Technical Board Meeting TESLA Technology Collaboration Meeting Orsay, June 16th – 19th, 2009

Charge for the Technical Board Members of the Tesla Technology Collaboration (TTC) According to the MoU of TTC the Technical Board TB shall provide advice to the Collaboration on technical activities towards reaching the goals of the Collaboration Mission. To this end, the TB will compile information on the technology activities in different technical areas, provide findings and recommendations to the CB. … The TB can be described as the technical arm of the Tesla Technology Collaboration, TTC. As such its primary duties are to carry forward the technical program of the TTC. Much of the work to the TTC is carried out in, and as a result of, the semi-annual meetings of the TTC. Working Groups focuse on technical items of current interest as defined by the CB. The TB will discuss and lay plans for advancing the issues under consideration. Some activities of the TB and its members will be self-assigned while some will result from responses to requests from outside by leaders of the various projects which depend on superconducting RF.

TTC Technical Board Cavity: P. Kneisel (JLAB) L. Lilje (DESY) D. Reschke (DESY) K. Saito (KEK) R. Laxdal (TRIUMF) Coupler: E. Kako (KEK) W.D. Moeller (DESY) Module: N. Ohuchi (KEK) C. Pagani (INFN) P. Michelato (INFN) B. Petersen (DESY) T. Peterson (FNAL) T. Arkan (FNAL) Linac and and Integration: H. Edwards (FNAL) S. Michizono (KEK) S. Simrock (DESY) H. Weise (DESY) Chair Ex-Officio (per TTC MOU) Spokespersons of major test facilities TTF / FLASH: S. Schreiber ILCTA-NM (old SMTF): S. Nagaitsev STF: H. Hayano

TTC Technical Board Guests: O. Napoly (IRFU, CEA Saclay) N. Toge (KEK) M. Ross (FNAL) A. Yamamoto (KEK) Y. Yamazaki (J-PARC, KEK&JAEA) J. Mammosser (SNS) D. Proch (DESY) B. d’Almagne (Orsay)

General studies / common topics At the last TTC Meeting the TB decided to support the HF free electro polishing studies done at INFN Legnaro. CEA Saclay had/has also interest in further EP R&D and is looking into Buffered EP. For the latter R&D line see the talk of F. Eozenou / Saclay. For the first we unfortunately have no recent information and hope for the SRF workshop. Excitation of other pass-band modes was observed in many cavity tests. So far there is some understanding of the excitation mechanism. Is it multipacting? Where? Which modes are excited when / under which conditions? KEK and DESY have presented their findings. The DESY results are going to be published at the SRF workshop. The TB suggests to consider a summary report given at the next TTC Meeting together with a TTC Report. Since the last TTC Meeting some progress was made wrt. pressure vessel certification. We have some additional information from all three regions. The TB will ask the relevant TB members to take care of the preparation of an overview at the next TTC Meeting. Participation in ILC GDE discussions is assumed. Concerning the usable gradient the acceptable field emission limit was discussed. It was suggested to define a calibration procedure for existing Vertical Test Stands, i.e. a calibration source. Marc Ross is going to check if FNAL can work on this. The gradient yield is important for all larger projects since lots of money is involved here. The TB supports the clear distinguishing between process and production yield. The definition of both exists. Important: whenever the definition can not be used in the strict sense, explanations should be listed together with the yield plot. The key issue is: why to exclude which cavities from the statistics?

General studies / common topics (cont.) Around 2005 an overview about existing Cavity Preparation Infrastructure was produced. Since then two tables were established (KEK and within CARE, the EU funded projects). An update should be made for the next TTC Meeting with the help of the tables’ authors. Whenever projects arrive on the real axis some excellent R&D plans have to be stopped or paused. The TTC Meetings should be used to present the status of such activities with the hope that the baton can be passed to ‘some good friends’ in the SRF community. The TB would be happy to include more low beta cavity issues. As also discussed in the Collaboration Board the TB’s expertise should be strengthened as soon the relevant colleagues become regular participants of the TTC Meetings.