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HL-LHC Annual Meeting, November 2013 HQ Planning – G. Sabbi 1
HQ Status and Plans
G. Sabbi
High Luminosity LHC Annual MeetingDaresbury, UK, November 11-14, 2013
HL-LHC Annual Meeting, November 2013 HQ Planning – G. Sabbi 2
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 3
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 4
• 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
HQ02a2 Test Summary: results vs. plan (2)
HL-LHC Annual Meeting, November 2013 HQ Planning – G. Sabbi 5
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 6
• 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, test could start in 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)
HQ02b Test at CERN
HL-LHC Annual Meeting, November 2013 HQ Planning – G. Sabbi 7
• 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)
HQ03 Plan