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Amplitude dependent optics

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28/R-015 (CERN)

28/R-015

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OMC MDs review:

#ATS + OMC
-High telescopic optics, arc optics control
   -> telescopic factor of 6.66 for FLAT?
-Flat optics Run3: beta* control (improved k-modulation)
-Offsets and betas in Q1-Q4  with k-modulation (improved analysis) -> use Totem data?

-K-modulation: arc , during the ramp

-Local coupling control: IPs and IR4
-waist scans developments
-b6 correction (first tests and validation in commissioning at 25cm ? with magnetic data)
-BPM performance monitoring: calibration + ageing (review Manfred proposal)
-New ballistic flavours: adding IR4, large horizontal and vertical dispersions in IRs, telescopic ballistic?
-Amplitude detuning with CMS solenoid on and off
-0.5 um pilot bunch from injectors for measurements and BSRT calibration
-MCS + dipole b3 misalignment studies (H & V, add bumps, after full decay)

-MCD at 50% at injection, chromatic amplitude detuning. 
-3D driven oscillations
-Ramp measurements with 3 bunches
-(60 deg phase advance optics)
- Amplitude dependent beta-beating: Ac dip method and single kick (donut) + k-modulation
-Islands Oct+Q': (emit motivation)

-ADT large single bunch kick
-(ADECTA at top energy with a fancy kick method)

-(Momentum compaction factor by measuring tune Qs versus voltage)

-Action-phase jump analysis for local optics corrections, comparisons to S-b-S

 

actions:

-send email to Georges about disp meas at wires/BSRT -> With tools we get another BPMs for free

-Organize meeting with Jorg and Riccardo for Q3 offset and Totem potential

 

 

##################

Thomas, Barbara,  Fringe 

b6 distribution along MQXF changes correction by ~20%. Is this effect also in LHC b4? Thomas and Barbara will check, even from rough magnetic models.

Beta from amp should neglect IR BPMs as we know calibration is not good.

Up to 3% beta-beating for HL-LHC could be expected.

Median absolute Deviation: sigma_mad = 1.4*median( FFT/N - mean(FFT)/N)

FFT is complex, so maybe 1.4*median( FFT/N ) does the same.

Action:-> Send code to Thomas to also compute resolution versus N for Sussix or Harpy. He used NAFF which gave poor phase measurements.

-> MD proposal for LHC injection, LOF/ LOD , MCO or IR  (segment-by-segment should see local sources)

To measure beta versus amplitude a single kick + k-modulation could be used.

 

 

 

 

 

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