembly and installation sequence, operations and tooling
- Preliminary calculations on structures, stability during bake-out and operation, frequency behavior
- Any portion of the above can be addressed in detail by interested parties e.g.
- Proposed integrating structures (tied with module supports/cooling which is subject of a different section)
- Thermal optimization with beam pipe bake out
- Methods to support beam pipe

*E. Anderssen, A. Catinaccio CERN*

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***

- Two case studies to develop:
- Working on a new insertable assembly B-layer + beam pipe, inside the existing B-layer
- Working on a new B-layer, extracting and replacing the existing one, optimizing new layer(s) at minimum R

## Envelopes case study A

*E. Anderssen, A. Catinaccio CERN*

***Envelopes case study A***

- Beam axis

- beampipe

- R 25

- R 32

- R 45.5

- Existing B-layer envelope

- Realistic upgrade design parameters as of today

- 3 TBC

- Possible upgrade design parameters in the future

- B-LAYER INSULATION

- New B-layer envelope

- Insertion clearance

- 4.5

- 6

- beampipe

- R 17

- R 24

- R 45.5

- Existing B-layer envelope

- B-LAYER INSULATION

- New B-layer envelope

- Insertion clearance

- 4.5

- 14

- 7 TBC

- 3 TBC

- 7 TBC

## Envelopes case study B

*E. Anderssen, A. Catinaccio CERN*

***Envelopes case study B***

- Beam axis

- beampipe

- R 25

- R 32

- R 76

- Existing layer1 envelope

- Realistic upgrade design parameters as of today

- 3 TBC

- Possible upgrade design parameters in the future

- B-LAYER INSULATION

- New B-layer envelope

- Insertion clearance

- 4.5

- 36.5

- beampipe

- R 17

- R 24

- R 76

- B-LAYER INSULATION

- New B-layer envelope

- 44.5

- 7 TBC

- 3 TBC

- 7 TBC

- Fingers

- Existing layer1 envelope

- Insertion clearance

- 4.5

## Comments on Envelopes

-  New beam pipe radius
- Can be tapered down to R25, theoretically to R17 (instead of R29 now) but:
- will require feedback from future Atlas run: see Ray’s talk at: _[http://indico.cern.ch/conferenceDisplay.py?confId=18750](http://indico.cern.ch/conferenceDisplay.py?confId=18750)_
- Current B-layer envelope: R45.5 to R74 = 28.5 mm radially
- Case Study A has a much thinner radial envelope
- Case Study B is closer to current, but perhaps has 2 layers
- Studies which might give more space
- Insulation thickness between BP And B-Layer
- Radial Adjustment of Beampipe

*E. Anderssen, A. Catinaccio CERN*

## Some New Points discussed today

*E. Anderssen, A. Catinaccio CERN*

***Some New Points discussed today***

- Material budget target 2.5 %
- Some additional services are likely to be needed also for case study B .
- The 4.5 mm left for insertion clearance for case B, page 17, although insertion is done on the surface, are needed anyway for a) insertion into Atlas of the independent beam pipe + B-layer and b) for alignment in situ of beam pipe (adjustments required possibly remotely and to be integrated with supports on existing pixel structure)
- Schedule beam pipe: 2 to 3 years for procurement should leave now 1 year to converge on design
- For both case studies: optimization required for insulation layer beam pipe 7 mm with insulation to new B-layer 3 mm, in relation to cooling power B-layer during bake-out (during bake out, beam pipe temperature 220 C, B-layer target -25 C, module non active, target: maintained at T= -6 C)
- For both case studies: the new B-layer structure shall have stiffening function for the reduced beam pipe (ie a 1 mm CFRP shell at R40 would approximately provide the bending stiffness of the missing Be beam pipe part at R29)
- Modules: use even number (existing cooling circuits); we should provide module size envelope (Giovanni)– we expect feedback proposals on ideal size

