2009.12.07 - Turn-By-Turn Simulations

Simulate:

• cta_2085mev_20090516.lat
• 6x6 tracking; damp 40k turns, sample 1024 turns
• Resonantly excite in a-mode (horizontal)
• Ideal lattice (no misalignments)
• 0um, 160um (TBT) resolution

Note that at 160um turn-by-turn resolution, a 1024-turn average orbit measurement will yield 160/sqrt(1024) ~ 5um resolution, or what we've measured our repeatability to be.

Plot button signals b(2,3,4) against b1.

0-micron resolution

Amplitude of oscillations over these turns:

Odds are our actual resonant excitation implementation produces a much smaller amplitude than this; in theory the nonlinearities in button signals should be of less concern.

160-micron resolution

Amplitude of oscillations is similar.

Looking at AW's 'ping' data (+/- 2mm vertical amplitude), the coherence of actual TBT data is MUCH better than the 160-micron resolution scenario simulated above. This implies that the 1024-turn average orbit resolution is limited by something other than actual BPM resolution. Possible candidates:

• Beam stability
• Magnet power supplies
• RF system