# Presentation: 194320

## Technology Quadrupole Series (TQ)

*DOE Review of the US LHC Accelerator Project*
*November 2-4, 2005*
- Gian Luca Sabbi

_***BNL - FNAL - LBNL - SLAC***_

## LARP Magnet Program Goals

***FY09 Milestone:***_ _
**       **_**Demonstrate viability of Nb**__**3**__**Sn technology for “Quad-first” option **_

***1. Capability to deliver predictable, reproducible performance:***
**TQ ****	****(Technology Quads, 2005-07)     D = 90 mm, L = 1 m, G****nom**** > 200 T/m**
***2. Capability to scale-up the magnet length:***
**LQ (Long Quadrupoles, 2008-09)     D = 90 mm, L = 4 m, G****nom**** > 200 T/m**
***3. Capability to reach high gradient (pole tip field) in large aperture:***
**HQ (High Gradient Quads, 2008-09) D = 90 mm, L = 1 m, G****nom**** > 250 T/m**

## Technology Quads (TQ)

***Objective: develop the technology base, in preparation for LQ & HQ:***
-  evaluate conductor and cable performance
-  develop and select coil fabrication procedures
-  compare mechanical design concepts and support structures
-  ***demonstrate predictable and reproducible performance***
***Implementation: ***_***two series, same coil design, different structures***_***:***
-  TQC models: collar-based structure
-  TQS models: shell-based structure
***Magnet parameters:***
-  1 m length, 90 mm aperture, 11-13 T coil peak field
-  _Nominal gradient 200 T/m_; maximum gradient 215-265 T/m

## Conductor & Coil for TQC01/S01 Models

- _Strand_:
-  OST-MJR, 0.7 mm diameter
-  Jc = 2 kA/mm2 (12 T, 4.2 K)
-  Is > 1 kA w/optimized HT
- _Cable:_
-  27-strand, 10.05 mm width
-  Mid-thickness: 1.26 mm
-  Keystone angle: 1.0 deg
-  Insulation: S-2 glass sleeve
- _Coil_:
-  double-layer, shell-type
-  one wedge/octant (inner layer)

- MJR strand:
-  same strand for both models
-  70 kg borrowed from FNAL
-  extensive characterization
-  HT studies
-  Cabling studies
-  validation in SQ02 magnet

- Coil cross-section

- Coil end (inner layer)

## TQ Parameters: Gradient and Coil Field

- “MJR” strand
- Jc = 2 kA/mm2
- (12 T, 4.2 K)

- “RRP” strand
- Jc = 3 kA/mm2
- (12 T, 4.2 K)

| Magnet | Top [K] | Gss [T/m] | Bss(body) [T] | Bss(end) [T] | Iss [kA] |
| --- | --- | --- | --- | --- | --- |
| TQS01 | 4.2 | 222 | 11.2 | 11.1 | 12.4 |
|  | 1.9 | 239 | 12.1 | 12.0 | 13.5 |
| TQC01 | 4.2 | 215 | 11.2 | 10.7 | 13.0 |
|  | 1.9 | 233 | 12.1 | 11.6 | 14.1 |

| Magnet | Top [K] | Gss [T/m] | Bss(body) [T] | Bss(end) [T] | Iss [kA] |
| --- | --- | --- | --- | --- | --- |
| TQS | 4.2 | 245 | 12.5 | 12.4 | 13.9 |
|  | 1.9 | 264 | 13.5 | 13.4 | 15.1 |
| TQC | 4.2 | 239 | 12.4 | 11.9 | 14.4 |
|  | 1.9 | 255 | 13.2 | 12.7 | 15.5 |

## TQ vs. IR Quad Design Parameters

## Collar-based Structure (TQC Models)

- _Concept_:
-  Support by thick SS collars
-  Assembly w/external press
- _Advantages_:
-  Proven coil positioning
-  Proven length scale-up
- _R&D issues_:
-  Deliver required pre-stress
-  Max. stress at assembly

## Shell-based Structure (TQS Models)

- _Concept_:
-  Aluminum shell over yoke and pads
-  Assembly based on bladders and keys
- _Advantages_:
-  Can deliver very high pre-stress
-  Large pre-stress increase at cool-down
-  Easily adjustable
- _R&D issues_:
-  Coil alignment accuracy
-  Length scale-up

