1. Status of Impedance studies
G. Arduini, R. Calaga, E. Metral, D. Quatraro, G. Rumolo, B. Salvant and many others

2. Zbase
TMCI in the SPS
Impedance assessment

3. 4 -weighed Wakefields / kicker
Two available methods
MAD-X
Kickers geometry
Kickers geometry
Twiss file
ZBase (rewall)
ZBase (rewall)
MAD-X
4 -weighed Wakefields / kicker
4 Wakefields/kicker
Twiss file
ZBase (sum)
HeadTail
With
Lattice
4 -weighed Wakefields
HeadTail
Coherent motion
Coherent motion
See Diego’s talk for more details

4. ZBase : what to do next Urgent: A bit less urgent:
Include other SPS elements and calculate the wake fields (simulated RF cavities, IPMs, BPMs, beam pipe, etc.)
Include longitudinal impedance calculations
A bit less urgent:
Link MAD-X to Zbase, and not only the MAD-X output twiss file.

5. Zbase
TMCI in the SPS
Impedance assessment

6. HEADTAIL Simulations Vertical There is a beam current
range around 8e10 where the vertical is stable
and
the horizontal is slightly unstable
Horizontal

7. Vertical growth rate: Comparison between measurements and simulations
Growth rate is difficult to measure as the instability is fast and losses occur quickly

8. Measured loss pattern Stable beam  Nb  [0; 6] & [6.3;7.6] 1010 p
Unstable beam  Nb  [6; 6.3] 1010 p
Unstable beam  Nb > p

9. Simulated loss patterns
Stable beam  Nb  [0; 5] & [8;9] 1010 p
Unstable beam  Nb  [5.5; 7.5] 1010 p
Unstable beam  Nb > p

10. Measured loss pattern
0.2 sec
0.2 sec

11. Zbase TMCI in the SPS Impedance assessment
See yesterday AB seminar from Rama