Difference between revisions of "UITF Notes"

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== For future study ==
 
== For future study ==
 
* Provided the BPMs work at all, we can use the 701 and 702 BPMs to better measure the momentum jitter. The CW waveforms give time-domain data in 900-microsecond-long windows with 16384 samples each, i.e., ~ 18 kHz sampling rate, 9 kHz analog bandwidth. More than enough to see all peaks, maybe even a little much to resolve them well. The only problem is, we can only run 100 nanoamps CW into that line. See if that's enough to see anything.
 
* Provided the BPMs work at all, we can use the 701 and 702 BPMs to better measure the momentum jitter. The CW waveforms give time-domain data in 900-microsecond-long windows with 16384 samples each, i.e., ~ 18 kHz sampling rate, 9 kHz analog bandwidth. More than enough to see all peaks, maybe even a little much to resolve them well. The only problem is, we can only run 100 nanoamps CW into that line. See if that's enough to see anything.
 +
* Try to measure dp/p as a function of buncher GSET with 7-cell off, assuming the slow beam can be focused well enough. For 20 or 30 ps bunches, it should be 7e-4 or 10e-4, respectively.
 +
* If there is time, also measure it as a function of 2-cell phase.
  
 
== Take home ==
 
== Take home ==
 
* Re-survey 700-line element positions
 
* Re-survey 700-line element positions
 
* Corrector CST model
 
* Corrector CST model

Revision as of 20:36, 6 December 2021

Random

  • Harp axis calibration does not matter: It only changes the measured emittance but not alpha/beta, and its effect does not depend on the quad in use.
  • Adding reasonable quadrupole moments to correctors is not enough to explain the inconsistency. It would need an extra quad with K1 ~ 5.
  • At dp/p = 1e-3 (which is higher than what we observe unless the measurement is flawed), seeing significant inconsistencies in the quad scans needs a dispersion of many cm. In y, the only dispersion in this part of the lattice should come from the earth's field; this gives about 8 mm at the harp, much too low to see anything.

For future study

  • Provided the BPMs work at all, we can use the 701 and 702 BPMs to better measure the momentum jitter. The CW waveforms give time-domain data in 900-microsecond-long windows with 16384 samples each, i.e., ~ 18 kHz sampling rate, 9 kHz analog bandwidth. More than enough to see all peaks, maybe even a little much to resolve them well. The only problem is, we can only run 100 nanoamps CW into that line. See if that's enough to see anything.
  • Try to measure dp/p as a function of buncher GSET with 7-cell off, assuming the slow beam can be focused well enough. For 20 or 30 ps bunches, it should be 7e-4 or 10e-4, respectively.
  • If there is time, also measure it as a function of 2-cell phase.

Take home

  • Re-survey 700-line element positions
  • Corrector CST model