1 configuration development for hif final focus superconducting quadrupole array hif final focus...
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Configuration Development for HIF Final Focus
Superconducting Quadrupole Array
HIF Final Focus MeetingJuly 2, 2002
Tom BrownChang Jun
Phil Heitzenroeder
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Interface Issues Thermal
• 4 K magnets must be insulated from 4000 C Flinabe in a few mm of space.
Vacuum• 10-6 target chamber needs to be isolated from 10-9 beam lines.• Debris from target must be kept out of beam lines.
Electromagnetic Loads•Forces between quadrupole magnets must be reacted by strutures between the magnets.•Adequate preload on the magnets must be provided to avoid quenching,
Radiation•Magnets must be shielded for 30 yr. life. •Nuclear heating of the superconducting magnets must be as low as possible.
Alignment•Beam alignment must be maintained within TBD dimensions.
Maintenance & Assembly• Array should be capable of tolerating the loss of a few beam lines (symmetric side to side).•Goal: to be able to replace failed beam lines in <6 mos.•Array assembly must be practical from the field construction point of view.
Utility Feeds
Cryogenic feed lines, power lines, instrumentation lines, Flinabe lines from all of the 104 beam lines must all be accommodated.
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Preliminary Concept
• 52 Beam Lines / side
• Focusing magnets utilize Nb3Sn superconductor.
Target chamber
Focusing magnet
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Vacuum boundary
Chamber / Focusing Magnet Interface Detail
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Support Tube / Vacuum Concept
Vacuum Chamber
Alignment Tubes
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Configuration based on the Shell magnet arrangement.
Support tube and guide
Shell magnet concept
Local detail
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Beam geometry used in model
Target
Final focus quadrupoles
Dipole
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Magnet Assembly
Thermal & Radiation Shielding
Nb3Sn Magnets
Inner vacuum pipe
Magnet preload compression jacket
Exploded View
Ground wall electrical insulation
Quadrupole Details
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Shell configuration –Last Magnet
Last Mag dR(cm) (cm)
John's Z coordinates 33.07531.825
Bp field at Rip, T 4.38Bw field at Riw, T 6.13New coordinates:Z1 Inner edge of mag 600.0Z2 Outer edge of mag 725.0dZ mag length 125.0
Rip Inner radius of bore 17.5 dRpic pipe, insul & cooling 2.0Ris Shielding inner radius 19.5 dRs Shield thickness 5.0Riw Winding inner radius 24.5 dRw Winding build 3.0Row Winding outer radius 27.5
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Last Mag dR Temp Last Mag dR Temp
(cm) (cm) (cm) (cm)
John's Z coordinates 33.075 John's Z coordinates 33.07531.825 31.825
Bp field at Rip, T 4.38 Bp field at Rip, T 4.38Bw field at Riw, T 5.88 Bw field at Riw, T 5.88
New coordinates: New coordinates:Z1 Inner edge of mag 600.0 Z1 Inner edge of mag 600.0
Z2 Outer edge of mag 725.0 Z2 Outer edge of mag 725.0dZ mag length 125.0 dZ mag length 125.0
Bore inner radius 17.5 Bore inner radius 17.5 < 100 C
Pipe and water coolant thk 1.0 Pipe and water coolant thk 1.0Shielding inner radius 18.5 Shielding inner radius 18.5
Shield thickness 5.0 Shield thickness 5.0Winding inner radius 23.5 Winding inner radius 23.5 < 100 C
Structure, insul and LN2 coolant thk 1.0 Microcrystalline reflectors 0.3 Winding build 3.0 Winding str / LHe coolant 0.7 4.2 K
Structure, insul and LN2 coolant 1.0 Winding build 3.0 4.2 KWinding outer radius 28.5 Winding outer radius 27.5
SS304 banding/shielding 2.3 SS304 banding/shielding 2.3 4.2 KBulk shielding 30.8 Microcrystalline reflectors 0.3
Gap to bulk shield 0.5Bulk shielding 30.6 20 C
Jeff Latkowski shield build Proposed alternate build
Last Magnet Build Dimensions
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Magnets Installed in Guide Tubes
The “nose” is the difficult area. There is insufficient space for the guide tubes. The dipoles here will be supported by the vacuum pipes. Bulk shielding is a problem!
Detail
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Lattice space:60 by 60cm
Simplified Configuration
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Force Direction & Magnitude
0.707q/a
0.28q/a0.07q/a
q=2*107
a=0.6m
710*22
== jio IIqπ
μa
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Edge Magnets
– Note uncompensated edge magnets have 10 times the force on them as inner magnets!
– An option suggested by MIT is to provide a set of “edge magnets” surrounding the quadrupoles. Advantages:
• Force on focusing magnets would be reduced and therefore alignment will be easier to maintain.
• Structures between focusing magnets can be greatly reduced in size.
• The “active” focusing magnets will all be the same and will operate at the same current.
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July 2002 [email protected]
1-6IFE: Conductors section at the End stage of compression
One conductor has 1*10cm section.
40cm
20cm
Electromagnetic Analysis of Shell Type Magnet Design
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A1
B3
B2
C2
B1
A3
A2
B4
C1
C3
ZA1
ZA2
ZA3
ZB1
ZB2ZB3
ZC1
ZC2ZC3
July 2002 [email protected]
2-6IFE: Conductors section of first quarter
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July 2002 [email protected]
6-6
IFE: magnetic forces at conductors (ANSYS, current is 1MA) . (see 2-6 for the conductors position with names)
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Conclusion• The design shown is only a “first cut”.
– Basic philosophy of this design is to allow each focusing beam array to be individually removed.– The inner magnet triplets are all contained in a common vacuum chamber, but there are issues.
1. This design locates radiation shielding in the vortex tube region and around the sides of vacuum housing. Is this adequate?
2. There is insufficient space in first focusing magnet region. This area is almost totally occupied by the focusing magnets, leaving no room for the guide tubes or shielding.
3. All magnets must transfer electromagnetic loads through the superconducting thermal insulation. Concepts for doing this need to be developed.
4. Bulk radiation shielding will be located in the vacuum housing. Outgassing may be a problem.
• Maintainability issues need to be more fully understood from the points of view of component activation and personnel access.
• Shell type magnet design is used since this easily allows “compression collars” to surround the coil to inhibit coil motion. The shell design lends itself to the conical array of magnets.
• Initial electromagnetic analyses have been performed for both the “block” and “shell” magnet configurations. – Forces on the outer coils are large, but the addition of “edge coils” can significantly reduce them.