MD goals
- Eddy current measurements on beam radial position
Logbook entries
https://logbook.cern.ch/elogbook-server/GET/showEventInLogbook/4216975
Eddy current measurements on beam radial position
We need construct supercycles to measure the radial positions at first injection, with different spacings between cycles in the same supercycle.
For the radial positions, we need to acquire only the first trajectory, and take the average of all BPMs.
It’s important that we note down the timestamps of the cycles we want to extract the BPM data from, to easier get it from NXCALS (since BPM data can be very large).
Analysis
We will fit the analytical eddy current equation to the measured radial positions and their corresponding and perform feed-forward correction on the flat bottom for the next MD.
Supercycle design
- SFTPRO1 SFT_PRO_MTE_L4780_2025_V1
- ZERO (0,1,2 x)
- MD2 MD_26_L7200_Q20_North_Extraction_2025_V1, MD 26 GeV - 200 GeV
- MD5 MD_1inj_26_200_L814_Q20_2025_V1, 26 GeV - 200 GeV
- SFTPRO1
- ZERO (0,1,2 x)
- MD4 MD_aperture_2025_V1, 14 GeV - 200 GeV
We measure MD2, MD4 and MD5 radial trajectories immediately after injection.
The following timestamps correspond to supercycle changes:
0x ZERO
09:18:00 with stable beams
RF was off on MD4 until 09:45 (unbunched beam → no orbit data from BPMs) RF enabled on MD4.
15 min acquisitions, 44s per supercycle → 20 acquisitions
1x ZERO
change at 10:07:00
2x ZERO
Change at 10:23:30 20 Aquisitions at 10:43:30
0x ZERO Change back at 10:45:20 to acquire again MD4
3x ZERO at 10:55:00 to 11:20:00
Remove SFTPRO1 MBIs At 14:35:33 We switch off SFTPRO1 by setting MBI dyneco to end at 0 seconds, and still ramp quadrupoles on the SFTPRO1.
We still see 0.3 mm decay on the radius (going upwards) on the MD2.
BPMs
Mask out BPMS https://logbook.cern.ch/elogbook-server/GET/showEventInLogbook/4214605
masked = {
"BPH.20608.H",
"BPH.41208.H",
"BPH.41408.H",
"BPH.51008.H",
"RPH.51208.H",
"BPH.62008.H",
"BPH.62608.H",
"BPH.63408.H",
"BPH.63608.H",
}