LPC meeting summary 24-04-2017 - final

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Minutes and Summary

Main purpose of the meeting: DIscussion of the commissioning plan 2017.

Introduction (C.Schwick)

Christoph listed some of the main ongoing activities: 

Commissioning plan 2017 (Jörg Wenninger)

Jörg presented the commissioning plan for this year.

In the commissioning most of the time is now needed by the optics measurements. Jörg stated that now experts should start to think how these activities can be optimised (as it was done in the past for the collimator settings). 

For the VdM scan the same optics as in 2016 will be used (no ATS). Jörg estimated that over-all no significant loss is time will be caused due to this even though some extra validation steps have to be executed at injection. On a question of Witold Jörg confirmed that the optics within the closed bumps should be exactly the same as in 2016. 

New items to commission this year would be the 

Concerning the experiments magnets Jörg said that ATLAS and CMS can decide themselves when they want to switch on or off their magnets. For ALICE and LHCb they can be switched on once the orbit at injection has been defined. The experiments may choose their preferred polarity. LHCb remarked that they are interested in switching their magnet on as late as possible.

Splashes will be delivered during the initial threading, however the dedicated splashes for commissioning in the experiments will be done in a dedicate session a bit later (after the meeting this session was tentatively scheduled to be on Thursday the 4th of May). ATLAS requested a bunch intensity of 1x109 . Jörg remembered that in the past örg remembered that in the past the intensities were a bit higher (2 ~ 3 x 109) but the intensity can be adjusted easily during the splash session. CMS requested the splashes to be in a bucket far away from the about gap (e.g. bucket 1000).

After the first three to five days of commissioning it should be possible to determine the maximal IP shift for CMS. There are then still some days to decide which final value to adopt (approx. until day 10).

CMS expressed interest to have some first fills with Stable Beams before the scrubbing run. Jörg stated that this should be possible to organise.

As last years collisions will be looked for, for the first time with pilot bunches. If collisions cannot be found in an experiment the commissioning programme will be continued and collisions will be then established when the first full intensity bunches will be ramped and squeezed in the machine. At this point it is possible to let the beams collide some hours for experiments to take some commissioning data (or to do some first mini lumi-scans).

ATLAS and CMS both are interested to know the filling schemes for the various commissioning steps and also during the intensity ramp-up in advance.