## Mechanical Design Issues

| Maximum allowed stress in the conductor | TQ, SQ, MAT |
| --- | --- |
| Pre-load strategy for high gradient, minimum training | TQ, SQ |
| Pre-stress at assembly, cool-down and excitation | TQ, SQ |
| End support, axial pre-load requirements | TQ, SQ |
| Pre-stress at assembly, cool-down and excitation | TQ, SQ |
| Trade-offs between stresses in the coil and structure  | TQ, DS |
| Structure alignment and field quality | TQ, SQ, DS |
| Scale-up to long magnets (assembly, systems integration) | LR, DS (LQ) |
| Scale-up to higher field, gradient, aperture  | DS (HQ) |

- The mechanical design optimization involves a _complex set of studies_:

*TQ provides essential contributions, but a combined effort *
*of all LARP Magnet R&D components is required*

## Magnet R&D Plan: TQ Summary

## TQ Model Magnet Goals (1)

_**Phase 1 (TQ baseline):**_** TQS01 & TQC01**
- Develop and verify the coil fabrication technology
- Perform a consistent comparison among mechanical support concepts
*Same conductor/cable and same coil design*
*Same fabrication procedures for all coils*
*Consistent instrumentation and documentation*
- Lay groundwork for Lab collaboration
*Agree on coil module design and fabrication*
*Share fabrication and instrumentation practices*
*Integrate coil fabrication steps *
*Integrate design, fabrication and testing teams** *

## TQ Model Magnet Goals (2)

_**Phase 2 (mechanical & conductor studies):**_** TQS02, TQC02, TQE01**
- TQS02: reconfigure/optimize based on TQS01 results
*Adjust pre-load conditions, assembly sequence *
*If needed, replace one or more coils*
- TQC02: first TQ coils made with “baseline” 54/61 RRP strand
*No changes in the coil/cable design are expected*
*Optimization of mechanical structure w/TQC01 feedback*
- TQE01: disassemble TQC01 coil and test in TQS01 structure
*Compare coil performance in different structures*
*	**(evaluate based on TQS01 and TQC01 results)*
*Explore the feasibility of collared coil disassembly *

## TQ Model Magnet Goals (3)

_**Phase 3 (optimized models):**_** TQS03 and TQC03**
- _Demonstrate the TQ objectives:_
*consistently achieve G>200 T/m after training and thermal cycle *
*evaluate the required design margins (fraction of short sample) *
*characterize the mechanical performance of the two structures*
* *
- _Support the follow-on model magnet R&D:_
- LQ models:
*Provide the *_*optimized coil design*_* for LQ*
*Feedback on *_*coil fabrication methods*_* (integrate with LR)*
*Input for *_*structure selection*_* (integrate with DS)*
* *
- HQ models:
_*Design methods/tools*_* and *_*coil fabrication technology*_* *
*Input for *_*structure selection*_* (integrate with DS)*

## TQ Coil Optimization (TQ03)

**A coil design iteration is planned between TQ01 and TQ03 models: **
***Adjust cable parameters (new conductor etc.)***
***Increase keystone angle (better radial positioning)***
***Optimize cross-section (conductor blocks, wedge) ***
***Adjust the end design (magnetic, mechanical)***
***Modify insulation scheme (reliability, cost, length scale-up)***
**Several factors need to be taken into account:**
***Performance issues and magnet optimization ************ more changes***
***Reproducibility goal and schedule constraints ********* *** less****** changes***
***Length scale-up issues***

## TQ Models: R&D Plan & Schedule 

## TQ Milestones FY05-07

| 12/2005 | Mechanical Design | Compare FE analysis results, evaluate goals
Evaluate results from mechanical models
Assess readiness to assemble/test magnets |
| --- | --- | --- |
| 06/2006 | TQ01 evaluation | Compare test results with expectations
Compare performance of mechanical structures 
Evaluate the conductor performance  |
| 06/2006 | TQ03 readiness |  Review TQ03 goals, plan, schedule
 Assess/confirm coil design iteration results 
 Assess readiness for coil fabrication  |
| 08/2006 | TQ02 evaluation |  Evaluate mechanical design optimization results
 Evaluate the RRP conductor performance
 Feedback for TQS03/TQC03 assembly |
| 05/2007 | TQ03 & TQE01 evaluation |  Assess if stated TQ goals have been achieved
 Conclusions on mechanical design comparison
 Validation of analysis programs & methods 
 Feedback/recommendations for LQ and HQ |

## Conductor for TQ Models

| Model | TQS01 & TQC01 | TQC02 | TQS03 & TQC03 |
| --- | --- | --- | --- |
| Strand type | MJR 54/61 | RRP 54/61 | RRP 54/61 |
| Quantity (Billets) | 70 kg (3) | 40 kg (2) | 80 kg (3) |
| Available (expected) | 4/2005 | 9/05 (11/05) | 03/06 |
| Start of winding | 9/13/05 | 2/22/06 | 7/24/06 |
| Lead time (evaluation) | 5 months | 4 (2) months | 4 months |
| Validation model | SQ02 | SR01 | SQ03 |

