Minutes RF structure meeting on PIMS mechanics 22.05.2008 (draft)

present: P. Bourquin, R. De Morais Amaral, G. Favre, F. Gerigk, J-M. Lacroix, G. Vandoni, M. Vretenar, R. Wegner

attached documents:

news & facts:

  • no news from the Soltan institute,


  • Ricardo has updated the cooling simulations to include an increased distance between the cooling channels and the inner surface of the beam tube (now 10 mm). The simulations show a negligible increase in maximum temperature and stress.
  • Jean-Michel will include cooling channels in the end cells.


  • the copper tests on the LEP pieces are in progress,
  • a copper delivery has arrived, but is not certain that all the pieces for the PIMS have arrived.


  • A new hole distribution was suggested by Jean-Michel. Using this distribution and a port diameter of 150 mm, Giovanna estimated that a 400 l/s pump should be sufficient. The pressure profile is not yet calculated. For pre-pumping it is assumed that we use the beam pipe after last PIMS module.


  • Jean-Michel: the weight of the prototype (assuming 12 mm cylinder thickness) is ~650 kg, Gilles says that this should be fine for the CERN EB welding machine,
  • Jean-Michel has included the vacuum pump on the wave-guide port in the drawings (see bottom of page).
  • Pierre/Ricardo: a cylinder thickness of 7 mm seems to be sufficient, a 3D simulation and an analytic estimate gave approximately the same result, the thickness at the weld can be 5 mm. Further simulations will be done, especially to make sure that the support arms do not deform the coupling holes.
  • The weight of the wave-guide coupler does not produce any important stresses in the structure, neither on the RF port nor on the end cells (see simulations by Ricardo). Has been validated (see simulation results).
  • Rolf/Frank: the frequency shift in the centre cell, which is caused by the opening of the RF port will be compensated by re-machining the noses of the cell. This avoids to have a thicker tuning ring, which would increase the material needs for the cylinders.


  • It was agreed that the final dimensions are given to Jean-Michel by the end of June. The external drawings should then be ready by the end of September, with approbation foreseen for mid-October.
  • The planning for the workshops will include a welding test to see by how much the cells are shortened due to the welding.

next meeting

will be announced

minutes by Frank Gerigk

-- FrankGerigk - 23 May 2008


Topic attachments
I Attachment History Action Size Date WhoSorted ascending Comment
JPEGjpg HOT_MODEL_TYPE_2-02.jpg r1 manage 1096.7 K 2008-05-26 - 14:36 FrankGerigk  
JPEGjpg HOT_MODEL_TYPE_2-03.jpg r1 manage 906.5 K 2008-05-26 - 14:37 FrankGerigk  
JPEGjpg HOT_MODEL_TYPE_2-04.jpg r1 manage 992.6 K 2008-05-26 - 14:37 FrankGerigk  
JPEGjpg HOT_MODEL_TYPE_2-05.jpg r1 manage 638.5 K 2008-05-26 - 14:37 FrankGerigk  
PDFpdf PIMS_STRUCTURAL_RESULTS.pdf r3 r2 r1 manage 587.7 K 2008-05-26 - 11:16 FrankGerigk  
PDFpdf results_pims3.pdf r1 manage 219.3 K 2008-05-26 - 14:10 FrankGerigk  
PDFpdf vacuum-port-grill.pdf r1 manage 61.4 K 2008-05-26 - 08:45 FrankGerigk  
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