By Susana Izquierdo Bermudez (CERN)

The test of the Q2 cold mass containing MQXFB05 has been completed: the quadrupole reached all requirements for HL-LHC operation.

MQXFB05 reached target current at 1.9 K (nominal current corresponding to 7 TeV plus 300 A) and required no retraining to reach nominal current after thermal cycle. No measurable resistive signals were observed up to the tested current.

4.5 K tests and ramp rate tests up to 100 A/s showed that the magnet behaves like the short models and MQXFB03/B04, with no evidence of performance limitation, and a temperature margin larger than 2.6 K for operation.

As with all MQXFB 7.15-metre-long magnets (a total of seven tested so far) there was no performance degradation after thermal cycle. The orbit corrector was powered in individual and combined mode without quench, and all the circuits were powered together (main magnet + corrector) at nominal current during an 8-hour plateau.  In addition, MQXFB05 has been powered at or above nominal current for a total of 147 hours, of which 120 hours were done in six batches of 20 hours continuous operation.

MQXFB05 is the third MQXFB magnet built with the new generation coils, implementing modifications to address the performance limitation observed in the previous units.

Series production of the quadrupoles continues, with the cold mass containing MQXFB06 completed, MQXFB07 cold mass being welded, MQXFB08 being assembled, and the coils of MQXFB09 being manufactured.

Related

News 28 Jun 24 – Fourth consecutive MQXFB magnet to reach the HL-LHC requirements for operation