Impedance RF Measurement Coffee Meeting Minutes

November 7^th, 2008

1) Current status of the impedance task force:

• Theory: Elias Metral, Benoit Salvant, Bruno Zotter
   
• Simulations: Alexej Grudiev, Federico Roncarolo, Bruno Spataro, (Carlo Zannini? to be discussed with Giovanni)
   
• Measurements: Mike Barnes, fritz Caspers, Federico Roncarolo, Benoit Salvant
  
   

2) Foreseen PAC09 papers:

• 1st  paper: Phase II collimator studies (main author: Elias)
   
  • Study of materials with various epsilon (Elias's theoretical calculations + Alexej's simulations)
     
  • We should mention that the coil does not measure the electrical field and is therefore not suited for dielectrics.
     
  • Study of geometries that decrease the conductivity (waffles, grooves)
     
  • Study of resulting instabilities and tune shifts
     

   

• 2nd paper: SPS kicker (main author: Mike Barnes)

• measurement and simulation procedure in frequency domain by Elias et al
   
• simulations by Alexej et al
   
• measurements by Mike et al

• 3rd paper: SPS BPMs (main author: Bruno Spataro)

• measurement and simulation procedure in time domain by Elias et al

• simulations by Bruno S. et al
   
• measurements by Fritz et al

 

In addition, a PRST/AB paper foreseen on collimator impedance theory, simulations and measurements

3) AOB

• There will be no student from Daresbury to work with Fritz on phase II collimation
   
• It is important to understand what is involved in "cryogenic collimators" (see J. Jowett's talk at LCU section meeting).
   
• We should be careful with electric boundary conditions for kickers, that should be wrong at low frequency. We should use magnetic boundary conditions.
   
• The name of the webpage gets rather irrelevant as the bench measurements are not the only aim of the webpage anymore. We should find a more generic name that reflects the fact that FEA simulations and EM theory are also used to assess the beam impedance.
   

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