2023-03-10
RF noise check without amplifer to test different AWG clocks. This is to double check that the noise level and harmonic compenents is the same as yesterday before we make any changes to the setup.
We are now going to bring the scope and place it next to the FAB.
When we initially connected the FAB to the scope a few meters away, without amplifier, the amplitude of the noise was +/- 5 mV. The RF was at its full amplitude. At this point the connection between the FAB and scope comprised two connected cables. Add the filter to the scope helped somewhat. When we removed one of the cables, and with a filter attached to the scope, the noise amplitude dropped to +/1 mV.
We can acquire scope data from the control room over the ethernet cable. A camera was also used We took data in the middle of flattop with the RF voltage at various levels. The amplifier was not connected and without beam.
After lunch, we took FAB data without RF. As before the amplifier was not connected. We then went down to the machine to connect the amplifier. WIth RF on, and with the scope next to the FAB, the noise level is +/- 20mV.
16:00 We reconnected the amplifier.
16:10 scope setting, Channel 1 (FAB): 100mV per div. 20ms scope window. 0.8ns on C1.
16:33 Channel 1 (FAB): 200mV per div
Comparison of signal integral at 35 MeV and 56 MeV.
Data from 9/3/23. File index 0 (35 MeV flattop) and 23 (56 MeV flattop). Beam on and amplifier connected in both cases. Unfortuately, we didn't take data with a 400ms window in the 56 MeV case so we can only compare the first 200ms.
5000 turn moving window used for averaging in both cases.
Spectrum in 35 MeV flattop case
Data from 9/3/23, file index 0. Beam on, amplifier connected. Note h=6 is dominant noise harmonic.
Spectrum in 56 MeV flattop case
Data from 9/3/23, file index 23. Beam on amplifier connected. Note h=5 is dominant noise harmonic.
Spectrum in 35 MeV flattop case (beam on)
Data from 9/3/23, file index 0. Beam on, amplifier connected. Note h=6 is dominant noise harmonic.
Spectrum in 35 MeV flattop case (beam off)
Data from 9/3/23, file index 3. Beam OFF, amplifier connected. Note h=4 and h=4 now dominate.
Same data as above, but on a log scale.
Slope of lines estimated from the points shown. This gives a decay time of 396ms in 35 MeV case and 569ms in 56 MeV case.
Plots similar to below for files 34 through 103 for harmonics 1 to 12 are on the teams under Beam Stacking Experiment - see link.
FILES 38 AND 68 BELOW (47 ms After debunch) 10ms window
Zoom to harmonic 7
FILES 44 AND 74 BELOW (177 ms After debunch) 10ms window
ZOOM into harmonic 7
FILES 56 AND 86 BELOW (577 ms After debunch) 10ms window
Below using AWG script with 40 MS clock. Looking at h=7, 35 MeV. Window is 20 ms. (left) beam on, (right) beam off.
37-57 ms (#92, #98)
67-87 ms (#93, #99)
167-187 ms (#94, #100)
267-287 ms (#95, #101)