- Backup conductor

**TQ02***
**Backup**

**TQ03**
**& LR**
**Backup**

- Strand evaluation & cable fabrication schedule (~2.5 months)

- (*) Additional backup from
- 	HEP/CDP inventory

## TQ01 Progress

-  Finalized cable and coil design; 2D & 3D magnetic analysis completed
-  Fabricated cable for practice coils (HER) and production coils (MJR)
-  Completed coil parts design & procurements (additional parts in order)
-  Completed tooling design & procurement: winding, curing, reaction, potting
-  Completed structure design and procurements (*)
-  Completed mechanical models using dummy coils (*)
-  Completed winding/curing of four practice coils (*)
-  Completed coil winding/curing traveler based on practice coil experience (*)
-  Completed reaction and potting of first pair of practice coils (*)
-  Completed reaction of second pair of practice coils; potting is in progress (*)
-  Mechanical models using practice coils are underway (*)
-  Winding/curing of production coils is underway (*)

*(*) activities performed after June 2005 Review *

## Practice Coil Experience

- _Goals_:	1.  Check/optimize *cable, insulation, end parts, tooling etc.*** **
- 	2.  Check/optimize *fabrication steps*, develop procedures/travelers
- 	3.  Used in mechanical models to provide *input for magnet assembly*
- 	4.  Used to *assess readiness to proceed* with production coils

| Area: | Issue: | Response: |
| --- | --- | --- |
| Parts | Difficult to insert end spacers | Added central cut to increase flexibility |
| Winding | Instances of de-cabling | Modified cable path (reel to coil)  |
| Curing | Cable damage at ramp | Designed/procured modified tooling |
| Reaction | Tin leakage in PC#2 | Cable damage; adjust HT schedule |

- _Issues encountered during practice coil fabrication:_

* **Practice coils are a required step for developing **new, complex Nb**3**Sn coils*
* **Validation goal requires iterations – **increased number** of practice coils to 4*
* **Spare coils** included in TQ model plan provide additional risk mitigation *

## TQ01 Coil Production Strategy

** ****FNAL: Winding and curing of all production coils**** **
** ****LBNL: Reaction and potting of all production coils**
- _Motivations:_
- Practical **limitations on available tooling** (funding profile):
-  winding/curing tooling: 	*only 1 set available*
-  reaction/potting tooling:	*2 sets were procured, but using both at **	**	**	**the same location is more efficient*
- 2) Ensure **uniformity of coil fabrication** for both magnets:
-  LAPAC: “Compare and reconcile” fabrication experiences
-  Structure experiments benefit from identical sets of coils
*As we procure additional tooling and converge on fabrication procedures, we will move towards performing entire coil fabrication at same location*
- Initial feedback regarding _**coil transportation issues**_ is positive

## Coil Transportation Issues

-  The TQ coil fabrication plan relies on capability to safely transport coils
-  Support/protection issues were discussed and fixture was procured
-  Two practice and two production coils were shipped FNAL to LNBL
-  No indications of damage during transport

*Production coils #1 and #2 after transport from FNAL to LBNL*

## TQ Testing Issues & Plans

*Good progress by the Test Integration Group (TIG) on:*
-  Standard interfaces for magnet diagnostics and set up
-  Baseline test procedures (& preliminary TQ run plans)
- Good consistency of magnet instrumentation for TQS/TQC models
- Recent test effort redistributions among labs:
- 06/2005 DOE Review:	All TQ models tested at BNL
- 09/2005 Exec meeting:	TQ are tested at “assembly” Lab (FNAL/LBNL)
- However, each test facility has relative advantages:
-  FNAL: length & sub-cool/1.9K testing
-  LBNL: noise levels, diagnostics
- Need to ensure consistency of magnet testing at different Labs
- Baseline plan may be changed for selected models (w/funding adjustments)

## Summary

-  The TQ series is a key component towards the 2009 milestone
-  Goal: demonstrate reliable operation above 200 T/m
-  Moving forward with first two quads: TQS01 and TQC01* *
* **Converged on **coil design** and **fabrication plan*
* **Integrating **design, fabrication and testing teams*
* **Two practice coils completed**, potting of second pair underway*
* **Three **production coils** have been wound and cured *
* **Mechanical tests using practice coils** are in progress*
-  Future steps:
* **TQS01 and TQC01 tests**: March-May 2006*
* **Further mechanical/conductor tests in 2006-2007*
* **Optimized models** (TQS03 & TQC03) tested in May 2007*