Glyn KirbyMagnet AssemblyTechniques

Overview • History of Accelerator Magnets Assemblies

LHC IR Quadrupoles.

• LHC Hi-Lumi Upgrade Models

• MQXC Nb-Ti model triplet assembly • (back up design)

• Nb3-Sn development history. • MQXF assembly procedure (base line design)

History of Accelerator MagnetsLHC IR Quadrupole

Oxford Inst. used a thin spacer, coil was compressed with an aluminum ring, closed gap at cold no movement. Later converted to a 2-in-1 MQY and is in LHC todayKEK compressed the coil with a Yoke collar and large magnetic keys.Fermi Lab used a collar to support the coil forced with a little help from the yoke.

CERN-Oxford Inst.

(LHC development IR)

Fermi lab USA. (MQXB LHC IR)

KEK JP.(MQXA LHC IR)

3

LHC Upgrade Models

MQXC 120 mm / 120 T/m Nb-Ti MQXF 150 mm / 140 T/m Nb3Sn Force 2.8 X MQXC

Extraction the steady state heatUsing one Heat

Exchanger

Large program to study heat extraction through the magnet coils and structure.

Quench limit for NbTi SF 3 4.3mW/cm^3 ?

2% open yoke

6.6% open collar

6

Magnet Assembly Overview

Vertical assembly 9m magnet will need horizontal assembly

Large movements during compressing coil, insulation and collars 2 to 3 cm on dia.

Full length collaring keys

7

Collaring

Design Collar / Coil Stress

9

Collar Initial value Maximum value the beginning of the relaxation

Finish value

2_3 0.7 Mpa -145.4 MPa -77.3 Mpa -76.7 MPa4_3 -0.2 Mpa -141.8 Mpa -73.1 Mpa -68.8 Mpa

Coil stress measurement during collaring.

10

Collapsible Mandrel Extraction

11

End Flange and Joint Box

End flanges welded to

collaring keys

Multi layer joint box

12

4 – 80mm diameter rods temporary replacement for outer shell

Yoke packing factor too high at 99.6% we need to reduce to 98% for the next magnet .

13

Electrical Checks (very important)

We performed electrical checks at each stage of production

1KV pulse test looking for shorts in the coils.5KV ground insulation tests. Resistance and inductance of coilsInsulation between all circuits.Quench heater firing at full 850V, 80A

Nb3Sn

Nb3Sn development historyTQ vs. LQ vs. HQ vs. QXF

15

TQS1 m long500 mm

2006

LQS3.7 m long500 mm

2009

HQ1 m long

570 mm 2010

QXF~1.5 m

630 mm 2015 (exp.)

Substantial development with this type of structure.

#16

Principles of operation Bladder pressurization

Deform. shape withdispl. scaling = 20

#17

Principles of operation Key insertion and bladder deflation

Deform. shape withdispl. scaling = 20

#18

Principles of operation Cool-down

Deform. shape withdispl. scaling = 20

#19

Principles of operation Excitation

Deform. shape withdispl. scaling = 20

#20

Nb-Ti v Nb3Sn comparisonAssembly, Cool-down, and excitation

Nb3Sn low stress during assembly, pressure increases during cool down Loos pressure during powering

shell

CoilCoil

Nb-Ti High pressure at assembly the gradually looses pressure during cooling and powering

Assembly & Insertion of yoke stacks in shell

Outer yoke segments pre-assembled in packs.

4 Outer yoke segments loaded into Aluminum shell.

21

Assembly of Dummy Coil Pack

• Dummy Pack used to preload outer yoke segments.

• Short blocks screwed together.

22

Insertion of dummy coil pack in shell-yokesub-assembly and bladder operation

23

Assembly of 1.7 m long structure Preparation of alignment pins and bushings

24

Assembly of 1.7 m long structure Joining operation of 2 segments (II)

25

Assembly of 1.7 m long dummy coil pack

26

Assembly of full-length structure3.2 m long coil-pack sub-assembly

27

Loading of full-length structureBladder operation

28

Coil pre-loaded

29

3.4m Magnet Manipulation

30

Summary for Assembly Techniques• For the main IR Quad, needed for the LHC

Hi-Luminosity upgrade, CERN with the help of the US labs, are developing a Nb3Sn magnet, with the bladder & key structure.

• As a backup a high heat extraction Nb-Ti model magnet was successfully tested. The techniques used in this assembly can be applied to the other Nb-Ti magnet that are needed for the upgrade e.g. D1, D2, MQY, and zoo of Correctors.

Thanks to the teams. Many people have worked on the Nb-Ti MQXC. And Nb3Sn bladder & key designs. Hear we see a few. Thanks to you all !

Nb3SnNb-Ti

Special thank you to Paolo Ferracin for providing the the B&K slides

The End