Summary of the Collaboration Meeting at CERN, 22 August 2013

Participant Institute Responsibility Email
Pawel Krawczyk NCBJ general manager
Frank Gerigk CERN project coordination
Rolf Wegner CERN project coordination

News and production status at NCBJ, summary:

  • The contract with the external company CPL has been terminated as jointly decided with CERN due to serious quality issues and frequent delivery delays of several weeks. The production will be taken over by NCBJ. The PIMS copper pieces have been transferred back to NCBJ.
  • P. Krawczyk showed the Status of PIMS production including remaining space parts. Good progress has been made for disc production while rings need to be welded.
  • Due to a vacuum problem of the furnace, there is unfortunately a major delay in the completion of the last remaining elements of the 1st cavity, cavity M. According to the previous planning ( the finalisation of the last elements of cavity M at NCBJ was foreseen in week 24 (16 June). The new date of finalisation is foreseen for week 42 (20 October). The delay was caused by several factors: A late delivery from CPL in unacceptable quality, the time needed for repair before brazing, the discovery of a vacuum leak at the temperature probe inside the furnace and a 4 week delay for the furnace repair service. Unfortunately, CERN has not been informed of the furnace problem as a solution to braze the waveguide ring of cavity M at CERN would have been investigated.
  • The new machine, Chiron Mill FX800, has been received and installed. Staff will be trained next week. Thereafter, in weeks 36-39 it is foreseen to machine test pieces in aluminium before working on PIMS copper pieces from week 40 onwards. For the machining strategy, it was proposed to start conservatively again machining a PIMS copper piece to final tolerances with an otherlength of +1 mm.
  • With the new machine, the production capacity can be doubled from October onwards. Additionally, a 2nd shift is foreseen from October onwards and a 3d shift can be considered if necessary to keep the planning.
  • NCBJ is optimistic to complete 4 PIMS cavities in 2013 as foreseen so far.


  • In the present schedule it is foreseen to braze 36 tuner ports DN63 for rings in the week before brazing the waveguide ring. A change of order has been discussed but in order to avoid risks for the waveguide ring compared to a small gain in time it has been agreed that the proposed order is a good choice.
  • The rough machining of a 2nd waveguide ring has been discussed. The risk is if the brazing of 1st WGring fails and the decision is taken to braze all WGrings at CERN, the rough machined 2nd ring is not compatible with vertical brazing. The benefit to start already the 2nd WGring is that the machine for rough machining is available at the moment. Moreover, as the completion of cavities in 2013 will be limited by WGrings, the rough machining of a 2nd WGring will speed up the cavity finalisation. So the decision was taken to give the green light for rough machining of a 2nd WGRing.
  • For the organisation of activities at CERN (metrology, assembly, RF tuning, re-machining of tuning islands, cleaning, welding) it is important to have reliable schedules. A milestone for the Linac4 project is the Linac14 conference in Geneva when Linac4 will be shown to the conference participants. A delay in the PIMS production will be quite visible, since we expect to have most of the other structures (DTL + CCDTL) installed in the tunnel by that time.

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  • CERN and NCBJ: establish a phone meeting once a week at a fixed day and time to improve the information flow
  • NCBJ: Proceed quickly with the port welding of rings. Problems with welding have been seen for cavity M where 2 rings had to be replaced.
  • NCBJ: implementation of shift work to catch up on the lost time.

Comments during approval:

  • Marcin.Wojciechowski: OK, but time slot for EB welding (before end of week 44, if parts delivered on week 40-41) not yet confirmed by FZJ.
  • Marczenko Marek : A third shift is not advised due to the required precision for final machining and lack of the necessary staff at the moment

Rolf Wegner, 27. August 2013
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Topic revision: r4 - 2013-09-17 - RolfWegner
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