Notes send by James in email:

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Hi All,

Please find below my notes of the WP2/WP13 meeting this morning, where Dominique presented the latest HL-LHC BGI magnet design.

Slides can be found here:

Main outcomes:

The existing IMHH magnets will be reused as trim magnets (rather than MDX type.) Existing power convertors & cabling will be used for trims.
Harmonics for BGI magnet (0.6T) and trim magnets (0.2T) are, in the opinion of Massimmo Giovannozzi, small and shouldn’t be a problem. Nevertheless, to be absolutely sure, he will supervise a graduate to study this in detail (who starts 1^st August).
In case field corrections are needed as a result of this study, Dominique has the option to add shims to the BGI and Trim magnets. Agreed to meet again when Massimmo has results from the study.
Suggestion to study effect of IMHH magnet on LHC beam orbit, ideally by powering only one of the two magnets in the doublet confirmation. Dominque will investigate with EPC the feasibility of changing the powering scheme during a technical stop.
Dominique will now start the technical design & procurement of a pre-series (prototype) magnet. Lead time for production is 9 months.
Total cost for the pre-series magnet, series magnets, a spare coil, modifications to magnet support & power convertors (recycled) = 300 kCHF ( c.f. at time of 2022 BGV/BGI review 600 kCHF for magnets + 720 kCHF for power convertors = 1320 kCHF. )
Suggestion to contact Lotta Mether to check design for possible electron cloud effects.

Further comment for instrument design (Lauren et al.):

Looks like there will be quite limited room for the installation of the BGI-H in 5R4! ( red circle in Fig.7 below. ) Similarly, I guess the same will be true if we install the HV on the opposite face…

Cheers,

James.