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Insertion Magnets and Beam Heat Loads

Insertion Magnets and Beam Heat Loads. Beam heat loads Magnet design issues related to heat loads. Ranko Ostojic AT/MEL. LHC experimental insertions. pp collisions at 7 TeV generate 900 W at L nom carried by the secondaries to each side of LHC experimental insertion. P/L (W/m).

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Insertion Magnets and Beam Heat Loads

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  1. Insertion Magnets and Beam Heat Loads • Beam heat loads • Magnet design issues related to heat loads Ranko Ostojic AT/MEL

  2. LHC experimental insertions pp collisions at 7 TeV generate 900 W at Lnom carried by the secondaries to each side of LHC experimental insertion. P/L (W/m) Final focus Matching section Separation dipoles Dispersion suppressor

  3. Heat load in the Low-b Triplet External Heat Exchanger Average load: 7 W/m Peak: 14 W/m Total: 205 W T. Peterson, FNAL Technical Note July 2002

  4. Heat load in the Low-b Triplet Peak power density: 0.45 mW/g N. Mokhov et al, LHC Project Report 633

  5. MQXA low-b quadrupole (KEK) Coil ID 70 mm G = 215 T/m at 1.9 K Conductors 1/2 Width 11/11 mm Mid-thick 1.48/1.34 mm Strand dia 0.815/0.735 mm No strands 27/30

  6. MQXA Heat Transfer Experiments (I) Exp Conductor Strand material Cu-Ni Strand dia 0.814 mm No strands 27 Cross-section 1.47 x 11 mm Length 177 mm Insulation Upilex 15 mm/25 mm pitch 50% overlap + Upilex 6 mm/50 mm B-stage epoxy 10 mm pitch 8 mm (2 mm gap) N. Kimura et al, IEEE Trans. Appl. Superconductivity, Vol 9, No 2, (1999) p 1097.

  7. MQXA Heat Transfer Experiments (II)

  8. MQXA Heat Transfer Experiments (III) • Conclusions: • effective channel diameter ~ 35 mm • Conduction important at higher heat flux • AC loss measurements give consistent results • Maximum allowed heat load ~ 18 mW/cm3

  9. MQXB low-b quadrupole (FNAL) Coil ID 70 mm G = 215 T/m at 1.9 K Conductors 1/2 Width 15.4/15.4 mm Mid-thick 1.45/1.14 mm Strand dia 0.808/0.650 mm No strands 37/46

  10. MQXB Heat Transfer Experiments (I) Insulation 1st coil layer Polyimide 9.5 mm/25 mm pitch 55% overlap + Polyimide 9.5 mm/50 mm QXI pitch 11.5 (2 mm gap) 2nd coil layer Polyimide 9.5 mm/25 mm pitch 43% overlap Polyimide 9.5 mm/25 mm QXI pitch 50% overlap L. Chiesa et al, IEEE Trans. Appl. Superconductivity, Vol 11, No 1, (2001) p 1625.

  11. MQXB Heat Transfer Experiments (II) • Conclusions: • AC loss results consistent with assumption of “blocked • cooling channels” • Maximum allowed heat load ~ 1.6 mW/g

  12. MQM matching quadrupole Coil ID 56 mm Gradient 200 T/m at 1.9 K 160 T/m at 4.5 K Conductor Width 8.8 mm Strand dia 0.480 mm No strands 36 Insulation Polyimide 8 mm/25 mm pitch 50% overlap + Polyimide 9 mm/50 mm unc. poly. 6 mm pitch 11 mm (2 mm gap)

  13. MQY wide aperture quadrupole Coil ID 70 mm Gradient 160 T/m at 4.5 K Conductor 1/2 Width 8.3 mm Strand dia 0.48/0.73 mm No strands 34/22 Insulation Polyimide 8 mm/25 mm pitch 50% overlap + Polyimide 9 mm/50 mm unc. poly. 7 mm pitch 11 mm (2 mm gap)

  14. Separation dipoles (BNL) Coil ID 80 mm Field 3.8 T at 4.5 K (2.4 T at 4.5 K in IR1/5) Conductor Width 9.73 mm Strand dia 0.648 mm No strands 30 Insulation Kapton CI 9 mm wide 50 mm thick pitch 50% overlap + Kapton CI 9 mm 50 mm pitch 50% overlap

  15. MQTL Coil ID 56 mm Gradient 120 T/m at 1.9 K 90 T/m at 4.5 K SC wire 0.73 mm x 1.25 mm (with enamel insulation) Coil Insulation epoxy impregnated

  16. Heat transfer in Saturated He Bath Quench Stability Study of J-PARC Magnets Cable and insulation identical to MQXA 20 mJ/cm3 in a 10 ms pulse Y. Iwamoto et al, IEEE Trans. Appl. Superconductivity, Vol 14, No 2, (2004) p 592.

  17. Summary of expected quench limits

  18. Possible experiments on production magnets QH L4 • MQY in B4: • -Use one QH L2-3 for coil • heating • -Magnet protection by • QHL4 • MQM and MQY in SM18: • Use anti-cryostat heaters • to verify operating • margins at 4.5 K QH L2-3

  19. Conclusions • Heat loads associated to pp collisions are considerable in the experimental insertions, in particular in the low-beta triplets. • Thermal properties of the coils of both types of low-beta quadrupoles were experimentally studied, and confirm a safety factor of 3 with respect to expected heat load for nominal luminosity. • MQM and MQY quadrupoles have insulation schemes analogous to the MB. Similar thermal properties could be expected, but have not been experimentally verified. • Magnets operating at 4.5 K are expected to have higher quench limits for transient losses, but lower for continuous losses than at 1.9K.

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