Motivation; to design the most compact SC Quadrupole magnet

1
An application of high Tc Rare Earth-QMG
material to ILC Final Doublet Masayuki
KUMADA, NIRS Mitsuru MORITA, Nippon Steel
Corporation

• Introduction
• Motivation to design the most compact SC
  Quadrupole magnet
• Critical current density of Rare Earth QMG
  (Quench Melt and Growth) material is extremely
  high
• Technology of processing of a coil made of a
  high Tc QMG crystal was developed at Nippon Steel
  corporation
• Model QMG coil was made and tested.
• Preliminary model of a Quadrupole suitable
  for ILC final doublet

2
SINGLE CRYSTAL with of RE-QMG
1cm
3
Comparison of RE- QMG with latest high Tccable
and standard superconducting cable
Latest high Tc
Standard SC cable
New material
Jc (A/mm2)
4
- How to make a QMG coil -

• Strong temperature dependence

Slice cutting
Ag sputtering
wafer
Spiral coil processed
Precise machining
5
How to assemble a QMG magnet
assembling
55mm diameter,7 turns 6 layers
6
A very compact RE-QMG QuadrupoleA simple model
for a final doublet
40mm

QMG coil
-


-
-

-

-

20mm
Coil surface(2.2T)
Median plane
Note median plane is on the 45 degree plane
7
Simple RE-QMG Quadrupole Model(see previous
page) courtsy of Koji Takano(http//www.tomagnet
.com)
Jc500 A/ mm2
Contour plot
Field distribution
Tesla
G120T/m
r
Jc500A/mm2
8
How much is the field gradient?Simple scaling
rule

• B of Toroidal coil
• Bm I/(4pr)
• J 500 A/mm2,r10mm, B4T
• Thick rectangular conductor
• factor 2 smaller.

9
Summary

• Jc of RE-QMG coil could be as high as 5kA/mm2
• Jc greater than any other existing materials.
• Better for winding in an application of small
  curvatures into small coils.
• Can make the most compact quad with required
  gradient with this material
• (could be smaller than the BNL compact SC)
• RE-QMG behaves better under high external
  solenoid field of the detector than standard S-C
  or high Tccable.

10
Acknowledgement

• Thanks to
• K.Takano(Takano Original Magnet Inc.)
• E.Antokhin(JST/BINP)
• F.Kircher(Saclay)
• Y.Iwashita (Kyoto University)
• C.Spencer(SLAC)

11
Comparison of Low temperature and existing high
temperature superconducting material(appendix)pro
vided by F.Kircher(Saclay)