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v3.3.5-pre
Preparation for the HL-LHC Collaboration Meeting
Participants:
Phillippe Belanger (remote), Alessandro Bertarelli, Laurent Ceccone, Ilias Efthymiopoulos, Dobrin Kaltchev (remote), Oliver Kersten, Marco Marchetto (remote), Yannis Papaphilippou, Axel Poyet, Adriana Rossi, Matteo Solfaroli, Guido Sterbin, Markus Zerlauth
Guido set the scene recalling the Run3 wire layout and the need for the Q-feedforward. In particular, he listed three failure scenarios presently under discussion:
overheating of the wire,
fault of the wire power converters,
drift of the power converters and constraints due to the phase interlock.
Adriana presented the status of the first two points while the strategy to attack the third point is still to be discussed with OP and MPP (Machine Protection Panel).
All the wire demonstrators are now in place for Run3 but the wire are not connected with the power converters.
Laurent commented that the hardware part of the WIC is completed but the software side needs still to be finalized.
Oliver asked details about the commissioning. Adriana explained that, part of it, will be done during the HW commissioning:
verify excursions of the 5th axis,
wire thermal imaging in the tunnel during powering test,
test of interlock response,
A second part of the test will be done during the beam commissioning:
check interlock response with the wire.
Guido added that the wires polarity and positioning test will also verify with a pilot at injection. The Q-feedforward will be also tested with pilot at top energy.
Markus pointed out that a series of additional tests may be defined together with MPP for the full commissioning of the wires.
Laurent suggested adding redundancy of the thermal interlock by having two relays in series.
Guido asked Markus and Matteo to comment about the phase interlock needs. They explained that having predefined functions for ramping the wire to a specific current value is not a problem since it can be incorporated in the standard beam process. On the other hand, the possibility to make arbitrary trims during the fill, is not compatible with the standard operational framework. Yannis commented that some flexibility can be compromised to ease the integrability of the wire in the standard operation flow.
Markus stressed that it is very important to define for each wire sub-systems a responsible/expert to be called in case of problem. In fact, once the wire ramp is in the beam process, if the wire hardware is unavailable will prevent the LHC operation. Guido asked if, in this case, degraded mode scenarios can be envisaged. Markus commented that this is not a possible solution.
Alessandro informed that the first test of wire brazing on the ceramic bulk were positive. Full metallography analysis still needs to be done.
In the test is positive the idea is to proceed with the mock-up with 300 mm long insulator (by September w/o contingency).
Marco thanked Alessandro for sharing the drawings of the mock-up and commented on the following point:
fragility of the clamping
fiducialization strategy
feed-troughs cooling
insulation strategy of the wire
biasing (charging) of the insulators due to electrons.
Alessandro took note of the comments explained that there is room for many improvements in the implementation details and that the main focus for the moment was to prove the brazing technology with the reduced wire diameter.
Oliver and Marco commented that a possible collaboration with TRIUMF could aim to address some of those points.
Oliver explained that TRIUMF is in contact with the BCIT (British Columbia Institute of Technology) for interships. There is the possibility to prepare a project description to have a mechanical engineer (experienced professional) to help in scaling-up from the mock-up to a full-fledged design considering for example aspect like integration/survey/cooling/… More specific topic (like impedance) could be left out.
Alessandro asked about the typical duration of the BCIT internship. Oliver explained that they are typical 5-months internship.
We agreed that a new meeting will be held in 10 days.
Actions:
Define the responsible for the wire sub-system for MPP.
Define a date for the wire review.