HQ Status and Plans
G. Sabbi
High Luminosity LHC Annual Meeting
Daresbury, UK, November 11-14, 2013
HL-LHC Annual Meeting, November 2013
HQ Planning – G. Sabbi
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HQ Program Status/Plans
• HQ02: test second-generation HQ coils including
 provisions for coil expansion during reaction
 provisions for improved electrical integrity
 cored cables for suppression of eddy current effects
• HQ03 model using uniform, final design and process
 Realistic field quality & performance reference for HL-LHC
• Detailed discussion of HQ program status and plans took place in July
• The resulting summary document is available at:
https://plone.uslarp.org/MagnetRD/ModelQuadrupoles/HQ/Meetings/2013/
2013-07-30/HQ-plans-2.docx
• In the next slides, we review and update some of the key points
HL-LHC Annual Meeting, November 2013
HQ Planning – G. Sabbi
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HQ02a-2 Test Summary: results vs. plan
• Achieve highest possible current at 2.2 K and 4.5K with current
configuration
• First quench above 15kA: no performance loss after thermal cycle
• Slow training at 2.2K above 15kA, several coils/locations but all in
high field (pole) area
• Clear signs of insufficient pre-load, as expected
• Fall backs at moderate miits, with slow retraining
• No performance loss at 4.5K, achieving 98% of SSL at 4.5K and
enabling detailed performance studies in many areas:
• ramp rate, quench velocities, performance degradation
limits due to stress, high miits etc.
• Perform additional magnetic measurements and heater studies
• Full characterization completed
• Incorporate acoustic sensor and quench antenna for additional information
on quench development -- Completed
• Resolve inductance questions -- Problem tracked to 15kA header
HL-LHC Annual Meeting, November 2013
HQ Planning – G. Sabbi
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HQ02a2 Test Summary: results vs. plan (2)
• Continue quench protection studies, use temperature that allows highest
fraction of SSL – 4.5K
• Establish miits budget (ok if it detrains but we want to go back within 5%
of maximum achieved fraction of SSL)
• Not possible due to slow training and easy detraining, but 98%
SSL allowed to establish no degradation up to 16 miits
• Complete quench integral study and add small (2.5-5 mOhm) dump
resistor
• Completed no dump and 5 m-Ohm, results are close, 2.5 mOhm
must be in between
• No high miits quenches directly aimed at establishing performance
degradation in this test
• Added: studies in preparation for CLIQ test
• More details on AC losses, comparison with HQ01e
HL-LHC Annual Meeting, November 2013
HQ Planning – G. Sabbi
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HQ02b assembly plan
Option 1: perform a complete disassembly of HQ02a
• Attempt to understand and fix faulty strain gauges
• Reassemble with higher pre-load (level to be discussed) and/or coil
configuration changes (update: no coil changes needed)
Option 2: Increase the pre-load
• Currently leaning toward option 2: there is no need to exchange coils, and
strain gauge study could be performed separately
• However, it means no reliable coil stress measurements in HQ02b
• It would also prevent from removing the warm bore guide blocks
 We will have a dedicated meeting in 2-3 weeks to discuss
Future HQ02 assembly should include warm magnetic measurements
• A plan is in place, with FNAL support
• Include correction of high field errors with magnetic shims
• Discuss limitations due to presence of guide blocks in option 2
HL-LHC Annual Meeting, November 2013
HQ Planning – G. Sabbi
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HQ02b Test at CERN
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Perform 1.9K measurements up to maximum achievable current
Establish performance improvements/degradation with higher pre-load
Robustness studies: large number of cycles, full accelerator cycle
Incorporate/characterize new instrumentation (QA, acoustics etc.)
Assess performance of CLIQ system for magnet protection
Establish safe miits budget as was planned for HQ02a-2
Extend quench protection studies within safe miits budget
• Quench integral, heater tests, CLIQ etc.
• Perform study of degradation vs. MIITS (to be discussed)
• Perform magnetic measurements (to be discussed)
Timeline: with simple pre-load increase, magnet could be at CERN in (late)
February; one additional month for full reassembly.
Discussion on planning and organization for HQ02b test is starting: test
plan/priorities, definition of key roles and responsibilities (LARP/CERN)
HL-LHC Annual Meeting, November 2013
HQ Planning – G. Sabbi
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HQ03 Plan
• Coil fabrication is progressing well, expect to have coils ready following the
test of HQ02b at CERN
• However, coil strain gauges are an issue: we need to understand and fix
reason for failures in HQ02 (and LQS03)
• This may require dedicated tests/analysis and may cause delays
• Option 2 assembly for HQ02b means no magnet feedback before HQ03
• Also, we want to implement a QXF-style heater design in coil 26 (spare) and
possibly in coil 25 (last coil of nominal set) – this is also on the critical path
• Planning to implement magnetic shims for correction of high current
harmonics (based on warm magnetic measurements) and magnetic shims for
correction of persistent currents (based on calculations and HQ02
measurements)
• Need to decide on test location (FNAL or CERN)
• Discuss status of VMTF upgrade for full current at 1.9K
• Implement upgrades in the magnetic measurement system (both CERN/
and FNAL)
HL-LHC Annual Meeting, November 2013
HQ Planning – G. Sabbi
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