# Presentation: 494593

## HQS Progress Report High Field Nb3Sn Quadrupole Magnet 

- Shlomo Caspi
- LBNL
- Collaboration Meeting – CM11
-  FNAL
-  October  27-28,  2008

## Introduction

- _Collaboration :_
-  BNL –  reaction and potting tooling
-  FNAL – magnetic design, Islands, wedges, “end” spacers
-  LBNL – cable, winding & curing  tooling, mechanical design, magnet assembly.

- _Outline :_
-  Magnetic design
-  Mechanical design
-  Tooling design.

- Magnetics

## Coil cross-section and parameters

*Courtesy of V. Kashikhin*

## Iron saturation & field quality - Roxie

*Courtesy of V. Kashikhin*

## 3D analysis - Tosca

*Courtesy of V. Kashikhin*

## Field, Gradient, Stored-energy - Poisson 

## Short-sample straight section

| 1.9 K / 4.4 K | Layer 1 |  |  | Layer 2 |  |  |
| --- | --- | --- | --- | --- | --- | --- |
| A/mm^2 | 2000 | 2500 | 3000 | 2000 | 2500 | 3000 |
| Imax (kA) | 17.5/15.98 | 18.58/16.95 | 19.45/17.72 | 18.14 | 19.30 | 20.22 |
| Bmax (T) | 13.72/12.59 | 14.52/13.3 | 15.17/13.9 | 13.55 | 14.34 | 14.98 |
| Gmax (T/m) | 197/181 | 208/191 | 219/199 |  |  |  |

## Mechanics

## HQS – Mechanical Shell based Structure

-  570 mm outer diameter

_**Components**_
-  Aluminum bolted collars => alignment
- remains in compression from assembly to operating conditions
-  Iron pads and yoke
-  Iron master key => alignment
-  axial rods => axial preload
-  25 mm aluminum shell => azimuthal preload
-  Coil and collar in compression
-  Cooling area
_**Assembly**_
-  60 mm bladders located outside the key span
-  38 MPa pressure (600 + 50 microns clearance for 220 T/m)
-  Collars, pads and key locations optimize to minimize stress

## HQ – CAD Model

- Gap keys slot

- Bolted collars

- Iron pads

- Bladder location

- Al shell

- Iron master key

- Loading keys slot

- Iron yoke

- Pole key

*Courtesy of D. Cheng*

## Design Concept and Guidelines

- Use modified pads and collars for coil alignment
- Collars for azimuthal alignment (**not for pre-stress**)
- Bolted pads for coils assembly
- Keys, bladders and Aluminum shell during final azimuthal assembly
- Axial rods to control axial forces
- Final pre-stress during cool-down by a shell based Aluminum structure
- Maintain full azimuthal contact between coil-island and island-collar
- Bladder and key locations optimized
- Structure to maintain pre-stress up to expected “short-sample”
- 	but coil pre-stress can be reduced if adjusted to the operating point.

## HQ – Mechanical analysisAzimuthal stress in the coil

|  | Target 
219 T/m |
| --- | --- |
| During bladder operation | -90  MPa |
| With loading key | -82  MPa |
| At 1.9 K |  -177 MPa |
| With Lorentz forces | -177 / 20 MPa |

- => High but acceptable stress  at short sample

*Courtesy of H. Felice*

## Winding-Curing-Reaction-Potting

## HQ – Cable optimization

**Test winding samples**
- Variation of the keystone angle, thickness...
- Up to now, 8 cables evaluated

**Micrographs analyzed for each sample**
-  Edge deformation – strand distortion
-  Deformation of the sub-elements
-  Barrier
-  Size of the facets on the surface of the cable

## HQ – Winding tests

- 114 mm aperture mandrel

- 134 mm aperture mandrel

- EDM part return end

- Rapid Prototype (RP) part lead end

- => 120 mm cross-section: minimum pole width 23.8 mm

## Winding tooling

## Winding layer 1

## Layer 2 spacer

## Curing layer 1

## Winding layer 2

## Curing layer 2

## Reaction tooling

## HQ Schedule (updated 9/18/08)

## Summary

-  We have 90m of cable to wind first practice coil
-  Design of coils, spacers, end-shoes, layer-to-layer transition completed.
-  Shipment of tooling for winding and curing in the next few weeks
-  Reaction and potting tooling in final design stage.
-  3D magnetic design completed.
-  3D analysis of structure and assembly underway.