Last night, the FAB was successfully installed in a new location, further away from the RF cavity. We started by looking at bunched beam, flattop at 35 MeV. We could see a drop in the signal consistent with earlier observations when 4th harmonic was filtered out. This gives us confidence the RF noise is lower than before. Zooming in on the signal, a high harmonic fluctuation on the fundamental frequency can be see (harmonic may be somewhere in the region h=6  to h=8). We repeated this at 56 MeV flattop with similar results.

The spreadsheet which logs experiments, stored in Teams in the folder for today, refers to a delay, e.g. delay 200ms. This refers to a delay with respect to the trigger. The trigger corresponds to the injection time, i.e. 0ms is at injection. A delay of 200ms moves the zero point of the scope time to a point 200ms later than injection.

Data analysis shows that harmonic 6 is strong in the new FAB location. See figures below.

Coasting Beam Lifetime Measurement

#84:Beam ON, 50ms delay, 8ns/pt, 20MS/s clock, 200ms on scope.

#81:Beam ON, 100ms delay, 8ns/pt, 20MS/s clock, 200ms on scope.

#78:Beam ON, 300ms delay, 8ns/pt, 20MS/s clock, 200ms on scope.

#61:Beam ON, 20MS/s AWG clock, 700ms delay on scope trigger, 8ns/pt, 200ms on scope screen

1. The data#86&83, there are debunching and rebunching periods. 

2. I apply FFT on both periods and take both peaks.

3. Compute the ration between two peaks : Ar/Ad where Ar is the peak amplitude(fft) in rebunching and Ad is the peak amplitude (fft)  in debunching.

4. However, the data #78 and #63, there are no debunching period in the data.

5. Therefore, I took averaged Ad on #86 and #83 (1.35811E-2) to compute the survival ratio on #78 and #63.