Magnetic Measurements: status report and future challenges

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Magnetic Measurementsstatus report and future
challenges
f

• Hank Glass, Fermilab
• Provocateur talk, Working Group T2 (Magnets)
• Snowmass, July 2001
• with J. DiMarco, P. Schlabach, G. Velev

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Outline

• Brief overview of activities at Fermilab
• Probes harmonics coils, stretched wire
• Magnet projects
• LHC, VLHC Stage-1 and Stage-2, NLC
• Future plans and challenges
• Subgroup tasks

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New/Improved measurement tools

• New test stand for superfluid He tests of LHC
  quads
• New rotating coils with new measurement software
  (object-oriented)
• Single-stretched wire (ssw) for integral strength
  and alignment

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MQXP001 on Stand 4
First full-length prototype of LHC IR triplet
Q2 Two thermal cycles so far, 3rd TC begins mid
July (now) Magnetic measurements and quench
testing done below l point (? 2 K)
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3-segment Harmonics Coilfor LHC IR Quad
Q2P1

• 3.688 m
• 5.948 m
• 8.522 m
• 9.591 m

Q2P1
Q2P1
Q2P1
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Harmonics-comparison of MQXP001 with short models
1.500
1.000
q2p1
0.500
Model magnets
0.000
-0.500
-1.000
a10
b3
b4
b5
a6
a8
a9
b7
a4
b6
b8
b9
a7
b10
a3
a5
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Single Stretched Wire System (SSW)

• Single (100mm) wire stretched between precision
  x-y stages with 1mm accuracy linear encoders.
• Integrator measures flux change caused by wire
  motion - flux change same for /- wire motions
  when wire centered in quadrupole.
• Measurement of true axis (not just average) with
  co- and counter-directional stage motions.
• Stages have laser tracker target fiducial mounts
  referenced to wire.
• Adjustable wire tensioning for removal of effects
  from sag

• Uses include MIQ, LBQ, spool, LHC HGQ, and
  NLC prototype alignment measurements

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SSW schematic for LHC quad
MQXP01
3.6 m
8.6 m
5.5m
17.7 m
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SSW NLC Permanent Magnet Measurements
Stability(also see presentation by Kashikhin)
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Measurements of VLHC Stage-1 magnets

• Arc dipole physical properties (interesting from
  measurement point of view)
• length 65 m
• aperture vertical gap 20 mm
• Gradient 4.7 (arc dipoles), 9.4 (dispersion
  supp.)
• C-magnet design allows probe insertion from side
• Warm testing (100), cold testing (10?)
• Other magnets for Stage-1 present no significant
  measurement challenges

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VLHC Stage-1 dipole measurement concept
Rotating coil positioned by precision
strong-back See VLHC Design Study, Section 5.1.7
for details
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Vertical Magnet Test Facility (VMTF)

• VMTF operating parameters
• Toper 1.8 - 4.5 K
• Ioper 0 - 18.8 kA, upgrade to 30 kA in progress
• Magnet length up to 4 m
• He volume - 800 liters
• tested LHC models (1999-2000)
• High Field (Nb3Sn) model tests
• cos ? magnet, June 2001
• Racetrack coil, July 2001
• 2nd cos ? magnet in Sept.
• 1st common coil magnet in Oct.

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VMTF On-line Operations Display
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Magnetic measurement activities at other
laboratories
Volunteers welcome to give status talks!
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Organizing magnetic measurements subgroup

• Please join!
• Develop subgroup schedule
• Discuss measurement issues for future machines
• Write subgroup report

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Challenges and Issues

• What are the difficulties facing measurements of
• NLC magnets, especially main linac quads with 1
  mm center stability requirement
• VLHC Stage-1 and Stage-2 arc magnets
• Muon collider or neutrino factory magnets Other
  magnets for other machines/detectors
• What are drivers for future improvements in
  magnet measurement technology?