Minutes of the SPL steering group

meeting no. 9

date: 22 May 2008

present: O. Brunner, S. Calatroni, E. Ciapala, R. Garoby, F. Gerigk, A. Lombardi, R. Losito, V. Parma, J. Tuckmantel, M. Vretenar, W. Weingarten
excused: C. Rossi


1. General news and facts
2. SPL review meeting
3. Round table
4. Next meeting

1. General news and facts (R. Garoby)

  • R. Garoby reported that the ongoing FP7 bid received very high marks by the reviewers and is likely to be supported. However, while endorsing work on SC magnets they recommended cuts in the SC RF work.
  • There are now 3 activities at FNAL, which could make use of a high-energy SC linac: HINS (High-Intensity Neutrino Source), the muon task force and projectX.
  • Within HINS there is an interesting solution for a high-power phase and amplitude modulator using coaxial wave-guide components (see R. Garobys presentation). The device is very compact compared to solutions using rectangular waveguides and seems very interesting for the SPL.
  • A new layout was sketched to supply ISOLDE and/or a possible EURISOL facility at CERN with beam. Their physical location suggests that beam can be extracted from the SPL at maximum energies of ~1.4 and 2.5 GeV, giving a maximum of 42 and 75 kW for the LP-SPL, or beams in the MW level for the HP-SPL (see presentation),
  • Even though the funding for the SPL study phase now amounts to 3 MCHF over 4 years it is clear that this amount will not be sufficient to construct a fully equipped cryo-module, which is necessary to validate the technical choices.
  • A new SPL work plan needs to be established until October, which will then be used for more realistic R&D money and manpower requests.

2. SPL review meeting

  • R. Garoby and F. Gerigk both made a summary of the arguments and came independently to roughly the same conclusion, which is a tendency towards 704 MHz. However, a number of items still need to be clarified:
    • difference in power consumption for 704/1408 MHz (action on W. Weingarten, F. Gerigk, S. Calatroni, V. Parma). W. Weingarten has re-calculated the total grid to beam power conversion efficiency for reduced "static" cryogenic losses (3 W/m) as compared to the number of the Yellow Book (13 W/m) (see presentation). It turned out that it is at 1400 MHz by about 50 percent larger than at 700 MHz, which has to be understood and confirmed.
    • make sure that the cryogenic number of Wolfgang and Vittorio fit together.
    • hard numbers on the effects of HOMs.

  • O. Brunner has contacted Thales and AFT and reported that the equipment, which was delivered to DESY for 1300 MHz, 10 Hz operation is very much at the limit of its performance (klystron: 10 MW, 10 Hz, 1300 MHz). Higher duty cycles would present a considerable challenge.
  • A reduction of the SPL gradient by 20% (25 - 20 MV/m) would increase the length of the SC part (5 GeV linac) from 425 m to 510 m. The maximum straight length before the vertical bending towards PS2 is 552 m.
  • A draft of the concluding paper should be available until July.

3. Round table

  • S. Calatroni and R. Losito are in contact with Jefferson Lab and discussed the possibility to obtain a SNS cavity for R&D purposes at CERN. The only 805 MHz amplifiers, which are available at CERN are 2 klystron pre-amps with 60 W each (info from Eric Montesinos). For tests at 2 K >150 W are needed to reach 18 MV/m or >260 W to reach 25 MV/m. For operation at 4.5 K the power needs to be ~10 times as high. It was concluded that we should ask first at CEA (action on R. Garoby) if we can procure a 704 MHz cavity, which is no longer needed. Also in that case we need to buy an amplifier, but this one could also be used later on for tests on further cavities. Otherwise we could try to get a 805 MHz amplifier on loan from another institute.
  • It was concluded that it were preferable if CEA designs and builds b=0.94 cavities instead of b=1.0.
  • The transient beam loading in Linac4 and SPL cavities needs to be checked for the latest neutrino factory chopping schemes.

4. Next meeting

June 6th, 2008, 16:00 in 866-1-D15

next general SPL meeting (tentative) July, 4th 2008, 9:00 in 354-1-001

-- FrankGerigk - 26 May 2008

Topic attachments
I Attachment History Action Size Date Who Comment
PowerPointppt SPL_SC_23May08.ppt r1 manage 3849.0 K 2008-05-26 - 17:37 FrankGerigk  
PDFpdf SPL_steering_group_May08.pdf r1 manage 898.8 K 2008-06-03 - 10:11 FrankGerigk  
PDFpdf freq-temp-comparison.pdf r1 manage 35.3 K 2008-05-27 - 14:40 FrankGerigk  
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