2009 TESLA Technology Collaboration Meeting at Orsay CB Report Yoshishige Yamazaki TTC Chair J-PARC, KEK & JAEA 18th June, 2009 LAL University of Orsay Orsay, France 1

TTC CB (1) 17th June, 2009 17:30 to 18:40 1. Approval of minutes of last CB meeting. The printed minutes are distributed to the attendee, being unanimously approved. 2. Proposal to invite the Executive Committee (EC) members, Marc Ross and Nobu Toge, to join the CB meeting as observers is approved unanimously (the head of the TB, Hans Weise, has been already invited, while one more EC member, Olivier Napoly, is a CB member). 3. Selection of the new deputy chair (D.Proch will retire).

Dieter Proch It is to have been really guiding TTC. Here, let’s thank him for his Great Contribution to TTC, SRF Technology, and SRF Community World-Wide.

TTC CB (1) 1. Approval of minutes of last CB meeting. The printed minutes are distributed to the attendee, being unanimously approved. Proposal to invite the Executive Committee (EC) members, Marc Ross and Nobu Toge, to join the CB meeting as observers is approvedunanimously (the head of the TB, Hans Weise, has been already invited, while one more EC member, Olivier Napoly, is a CB member). 3. Selection of the new deputy chair (D.Proch will retire). The Chair proposed John Mammosser, SNS, as new deputy chair of TTC. After a short discussion this proposal was accepted unanimously by the CB. John Mammosser was called in. He appreciated the offer and expressed his willingness to accept the position of TTC deputy chair.

TTC CB (2) 4. Proposal of forming a New Board, referred to as “Scientific Board (SB)” or “Advisory Board (AB)”. The proposal is as follows. The mission of SB comprising the three members is to support the chair and deputy chair by suggesting the scientific TTC activities for electron, proton and low-beta SRF accelerators, respectively. This is necessary because TTC wants to extend its mission to the low-beta and proton linac. The scientific careers of the SB members should be competitive and be recognized by the world-wide SRF scientific community. The discussion on this proposal is as follows. One more board may complicate the TTC organization. The above mission should be covered by strengthening the TB. Actually, the low-beta SRF expert already joined the TB from the last meeting, which involved many Indian institutes interested in the low-beta SCC. Although the TB should cover the low-beta and proton SRF, the chairmanship should be also strengthened to cope with this trend. The proposal was finally approved by CB. The candidates will be soon nominated by close discussion between the chair and deputy chair.

TTC CB (3) 5. Discussion about the next TTC meetings: 5.1. Should we continue with 2 meetings per year? Considering the fast progress in SCC technology, it is still ideal to have the meeting held every 6 months approximately. However, the reality is that we could hold it nearly every 8 months or so, in order to avoid other meetings. 5.2. Should we continue with the rotation: EU-US-EU-Asia-EU? We have still more institutes committed in EU than US and Asia. So, we should continue this rotation for the time being. 5. 3. How to avoid overlap with other meetings? This has been always a big issue to solve, depending upon the specific situation. No general rule is possible. 6. Discussion about the next TTC meeting: location and time The next turn is North-American institute. FNAL volunteered to host the next meeting. However, 6 months later from now is December. Chicago’s winter is not a good season for travelers; heavy snow showers delaying/canceling flights quite frequently. So, the next meeting could be hold during March or April. The deputy chair investigated the schedule of other meetings to make a final decision for the dating, closely contacting with the meeting host. 7. Everybody agreed to tighten connection to the low beta and proton accelerator community. How to do it is an issue to need more discussion, but just try for the time being.

Questions or Comments ? Here

The Biggest Issue to solve for proton SC Linac (Chair’s personal view) The phase/amplitude accuracy (typically one degree and one percent) of each cavity in the proton linac is much higher than electron linac, since even the 1-GeV proton is not completely relativistic. The errors excite the synchrotron oscillation and/or mismatching longitudinally. The space charge force together gives rise to the halo formation, resulting in the beam loss. Also, the control of Dp/p is vital for ring injection both in deviation and distribution. At the ESS meeting held in Ancona, a long time ago, where the ESS began to think about the SC linac seriously, I proposed that one cavity per one klystron is a must under the influence of Lorentz detuning and microphonic one, whatever expensive it is. SNS cleverly took this scheme (perhaps independenly, since anybody thinks so). Since this scheme is too expensive for future multi-GeV linac, we have to develop reliable piezo-tuning technology, or cavity stiffening, or some innovative idea to realize multi-caivty per klystron scheme (J-PARC has been developing two cavities per one klystron system, making use of the cavity stiffening).

The Biggest Issue to solve for low-b, high-intensity SC Linac (Chair’s personal view) In order to mitigate the space charge force, we need frequent focusing both longitudinally and transversely, at the low-b section. This is one of the reasons why SNS and J-PARC chose high-frequency RF system. Therefore, the biggest challenge in the low-b structure is how to efficiently shield or prevent the magnetic field of the focusing magnets from influencing the superconductivity. In other words, how close can we place the focusing magnets to the superconducting caivities is a challenge. Of course, the reliable production of the complicated SC structure is a big challenge as you know well.

LINAC10 Conference to be held in Tuskuba In contrast to a big IPAC, the LINAC is like this meeting, having all sessions plenary and enabling the detailed, real discussion. Conference web site has been setup at http://linac10.j-parc.jp/

Outing to Nikko in LINAC10 The world famous Toshogu Shrine Kegon waterfall Nikko is one of Japan’s most popular destinations of tourists. It is famous of Toshogu shrine and the beautiful natural scenery. Lake Chuzenji

Outing to Nikko (cont.) Existing highways Nikko New highway Tsukuba ~70 km Tokyo A new highway opened last winter connecting two existing highways. With the new highway, we can gofrom Tsukuba to Nikko without going through Tokyo area. It shortens the travel time to ~1.5 hour, and reduces the risk of delay in schedule due to traffic jam.

for their Excellent Meeting Organization and Hospitality At the end, Let’s Thank Bernard and his Staffs for their Excellent Meeting Organization and Hospitality

Let’s Meet at Chicago Sometime And Let’s Meet at Chicago Sometime between this Winter and Next Spring