Minutes of the 1st WP2 Task Leader Meeting (02.03.2011)
Present: O. Bruning, S. Fartoukh (chair), M. Giovannozzi, B. Holzer, E. Metral
Excused: L. Rossi, A. Wolski
Introduction
The meeting started with an introductory presentation by S. Fartoukh, discussing the baseline beam
and optics parameters for HL-LHC, and in particular beta*=15 cm. The corresponding collision optics
heavily relies on the ATS scheme, which however introduces a series of possible limitations. In this
respect, seven specific tasks were identified (see slides), to be tackled within the next few months in
order to decide whether the ATS can be kept or not as baseline for the HL-LHC collision optics. On
the other hand, based on a quick risk analysis, everybody agreed that this problematic had only a
weak impact on the choice of the triplet aperture (within the 20-30 mm under discussion), and the
goal of 140 mm, or even 150 mm, should be pursued.
Presentation of the WP2 activity by the task leaders
The floor was then given to the task leaders, B. Holzer for the optics & layout task (task 2.2), M.
Giovannozzi for the non-linear dynamics task (task 2.3), and E. Metral for the task related to
collective effects (task 2.4). In the absence of a beam-beam task leader (task 2.5), this activity was
not discussed. As explained by S. Fartoukh, the aim is to build the WP2 Gantt Chart, with clear
deliverable and delivery dates. This exercise will be an iterative process which might take 2 or 3 task
leader meetings.
The organisation of each task is relatively well-advanced, with contact already taken with all the labs
and agreements reached for the specific work to be delivered by each partner (see slides by the task
leaders). The work already started on several fronts, in particular for the optics task after some
period of “training” for the external collaborators to get familiar with the tools and the LHC in
general, and for task 2.3 where dynamic aperture calculations are already on-going in view of
specifying the field quality of the new triplet. In a few cases, in particular for task 2.2 but not only, a
precise counting of the resources allocated is not yet completed. S. Fartoukh insisted that this
information is very important at the project level, in particular to check whether the effort of each
laboratory is equal or larger than the grant agreement.
 Action: Task leaders.
Several comments on technical aspects were given during the presentations by the task leaders,
essentially related to the very large beta-functions expected in the inner triplet (~22 km) and
neighbouring components. Concerning the optics robustness studies, S. Fartoukh commented that
the quadrupolar fringe field of the large aperture triplet quads and D1 should be addressed with
high priority. B. Holzer answered that this was indeed foreseen. O. Bruning expressed his concern
about misalignments of the inner triplet, static or dynamic. S. Fartoukh added that he mentioned
this aspect at Chamonix 2011, including targets on power supply ripples (about 0.5-1 micron for the
IT vibrations and 0.5-1 ppm for the PC ripple). Finally Oliver insisted on the need to include in the e-
cloud simulations the large transverse beam sizes reached in the inner triplet (as it is known that the
beam sizes play a role close to the threshold), and also to simulate the 2 counter-rotating beams in
this zone (or simply multiply the bunch frequency by a factor of 2). E. Metral took note.
AOB
S. Fartoukh asked the task leaders to compile a mailing list for their task and send it to Cecile. At the
time where these minutes are written, this is done.
S. Fartoukh informed the task leaders on some deadlines discussed and reported in the minutes of
the last steering committee
a) ”Lucio recommends that in view of the next plenary Steering committee of 5 April from 16h to
18h (to allow colleagues from the US to participate) each WP coordinator reviews the Milestones
and Deliverables for the FP7 Design Study.”
b) “EU strategy update: we need to write a draft by 20 March for Steve. It should be less than 20
pages, so each WP is invited to produce 2 pages. Lucio will circulate an index by beginning of March.
Deadline for Lucio and Oliver: 15 March, they will be the editors. Then, probably, a longer 60 to 80
pages document is needed for beginning of July for submission to the EU group in charge of the EU
HEP strategy update. In principle, the group will openly review this document in September and then
after a closed meeting they will make a proposal in Spring 2013 followed by an approval in a special
CERN Council meeting dedicated to EU strategy in May 2013 in Brussels. A pre-approval by the CERN
Council, in its function as manager of the CERN laboratory, maybe necessary in December 2012.”
Next Meeting 16.02.2012 (8:309:30): WP2 resource and task matrices.
Reported by S. Fartoukh