Linac 4 FOM Report B Mikulec for the

Linac 4 FOM Report B. Mikulec for the Linac 4 team FOM 01/09/2020 1

Report w 35 – 2 nd Week of Beam Commissioning Monday/Tuesday: • • Adaptive Feed-Forward (AFF) setup by RF team; good results comparable or better to the run last year. Kick response measurements confirm that the 2 quadrupoles in the L 4 T line are inverted. Wednesday: • • • An access for polarity measurements confirmed the quadrupole inversion, which was finally due to an FGC SW problem with the polarity switch (corrected Friday afternoon) Chopper intervention following frequent trips and to solve the issue with delay between kick of 2 plates; a chopper RF amplifier was replaced by its improved spare. Optimisation of LEBT settings by ABP for 3. 1 MV RFQ amplitude (75% transmission through RFQ) Thursday: • • Implementation of simulated response matrix provided by ABP in YASP and kick response measurements identified 2 BPM polarity inversions in the vertical plane --> corrected. Frequent chopper trips. FOM 01/09/2020 2

Report w 35 – 2 nd Week of Beam Commissioning Friday: • • Repair of some loose connection on chopper amplifier 1 N; still several chopper LLRF trips (head monitoring fault perhaps due to dying amplifier; see Monday). ABP LEBT tests for RFQ amplitudes 3. 1 and 3. 2 MV. Profile measurements for 2 different buncher 3 phase settings. Monday w 36: • • • Repair of chopper amplifier 2 N (MOSFET). Punctual source caesiation seems to have worked well (now need to adjust source parameters like gas and frequency) Kick response measurements with updated response matrix and corrected BPM polarity need to follow up some discrepancies in the TL after the PIMS. FOM 01/09/2020 3

AFT FOM 01/09/2020 4

Planning • • Today adjust source parameters after caesiation and take measurements with different RFQ amplitudes to take the final decision on the operational settings; LEBT and MEBT re-optimization by ABP Re-check and potentially optimise optics to Linac 4 dump Stripping foil measurements during this week to qualify new European suppliers for possible future orders From Monday next week beam operation to the LBE dump! FOM 01/09/2020 5