Glyn Kirby Magnet 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 Magnets LHC 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 today KEK 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. KEK JP. (MQXA LHC IR) Fermi lab USA. (MQXB LHC IR) CERN-Oxford Inst. (LHC development IR)

MQXF 150 mm / 140 T/m Nb3Sn Force 2.8 X MQXC 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 heat Using one Heat Exchanger Quench limit for NbTi SF 3 4.3mW/cm^3 ? 6.6% open collar 2% open yoke Large program to study heat extraction through the magnet coils and structure.

Magnet Assembly Overview Large movements during compressing coil, insulation and collars 2 to 3 cm on dia. Vertical assembly 9m magnet will need horizontal assembly Full length collaring keys

Collaring

Design Collar / Coil Stress

Coil stress measurement during collaring. Initial value Maximum value the beginning of the relaxation Finish value 2_3 0.7 Mpa -145.4 MPa -77.3 Mpa -76.7 MPa 4_3 -0.2 Mpa -141.8 Mpa -73.1 Mpa -68.8 Mpa

Collapsible Mandrel Extraction

End Flange and Joint Box End flanges welded to collaring keys Multi layer joint box

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 .

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 coils Insulation between all circuits. Quench heater firing at full 850V, 80A

Nb3Sn

Nb3Sn development history TQ vs. LQ vs. HQ vs. QXF TQS 1 m long 500 mm  2006 LQS 3.7 m long 500 mm  2009 HQ 1 m long 570 mm  2010 QXF ~1.5 m 630 mm  2015 (exp.) Substantial development with this type of structure.

Principles of operation Bladder pressurization Deform. shape with displ. scaling = 20

Principles of operation Key insertion and bladder deflation Deform. shape with displ. scaling = 20

Principles of operation Cool-down Deform. shape with displ. scaling = 20

Principles of operation Excitation Deform. shape with displ. scaling = 20

Nb-Ti v Nb3Sn comparison Assembly, Cool-down, and excitation Nb-Ti High pressure at assembly the gradually looses pressure during cooling and powering shell Nb3Sn low stress during assembly, pressure increases during cool down Loos pressure during powering Coil Coil

Assembly & Insertion of yoke stacks in shell Outer yoke segments pre-assembled in packs. 4 Outer yoke segments loaded into Aluminum shell.

Assembly of Dummy Coil Pack Dummy Pack used to preload outer yoke segments. Short blocks screwed together.

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

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

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

Assembly of 1.7 m long dummy coil pack

Assembly of full-length structure 3.2 m long coil-pack sub-assembly

Loading of full-length structure Bladder operation

Coil pre-loaded

3.4m Magnet Manipulation

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 ! Special thank you to Paolo Ferracin for providing the the B&K slides Nb-Ti Nb3Sn

The End