CERN internal review of superconductors and magnet laboratories
CERN, internal review of superconductors and magnet laboratories, 19 th May 2009 LHC OPERATION AND SUPPORT E. Todesco Magnets, Superconductors and Cryostats Group Technology Department, CERN Acknowledgements: A. Siemko, W. Venturini Delsolaro, L. Walckiers, E. Todesco
MAGNETIC MEASUREMENTS AND POWER TEST General strategy: CERN should have the possibility of testing during the whole LHC life any magnet of the machine Magnets that today cannot be tested at CERN: the triplet MQXA and MQXB, and the separation dipoles No equipment for magnetic measurements is available The LHC MQXA made by KEK E. Todesco LHC separation dipole made by BNL 19 h May 2009 – Review superconductors and laboratories - 2
MAGNETIC MEASUREMENTS AND POWER TEST SM 18 has been designed to test a large number of dipoles and quadrupoles during the production (12 test benches) During operation, we do not expect that we need such a high rate, therefore we should rather diversify than focusing on keeping 12 benches, but … remember the 3 -4 incident experience, where testing rate has become critical for operation E. Todesco 19 h May 2009 – Review superconductors and laboratories - 3
SPECIAL NEEDS FOR OPERATION: Fi. DEL Throughout the life of the machine we will probably need to have additional magnetic measurements to have a better understanding of the magnetic model Example: in Tevatron a campaign of measurements was started at the end of the 90 s to improve the knowledge of the magnets, triggered by the RUN II, i. e. , by a substantial machine upgrade The LHC upgrades will probably need more and more magnetic measurements, as new beam physics will point out new directions b 3 decay in Tevatron dipoles, From J. Annala, et al, TD-04 -043 (2004) pg. 38 E. Todesco 19 h May 2009 – Review superconductors and laboratories - 4
SPECIAL NEEDS FOR OPERATION: Fi. DEL Main features of the magnetic model needs Flexibility: being able to measure every type of magnet Speed: being able to measure with high rates (~10 Hz) for decay and snapback Calibration: being able to measure the absolute values of transfer functions (for instance, for the squeeze) – even for correctors (limited knowledge of the TF of correctors can be an issue) Capability of using the LHC control software LSA to steer tracking tests (dipole vs quadrupole, dipole vs correctors) E. Todesco 27 h January 2009 – Fi. De. L 2009 - 5
SPECIAL NEEDS FOR OPERATION: Fi. DEL Proposed program of additional measurements: tracking MB—MCS (b 3 compensation during snapback – already done, but residual b 3 of ~0. 3 units – critical for ramp – more test needed) MQ—MQT (tracking the tune) MQ—MS (Q’ tracking? ) N. Sammut, b 3 correction in tracking test – Fi. De. L meeting, winter 2007 -2008 E. Todesco 19 h May 2009 – Review superconductors and laboratories - 6
SPECIAL NEEDS FOR OPERATION: Fi. DEL Proposed program of additional measurements MQM/MQY transfer functions at low current (beta-beating at injection - done for MQM) MCBX hysteresis: separation, collision, crossing angle (for collision) MQT, MS hysteresis small loops around zero current (tune and chromaticity) W. Venturini Delsolaro – MQM transfer function – Fi. De. L meeting, May 2009 E. Todesco 19 h May 2009 – Review superconductors and laboratories - 7
SPECIAL NEEDS FOR OPERATION: Fi. DEL Proposed program of additional measurements Validation of influence of powering cycles and pre-cycles Any other issue with powering history E. Todesco 19 h May 2009 – Review superconductors and laboratories - 8
SPECIAL NEEDS FOR OPERATION: POWER TESTS AND PROTECTION Proposed program of additional test assistance to the calibration of BLM (energy to quench vs. operating current), dedicated tests with heaters in the magnet cold bore magnet protection, experiment on specific cases with high splice resistance, possibly interconnects on bus-bars with controlled faults, to decide on critical thresholds for operation E. Todesco 19 h May 2009 – Review superconductors and laboratories - 9
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