TWiki> SPL Web>Linac4Web>RFStructureMeetings>Minutes27February2009 (2009-03-06, FrankGerigk) EditAttachPDF

F.Gerigk, M. Schuh, G. DeMichele, F. Grespan

**CCDTL** (FrankGerigk)

- material specifications to the CERN Purchase Departement, to visit the forgery in 10 days
- 1 tank composed by 2 preformed pieces flanged in the central plane (helicoflex) to avoid the e-beam welding of the cylinder with end plates

**PIMS** (FrankGerigk)

- discussion between M. Vretenar and DG Heuer if the Poland manufacture could be considered an "in kind contribution". Yes, at the conditions: 1) Linac4 group responsible of the job quality; 2) Soltan Institute (Poland) should accept a price 10% less than the CERN workshop estimation

**DTL**

- Status of the circuit model (FrancescoGrespan)
- HFSS simulations to obtain value of the PC-DTube capacitance (=Cp) using Quasistatic Approximation method: for a 3 mm spacing Cp ~ 2-3 pF, increasing with the Drift Tube length (7-10-14 cm simulated)
- Different PC modes give more or less the same value of Cp, as expected
- writing of the circuit matrix as function of the DTL geometry (Gap number, PC number, PC position)

- Power coupler simulations (GiovanniDeMichele)
- MWS simulations for the DTL Tank1 power coupler show a too long interconnecting guide (11.6cm). According to a first estimation it should be reduced by about 3cm.
- At the moment the simulations take into account 80% of the unloaded Q, the worst case between the 2 methods applied for the calculation of the external Q and the beam loading.

**HOM**

- Longitudinal beam dynamics (MarcelSchuh)
- the beam dynamic routine is running!
- HOM effects on the beam dynamic is included
- small modifications were needed due to E0*T changes for non synchronous particles in comparison to Joachim Tuckmantel's code.
- Simulation with the actual SPL layout (2 sections, cavity spacing, etc.) started
- Ask beam dynamic group for latest results of bunch jitter and bunch phase space, and source experts for charge jitter in order to have a realistic input.

- HFSS simulations:
- Actual geometry of SPL cavities was analysed to get a list of HOM and their R/Q values (HFSS)
- The frequency of the acc. Mode fits well with the superfish results, but not the field (no flat top field). Geometry must be ajusted in HFSS.
- Difficult to know the real R/Q value because of the simulation symmetry planes

-- FrancescoGrespan - 27 Feb 2009

Topic revision: r3 - 2009-03-06 - FrankGerigk