PIMS collaboration kick-off meeting, 16-17 November 2010 at CERN


Soltan Institute for Nuclear Studies (IPJ):
Jan KOPEC (Head of production unit), Pawel KRAWCZYK (General manager), Marek MARCZENKO (PIMS mechanical construction), Marcin WOJCIECHOWSKI (IPJ Technical coordinator for PIMS collaboration), Grzegorz WROCHNA (Director of IPJ), Slawomir WRONKA (Group leader accelerator studies)

Forschungszentrum Jülich (FZJ):
Wilfried BEHR (Head of electron beam welding section), Michael PAP (Head of Joining Techniques)

Alessandro DALLOCCHIO (PIMS mechanical design), Gilles FAVRE (PIMS mechanical construction at CERN), Luca GENTINI (PIMS drawings), Frank GERIGK (Linac4 accelerating structures, Technical coordinator for PIMS collaboration), Jean-Michel GIGUET (Installation & Testing), Dante GREGORIO (Collaboration agreement & financial aspects), Rolf HEUER (CERN Director General), Mark JONES (Large Scale Metrology), Tadeusz KURTYKA (Project Office, International Collaborations), Serge MATHOT (Section leader of "Assembly and Forming"), Dominique PUGNAT (Metrology), Benoit RIFFAUD (PIMS support and wave-guide coupler), Patricia UGENA TIRADO (PIMS Electromagnetic simulations), Maurizio VRETENAR (Linac4 Project leader), Rolf WEGNER (PIMS design and testing), Sylvain WEISZ (Linac4 Technical Coordinator)


List of talks, link to INDICO site

1. Mechanical Design

2. Transport & Packaging
3. Financial and Contractual Aspects
4. Planning
5. Action List
6. Annex

1. Mechanical Design & Construction

Presentation by A. Dallocchio and presentation by G. Favre.

1.1 General principles

  • The straightness of the beam axis of a completed cavity has to be within ±0.3 mm.
  • There are 3 types of discs per cavity (end disc, the discs around the centre cell, and the other discs).
  • There are 3 types of rings (central ring, ring with pick-up port and tuner port, ring with tuner port only).
  • Cooling pipes are drilled radially. There is ~1 cm between pipes and vacuum and it is important to maintain the given angle and depth of these pipes, both have to be checked with calibrated bars or a comparable method.
  • The orientation of the coupling slots changes from disc to disc by 90 degrees (see SPLACPMZ0009).
  • Quality control must make sure that all geometries and tolerances are met, and that the pieces are not damaged during handling.
  • The last cavity has a larger beam pipe diameter (cavity N)!
  • CERN will provide spare material for one extra cavity.
  • In total 12 cavities need to be built.
  • CERN will need some auxiliary pieces, which were not included in the original price estimate. IPJ is ready to construct these but CERN needs to clarify und what kind of agreeent these pieces can be built.

1.2 Drawings

  • CERN provides "specification" drawings for the prototype (SPLACPMB...) and "specification" drawings for the 12 cavities (SPLACPMC.. to SPLACPMN) to be constructed within the collaboration.
  • Some drawings have a nomenclature: SPLACPMZ... For IPJ these shall be considered as "specification" drawings, because they show the final dimensions of the pieces, which CERN wants to receive. From the CERN point of view, however, these drawings are considered to be "method" drawings because they contain for instance an "overlength" to account for the weld shrinkage during the final orbital weldings of discs and rings.
  • For information CERN provides all "method" drawings for the prototype (SPLACPMT...). IPJ can adapt these methods to its own production methods, but any changes in the production procedure must be discussed with CERN.
  • Each drawing has engraving table, which indicates how to label each ring and disc of each cavity. These labels are needed to differentiate pieces of different cavities and to put the pieces of each cavity into the correct sequence. (see SPLACPMZ0009).
  • The drawings of different ring types are functional (no indication of manufacturing procedure for EBW of tuner ports).
  • Concentricity and perpendicularity is given with respect to beam axis (slide 10, bottom right).
  • IPJ wants 3D models of all parts for CAM and metrology programming.

1.3 Tolerances

  • Tolerances are defined for all surfaces, either within a general tolerance table or they are directly indicated on the surfaces within the drawings.
  • Discs:
    • External reference planes are used for metrology and are used to find the beam axis once the cavity is assembled. There are tight tolerances on the outer diameter of discs and rings. These outside surfaces are used to clamp disc and ring into position for welding. Very tight tolerances in the disc-ring contact areas are needed for a precise fitting of discs and rings.
    • The reference for the tolerances on the disc is the beam axis (centre of both noses).
  • Rings:
    • There are no detailed tolerances given on the tuner ports. FZJ has to prepare their own "method" drawings for these. FZJ is free to use the CERN prototype method drawings as a blueprint.
  • Surfaces for Helicoflex joints: Here a circular surface roughness of RA 1.6 is needed to achieve leak tightness: beam pipe connection on the end discs.