## Some Common Points

*E. Anderssen, A. Catinaccio CERN*

***Some Common Points***

- Beampipe and B-Layer are tightly integrated and potentially share supports
- Beampipe adjustment limited or non-existent (small clearances)
- Detector alignment to Beam Axis should be good (and known after runs...)
- Service routing along Beam Pipe inside of Disk active area
- Required for insertion with BP if end caps (Disks) not removed
- All out one side, or out both sides TBD by proposal
- Options depend on whether current B-layer is present or removed
- Re-use of recovered B-Layer services places modularity requirement on layout
- Current B-layer services presuppose at most 7 modules per half-stave, i.e per Opto-Board (in fact 13 per pair)
- There are ~24 B-Layer opto-boards per side meaning that max number of modules (for re-use scenario) is limited to ~312
- Similarly, the supply voltages are equally numbered, though with changes to regulator boards or serial powering could power more than we could read out with ‘old’ read-out technology
- Breaking this modularity would require a ‘new’ read-out technology, perhaps with Opto or LVDS readout amplifiers placed elsewhere in the volume or external
- Breaking the modularity, or not replacing the current B-Layer (and recovering its services) requires additional external services, e.g. cooling, read-out, and LV/DCS
- Penetrations for these in the current service chain need to be developed

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***

- Case study A:
- A new B-layer fitting inside the current B-Layer
- It should fit into the following envelope:
- beam pipe OR envelope: theoretical OR24 (17+7), realistic OR32 (25+7)
- existing B-layer inner envelope: IR45.5 mm
- insulation beam pipe to B-layer: 3 mm (TBC)
- insertion clearance (to existing B-layer): 4 to 5 mm
- adjustment beam pipe and B-layer: none or use insertion clearance.
- 	 radial global envelope new B-layer: theoretical 14 mm, realistic 6 mm
- 	also requires additional servicing (old B-layer still serviced)

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***

- Case study A:
- It should be noted that:
- Unrealistic to converge towards theoretical minimum radius beam pipe before few runs at high luminosity in Atlas: end 2008 or later ?!
- An aggressive concept is required to fit into a very tight envelope (current B-layer thickness ~30 mm against a new allowed between 6 and 14 mm  factor 2 to 5 times tighter)
- Flat module segmentation goes against tight envelope: more and narrower modules are required.
- The beam pipe flange OR42.7 has to slide through the IR45.5 of the present B-layer
- In addition to tight design issues for the new B-layer, stability issues ie sag, vibrations, thermal expansions have to be addressed for this case study and integrated into a very limited space

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***

- Case study B:
- replacing existing B-layer
- Guidelines to be developed further to check feasibility:
- Pull out the beam pipe (R clearance to B layer 2.8 mm)
- Access B layer from ends, EC’s in place, bore diameter 190 mm
- Cut existing services B layer
- Hold B-layer, unbolt support ring for B-layer
- Fully remove ring on one side trapping finger
- Remove B-layer
- Insert new B-layer 

## Framework case study B

*E. Anderssen, A. Catinaccio CERN*

***Framework case study B***

- Pull out the beam pipe (R clearance to B layer 2.8 mm)

## Framework case study B

*E. Anderssen, A. Catinaccio CERN*

***Framework case study B***

- Access B layer from ends

## Framework case study B

*E. Anderssen, A. Catinaccio CERN*

***Framework case study B***

- Cut existing services

- Unbolt support ring; Remove ring trapping finger—currently 1mm larger than Disk IR.

## Framework case study B

*E. Anderssen, A. Catinaccio CERN*

***Framework case study B***

- Remove ring trapping finger and extract

- Unbolt support ring;

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***

- Case study B (replacing existing B-layer):
- Insert new B-layer 
- Envelope now 28.5 from existing B-layer – insertion clearance + 6 to 14 mm from Case A optimization
- New B-layer could be double layer, optimized at smaller radius, then possibly shorter (eta 2.5) (shorter, cheaper ?)
- When beam pipe supported independently  support new B-layer on existing fingers (but nb: support ring Re 86 mm with EC disks at Ri 85 mm)
- When B layer supported on beam pipe (most likely scenario for optimization as for scheme next page)  support assembly on EC end plate; solve thermal stability (bake-out), vibration problems (ie structure B-layer reinforcing beam pipe)
-  Need discussion with Eric on insertion clearances for the two cases

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***

- Case study B:
- It should be noted that:
- Requires wholly removal of both BPSS supports
- Removal of current B-Layer gives access to its old service chains

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***

- Link to existing drawings and models to work
- (Eric can you put some ?)
- Input specifications (TBD)
- ...........................

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***

## Framework

*E. Anderssen, A. Catinaccio CERN*

***Framework***