1. MDI workshop, Jan.5,2005, SLAC An application of high T c 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 T c 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  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 T c 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. MDI workshop, Jan.5,2005, SLAC SINGLE CRYSTAL with of RE-QMG 1cm

3. MDI workshop, Jan.5,2005, SLAC 30K 40K 50K J c (A/mm 2 ) New material Standard SC cable Latest high T c Comparison of RE- QMG with latest high T c cable and standard superconducting cable

4. MDI workshop, Jan.5,2005, SLAC - How to make a QMG coil -  Strong temperature dependence Ag sputtering Precise machining Slice cutting Spiral coil processed wafe r

5. MDI workshop, Jan.5,2005, SLAC How to assemble a QMG magnet ＋ 電流 I I I I I Coil magnet Power supply cryostat QMG current lead 77K 63K Reduced pressure 94mmHg Cooling power ： 35W(longer than 8h) 77K→63K ： 45 minutes assembling 55mm diameter,7 turns 6 layers

6. MDI workshop, Jan.5,2005, SLAC A very compact RE-QMG Quadrupole A simple model for a final doublet 5mm 10mm 5mm QMG coil Median plane Coil surface(2.2T) ２０ｍｍ + － － － － － + + + － － + + + + Note median plane is on the 45 degree plane 4 ０ｍｍ

7. MDI workshop, Jan.5,2005, SLAC Simple RE-QMG Quadrupole Model (see previous page) courtsy of Koji Takano ( http://www.tomagnet.com) http://www.tomagnet.com) Simple RE-QMG Quadrupole Model (see previous page) courtsy of Koji Takano ( http://www.tomagnet.com) http://www.tomagnet.com) Field distribution Contour plot r Tesla G=120T/m Jc=500A/mm2

8. MDI workshop, Jan.5,2005, SLAC How much is the field gradient? Simple scaling rule  B of Toroidal coil:  B=  I/(4  r)  J =500 A/mm 2,r=10mm, B=4T  Thick rectangular conductor:  factor 2 smaller.  B of Toroidal coil:  B=  I/(4  r)  J =500 A/mm 2,r=10mm, B=4T  Thick rectangular conductor:  factor 2 smaller.

9. MDI workshop, Jan.5,2005, SLAC Summary  J c of RE-QMG coil could be as high as 5kA/mm 2  J c 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 T c cable.  J c of RE-QMG coil could be as high as 5kA/mm 2  J c 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 T c cable.

10. MDI workshop, Jan.5,2005, SLAC Acknowledgement  Thanks to:  K.Takano(Takano Original Magnet Inc.)  E.Antokhin(JST/BINP)  F.Kircher(Saclay)  Y.Iwashita (Kyoto University)  C.Spencer(SLAC)  Thanks to:  K.Takano(Takano Original Magnet Inc.)  E.Antokhin(JST/BINP)  F.Kircher(Saclay)  Y.Iwashita (Kyoto University)  C.Spencer(SLAC)

11. MDI workshop, Jan.5,2005, SLAC Comparison of Low temperature and existing high temperature superconducting material(appendix) provided by F.Kircher(Saclay)