1.4 Water connections

  • All threads are work-hardened (by a certain amount of plastic deformation during the threading).
  • All threads are slightly chamfered by &plusm; 0.2 mm. This is needed in order not to damage the sealing joints. The chamfer must not be larger, because then the joints will no longer be water tight!

1.5 Quality control

  • For metrology of the discs measurements with laser tracker targets (provided by CERN) have to be done on 6 points on the outside of each disc. These points then have to be referenced to 2 points on the beam axis. It is important that the outer reference points are on the targets and not on the outer surface of the discs! The names of the reference points correspond to the numbering of the pieces,
  • It was agreed that FZJ makes a welding test of a port on a flat copper sheet, which shall have the same thickness as the final pieces. CERN will provide the machined pieces.
  • It was agreed that IPJ makes a machining test of a disc. For this purpose CERN will provide either low quality copper of sufficient size, or if available a piece of 3D forged copper. It is understood that a machining test on low-quality copper will lead to stronger deformations during machining.
  • The reference system for the metrology measurements changes its orientation from disc to disc. This system was introduced in order to have one common orientation for metrology for the assembled cavity.
  • The reference temperature for machining and metrology measurements is 20 deg C.
  • For the 500 mm diameter the length change with temperature is ~0.01 mm/deg C.
  • A 1 mm measurement stylus is needed to measure the orbital strip of the clamping areas.
  • Metrology of water channels: a stylus of 200 or 260 mm is available at IPJ, which could be used for the position & orientation measurement of the water channels. The depth can be measured with simple bars or with gauges.
  • Deformation of rings during metrology the force needed to deform a ring by 0.4 mm is 17-23 kg (with the internal stress <30 MPa). That means that if the measurements of the rings are done horizontally, the results should remain the same, even if the pieces are moved and re-measured.
  • X-ray testsIt was agreed that all weldings of the first cavity are X-ray tested. If no defaults are found, then 10% of the remaining pieces will be tested. If defaults are found, X-ray testing of all pieces will continue until the pieces have reached specifications.

1.6 Construction principles

  • The central ring is the only piece that is thermally treated to avoid deformations during the brazing. The cental ring is the only large piece per cavity, which is brazed.
  • High precision machining (~20 um) is important to achieve the required RF characteristics. The surface quality is key for power efficiency of the cavities.
  • The construction must follow standards for UHV equipment.
  • Stainless steel flanges on tuner ports are brazed onto ports before welding.
  • ring type 3: the backing support on the tuner ports will be machined after welding and should remove the bottom of the root. After machining there should be a smooth surface on the inside of the cavity (see slide 8).
  • The stress relaxation of flanges is done at 950 deg, 2 hours.
  • The brazing of the central ring is done with the ring in upright position ( slide 37).
  • Rough machining is always done with an oversize + 1 mm.
  • The welding of ports is done from the outside of the rings.
  • The weld penetration has to deep enough to enter into the backing support. On the drawings no specific depth is given. CERN will provide its welding parameters for the ports to FZJ.
  • The cleaning is a "degreasing". No degreasing can be done on parts, which are already brazed or welded to avoid the trapping of liquids in the pores.
  • Central ring big flange: has to be manufactured like all other stainless steel flanges with the following steps: raw machining, stabilisation, fine machining.
  • Central ring2 stabilisation steps were done with heat treatment in a vacuum oven.
    • brazing of central ring: first the 2 ports (stainless steel flanges on the 2 ports), 2nd step all the other brazings, first temp: 800 deg, 2nd step at 783 degrees,
    • the central ring is very fragile due to the heat treatments and special care needs to be taken for handling and transport, to avoid damage of the surfaces,
  • a tolerance of 20 um is needed on the outside of the discs and on a strip on the rings, which will be in contact with the discs when they are clamped together,
  • no high precision is required for the position of the ports,
  • when the rings were taken off from the machines a small ovalisation was observed with a maximum variation of up to 0.18 mm in radius. This ovalisation is corrected when the rings and discs are fitted together with a tool.
  • A twist of the rings is not acceptable since it cannot be corrected!
  • IPJ will use milling instead of turning to achieve the outer diameter on the discs and rings. This was accepted by CERN.
  • IPJ will make a machining test on a disc before starting the series production. The first piece should be machined with oversize to see if the tolerances can be achieved. Once this step has been mastered the piece should be machined to its final dimension.

2. Transport and Packing

  • Each piece will be packed in a bag filled with nitrogen and then each piece is packed in one wooden box and blocked into position to avoid movement in the box during transport. Nitrogen bags are not necessary for the transport between IPJ and FZJ, but a single box per piece will still be used.
  • When the pieces arrive at CERN they will remain in the wooden boxes until they are taken out for the acceptance tests.
  • The 1st cavity will delivered separately. All remaining cavities will arrive in batches of 2-3. Empty wooden boxes will be taken back, so that they can be re-used for the next transport.
  • It is likely that IPJ will organised the transport with a truck owned by IPJ.
  • A transport insurance will be taken for all transports.
  • Transports should be organised point to point, and not be bundled with other transports as it is often done by commercial companies to reduce cost. A point to point transport is strongly recommended to avoid theft of the copper.
  • The collaborating institutes are reponsible for safe storage of the copper pieces. Theft of copper pieces has the risk of delaying the projects by 6-10 months!
  • Altogether 5 fixed tuners are needed as spares. CERN requested that the spare tuners be sent with the first cavity, since the spares are needed for the RF tuning.

