Participants: Simon Albright, Fanouria Antoniou, Hannes Bartosik, Jan Borburgh, Louis De Mallac, Gian Piero Di Giovanni, Eve Fortescue-Beck, Georgi Minchev Georgiev, Matthias Haase, Serge Pittet, Andrea Santamaria Garcia, Jocelyn Tan.
Approval of minutes
The minutes of the LIU-PSB WG #211 meeting were approved.
Communications
- An LIU Beam Performance Meeting was held. The outcome of the CSR 2018 was discussed, as well as the longitudinal limitations for LIU-PS related to the RF upgrades and mitigation strategy.
- The EVM baseline for the PSB is now active.
Follow-up of open actions
I. Lamas (2018-04-03): Prepare the ECR for the PSB scraper/absorber describing both the dismantling of the current equipment and the installation of the new one.
- The ECR will be finished this week.
Qstrips specifications with respect to beam dynamics (F. Antoniou)
- The injection energy to the PSB will be increased from 50 MeV to 160 MeV with the connection to Linac4. There will be a new H- charge exchange injection scheme.
- The ramping down of the magnets will induce eddy currents. This will generate multipolar components, perturbing the optics of the H- injection scheme and causing beta-beating, mostly in the vertical plane.
- Simulations show that this beta-beating induces 15-20% of losses.
- To mitigate the beta-beating a correction using QDE3 and QDE14 has been proposed in the past and was recently revisited.
- The optimal values of k3 and k14 were computed to minimize the beta-beating along the lattice for different working points. This was done at a cycle time of 1 ms, where the perturbation is maximal.
- The vertical beta-beating was corrected from about 20% to about few % and the tools are ready to be used for any working point.
Comments
- H. Bartosik asked if it is possible to locally reduce even further the beta-beating at the extremes by selecting another pair of quadrupoles, such as the 1 and 15. F. Antoniou commented that the set of quadrupoles 3 and 14 seemed to be the best option, but that she will re-check the simulations.
LIU PSB Q-strip power converters (L. De Mallac)
- The first functional specification of the Q-strips did not take into account the increase of current associated with an extraction energy of 2 GeV, so a new study was needed to take into account the new constraints for the power converters.
- New calculations of the functions for beta-beating correction and tune re-matching have been performed by F. Antoniou (see previous presentation).
- One of the proposal is also to update the MPS waveform adding a 50 ms flat bottom before injection for the stabilisation of the magnetic field. The Q-strip converters will ramp-up during this flat bottom
- The foreseen converter type (CANCUN 100) can handle the updated current waveforms. One has already been installed for testing and the rest will be installed during LS2.
Comments
- G. P. Di Giovanni commented that before the testing of the power converter this year some work needs to be done at the LSA database level.
- G. P. Di Giovanni commented that the specification is currently being written and a meeting will be held next week for approval.
AOB
Tour de table
- S. Albright reported that the reliability run for the phase noise blow-up is ongoing, and that the LHC25 and BCMS beam types have been set-up.
- M. Haase reported that the planning for the RF in ongoing and that they will meet with D. Hay to review the schedule.
- G. P. Di Giovanni reported on behalf of J. Coupard that today and tomorrow they will be an integration meeting for PSB/PS, a PLI meeting, and a dedicated meeting with RF.
Next LIU-PSB meeting: 17th of April 2018 on the LN4-to-PSB connection project by Aurelio Berjillos Barranco.
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