Minutes of the 24th WP2 Task Leader Meeting held on 28/02/2014
Present: G. Arduini, I. Bejar Alonso, O. Brüning, R. De Maria, P. Fessia, M. Giovannozzi, R. Jones, E. Métral, T. Pieloni, S. Redaelli, H. Schmickler, A. Valishev, A. Wolski.
Minutes and Follow-up of Actions (Gianluigi)
The first two presentations have already been given at the Task 2.4 meeting on Wednesday 26/2. The third one will be presented during this meeting.
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P. Fessia has discussed with the colleagues for the aspects related to the integration of the crab cavities and he will show a couple of slides presenting the status of the integration and proposals for discussion.
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A meeting is going to take place to discuss the status of the Beam-Beam module implementation in SIXTRACK and the next steps is going to take place on 6/3.
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Riccardo will circulate an example of the output files generated by SIXTRACK with the information on the input parameters used for the simulation (after the meeting the example was put in http://sixtrack.web.cern.ch/SixTrack/www/sample/bbe52/fort.6).
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The reduction of the D1 magnetic length from 6.7 to 6.3 m has been approved by PLC at the last meeting (18/02/2014).
Input required from WP2 for the Beam-Beam Long Range Compensator (BBC) – H. Schmickler
Oliver asked whether the dump can be used as single pass halo monitor. This should be investigated.
Gianluigi added that one should look also at the core evolution to study the impact on luminosity.
Stefano added that collimators could also be used to study diffusion and halo generation.
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Optimization of BBC parameters for HL-LHC. Hermann sees that this activity should start form 2017 onwards. Gianluigi noted that this activity should start now to evaluate the expected impact of the BBC on HL-LHC performance. Sasha noted that a factor two improvement in dynamic aperture is expected for flat optics according to the simulation he has shown at the Crab Cavity workshop in December.
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For the integration studies, one should try already to study integration to down-select some options.
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Hermann raised the question whether a global compensation could work. Oliver replied that if the resonances of various order have to be compensated, the phase advances will over-constrain the required position.
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Gianluigi asked a review of the simulations done so far. This is already being organized within task 2.5. Action: Tatiana and Sasha to organize a meeting to review the results of the studies conducted by T. Rijoff. Action: Tatiana, Sasha.
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Hermann would like to trigger a detailed specification of all the new instruments as it was done for the LHC.
Aperture constraints from optics considerations – R. De Maria
Riccardo reviewed the aperture requirements from optics considering the nominal optics and the flat optics with *=30/7.5 cm in the crossing/aperture planes.
At present we can expect that all apertures exceeding 12 sigmas (based on the updated definition of the tolerances for the apertures being documented in a note) can be protected by the collimation system. A few areas in the triplet (Q2/Q3), D2 and TAN have been identified where this criterion cannot be satisfied. The main message that should be passed is that the definition of the dimensions and tolerances of the beam screen/cold bore aperture of the triplets and D2 should be defined as soon as possible and that aperture should be gained if possible in the above areas.
Updates from Task Leaders – O. Brüning, M. Giovannozzi, E. Métral, T. Pieloni, A. Valishev
Task 2.2 (Massimo)
Nothing to report.
Task 2.3 (Massimo)
Nothing to report.
Task 2.4 (Elias)
Nothing to report.
Task 2.5 (Tatiana)
Nothing to report.
Task 2.6 (Oliver)
Nothing to report.
There was no time to circulate the slides from P. Fessia concerning the status of the integration of the crab cavities. Paolo will circulate them by e-mail.
Future topics will be:
Reported by Gianluigi and Riccardo.
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