3. Financial and contractual aspects

Several points have been clarified in the collaboration agreement by D. Gregorio:
  • 1.5 Clarified that the pre-series is part of the full supply.
  • 4.2 Clarified that the 83 k€ payment to FZJ is included in the total amount of 871 k€, which is paid by CERN to IPJ.
  • IPJ and FZJ need to set up a separate agreement according to the terms negotiated by CERN with FZJ.
  • 4.2.2 Cavities will be accepted one by one, and the payment by CERN will be done accordingly.
  • The intitial payment by CERN to IPJ was increased from 10 to 16%.
  • 4.2 may have to be re-phrased according to recommendations from the IPJ legal section to avoid that IPJ has to go to tender for the EBW works at FZJ.
  • 4.3 was deleted.
  • 6 Cavities will be delivered in batched of 2-3 at a time (also to FZJ).
  • "execution drawings" has to be re-named to "specification drawings"
  • feedback from IPJ is needed within 2 weeks, so that the contract can be finalised and signed before the end of the year.

4. Planning

  • The overall production time is 18 months. A detailed planning will be prepared by IPJ until the next meeting.
  • The next technical meeting shall take place at CERN between December 13 and 15.

5. Action list:

action institute/person status/result completed
provide metrology report of pieces before welding CERN, D. Pugnat done all with restricted access! overview: EDMS 1064713, detailed reports: 1064237, 1063578, 1063588, 1064156, 1063440, 1063357, 1064094, 1064302, 1064169, 1063066, 1063064, 1064105, 1064183, 1064175  
provide machined pieces for welding test at FZJ CERN, R. Wegner done 2010-12-09
perform welding test of port geometry FZJ done 2011-10-07
provide material for a machining test of a disc CERN, R. Wegner done 2010-12-09
perform machining test of disc IPJ pending  
provide specifications for machining liquids to be used at IPJ IPJ done see presentation  
detailed production schedule (including transports) IPJ done see talk at 2nd technical meeting " target="_blank">http://indico.cern.ch/event/PIMS2]] 2010-12-13
organise next technical meeting at CERN in December CERN, F. Gerigk done 2010-12-09
provide method drawings for prototype CERN, L. Gentini, A. Dallocchio done see EDMS 1109032 2010-12-14
provide brazing temperatures, times and alloys for the CERN prototype CERN, S. Mathot done INDICO meeting PIMS2 2010-12-08
provide pictures of prototype brazing CERN, S. Mathot done see below 2010-11-24
provide CERN welding parameters for ports to FZJ CERN, T. Tardy done EDMS 1107203 2010-11-24
send updated version of the collaboration agreement to IPJ/FZJ CERN, F. Gerigk done 2010-11-18
provide 3D models for all parts to IPJ CERN, L. Gentini, A. Dallocchio done EDMS 1109032  
provide set of missing drawings for cavity M and 1 drawing for cavity N CERN done Drawings3.zip 2010-12-01
assemble list of auxiliary pieces, which were not included in the original agreement CERN done  
find contractual model for construction of these pieces at IPJ CERN pending  
price estimate for additional pieces IPJ pending  

6. Annex

A1. Pictures of brazing of central ring and fixed tuners

IMG_1687.JPG IMG_1739.JPG
IMG_1738.JPG IMG_1676.JPG

A2. Supporting documents in EDMS

A3. Group photo

From left to right: Marek MARCZENKO, Marcin WOJCIECHOWSKI, Sylvain WEISZ, Slawomir WRONKA, Grzegorz WROCHNA, Jan KOPEC, Frank GERIGK, Pawel KRAWCZYK, Michael PAP, Wilfried BEHR, Rolf WEGNER

-- FrankGerigk - 18-Nov-2010

Topic attachments
I Attachment History Action Size Date Who Comment
JPEGjpg CERN171110_PIMS-kick-off_34.JPG r1 manage 2032.1 K 2010-11-22 - 15:12 FrankGerigk  
JPEGjpg IMG_1676.JPG r1 manage 2140.9 K 2010-11-22 - 09:27 FrankGerigk  
JPEGjpg IMG_1687.JPG r1 manage 2252.0 K 2010-11-22 - 09:26 FrankGerigk  
JPEGjpg IMG_1738.JPG r1 manage 2385.5 K 2010-11-22 - 09:27 FrankGerigk  
JPEGjpg IMG_1739.JPG r1 manage 2021.6 K 2010-11-22 - 09:26 FrankGerigk  
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