Q0 magnet, cooling, support ideas 1.8K & 4.5K heat extraction Magnet deflections Temperature Margin’s Temperature profile through system Magnet performance for Nb-Ti v Nb3Sn Conclusions What next Other Glyn Kirby

System cross section 150mm Dia pipe 10m long 100Watts 1.9K bath ~ 300 L/min @ 4.5K 100W

Where to put the material Larger magnet apertures Less space for Helium More material in coil support collars Less may hit the magnet. So les heating? Smaller magnet aperture Higher gradient Higher temperature margin’s A little lighter system mass Coil Helium Cooling Helium in inside Helium in outside

Support and Deflection 7m long 1722 Kg 1.1 mm deflection supported at ends 1.1cm deflection with no support

Limits. Quench limits and energy deposition design goals: NbTi IR quads: 1.6 mW/g (12 mJ/cm3) DC (design goal 0.5 mW/g) Nb3Sn IR quads: ~5 mW/g DC (design goal 1.7 mW/g) From : N.Mokohov. For Copper 0.5mW/g = 4.4mW/cm^3 1.6mW/g = 14.3mW/cm^3 Quench limit at Iop/Ic=0.85 and Top=1.9 K -10 mW/cm3 (Nb-Ti ) -36 mW/cm3 (Nb3Sn) Nb3Sn IR quads provide more than factor of 3 larger quench limit with respect to the radiation-induced heat depositions than NbTi

Radiation limits for magnet material 36 mW/cm^3 after 200 Days = 6.8x10^7 Gy Nb-Ti insulation Nb3Sn insulation Max Quench limit for Nb3Sn 10 mW/cm^3 after 200 Days = 1.9x10^6 Gy Max Quench limit for Nb-Ti

Tube from magnet to cold box static LHeII 1.8K 175mm ID, 10M dt 0.1K ,120W 120W with total heat load Cold box 1.8K 1k through insulation at 35W dt 0.1K Coil 2.5K 5.5K Max in coil

Nb-Ti & Nb3Sn quad designs using real cable data. 80% SS @ 1.9K 10.5T max field on Nb3Sn coil 165T/m Nb3Sn Quadrupole

Conclusions 165T/m is possible but not so easy. We need to run at 1.8K 3.5m long Nb3Sn quad need development !! stress management, insulation systems to get the heat out Radiation limitation for Epoxy (Nb3Sn) (or change magnet every 8 months) how to get the heat out of magnet and out of System? finding space for the big pipes that are needed? 1.8K 200mm diameter may be several pipes. Magnet system support needed at several point along 7m’s .

Things to do High radiation load Nb3Sn can get gradient but lifetime is short! If the heat load is limited than magnet will last longer. What are the heat loads? TAS design That are the temperature drop’s through the system with this heat load. What are the coil stresses for a 165T/m 90mm bore Nb3Sn coil. Detailed design for 165 T/m 90mm bore Nb3Sn coil.

We examine a 60 mm aperture Nb3Sn quadrupole using the 16 We examine a 60 mm aperture Nb3Sn quadrupole using the 16.4 mm wide PIT cable developed by University of Twente (non-copper critical current of 2230 A/mm2 at 12 T and 4.5 K). A quadrupole optimised under the same conditions as the Nb-Ti quadrupoles has an operating gradient of 310 T/m with a peak field in the coil of 10.5 T at 20 kA. Conceptual designs of Nb3Sn quadrupoles with apertures in the range of 90 mm were studied by the Fermilab and LBNL teams. We examine a 60 mm aperture Nb3Sn quadrupole using the 16.4 mm wide PIT cable developed by University of Twente (non-copper critical current of 2230 A/mm2 at 12 T and 4.5 K). A quadrupole optimised under the same conditions as the NbTi quadrupoles has an operating gradient of 310 T/m with a peak field in the coil of 10.5 T at 20 kA.

70mm Aperture NbTi 165T/m @ 4. 6KTemp. Margin 1 70mm Aperture NbTi 165T/m @ 4.6KTemp. Margin 1.1K on bore at 80% SS 70mm Aperture NbTi 165T/m @ 1.9KTemp. Margin 3.8K on bore at 80% 70mm Aperture NbSn 165T/m @ 4.6K Temp. Margin 7.4K on bore at less than 80%SS

Detector background field 3.5T to 4T is a problem for 4.5K NbTi at 165 T/m 4T NbTi at 4.5K NbTi @1.9K 1T background field 3.5T background field 1T takes most of the Temperature margin from the NbTi material 13m NO additional external field G.A.Kirby 8th Feb 2007 Q0