Difference between revisions of "UITF Notes"
Jump to navigation
Jump to search
| Line 7: | Line 7: | ||
== 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