Difference between revisions of "UITF Notes"
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== MeV beam time == | == MeV beam time == | ||
| − | * Measure MeV dispersion with BPMs | + | * Measure MeV dispersion with BPMs => Done, need to analyze |
* TM beam to 703 to see RF drift (full shift) | * TM beam to 703 to see RF drift (full shift) | ||
* Verify optics setup for HKDL | * Verify optics setup for HKDL | ||
| − | * | + | * Repeat buncher study, booster crested, 8 MeV, multiple scans per point |
| − | + | * Still need to look at the [https://logbooks.jlab.org/entry/4019436 dispersion results] | |
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== keV beam time == | == keV beam time == | ||
| − | * LVQE scan at different voltages. Expect same result. | + | * LVQE scan at different voltages. Expect same result, provided different laser powers at same voltage give same result (avoid SCL). |
| + | ** Results are different, don't know if related to instrumentation (battery resistance etc.) or physics. If it's physics: | ||
| + | *** CST: Does thermal energy affect collection efficiency? | ||
| + | *** Ion current? probably too low to matter | ||
| + | *** Try adjustable bias voltage source (Keithley) | ||
* HVQE scan at different voltages. Expect different result. | * HVQE scan at different voltages. Expect different result. | ||
| − | |||
* High current to FC2 for 12+ hours, check if drift is gone | * High current to FC2 for 12+ hours, check if drift is gone | ||
| + | * Look at [https://logbooks.jlab.org/entry/4022870 mains-harmonic BPM signals] as a function of parameters (buncher etc.) | ||
== Beam line modifications == | == Beam line modifications == | ||
* Put HKDL stuff into the machine ahead of time! | * Put HKDL stuff into the machine ahead of time! | ||
| + | * Fix [https://logbooks.jlab.org/entry/4019472 miswired MeV correctors] | ||
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| + | == Random things to change when it makes sense == | ||
| + | |||
| + | * The way MFQK403 is supposed to focus into both Aperture A4 and the booster is flawed for multiple reasons: | ||
| + | ** The lens would need to produce multiple waists (DP can, A4, Brock cavity, RM11), so the focal length is a compromise. But interestingly, it is the same at CEBAF. | ||
| + | ** The orbit needs to be very straight for the beam to make it all the way downstream, but to adjust this, we need both upstream correctors, 401A and 402, so centering in the lens at the same time is very difficult. | ||
| + | ** We should do a GPT study and play with a potential extra lens, but I would intuitively suggest something like this: | ||
| + | *** Remove Brock cavity, not needed | ||
| + | *** Add corrector between MFQK403 and A4 | ||
| + | *** I think having the beam converge slowly into the booster is good, so I like that the lens is far away. Maybe the aperture should just be closer to the booster? At the very least, put it behind the BPM so we can see where we're at. | ||
| + | * MFAK303 has a similar problem. Being single-wound, it is supposed to be equal and opposite to MFAK301, but this fixes its focal length, while it is supposed to focus in both the buncher and the dipole. This issue does not seem critical, but it could be pondered sometime. | ||
Revision as of 11:39, 20 August 2022
MeV beam time
- Measure MeV dispersion with BPMs => Done, need to analyze
- TM beam to 703 to see RF drift (full shift)
- Verify optics setup for HKDL
- Repeat buncher study, booster crested, 8 MeV, multiple scans per point
- Still need to look at the dispersion results
keV beam time
- LVQE scan at different voltages. Expect same result, provided different laser powers at same voltage give same result (avoid SCL).
- Results are different, don't know if related to instrumentation (battery resistance etc.) or physics. If it's physics:
- CST: Does thermal energy affect collection efficiency?
- Ion current? probably too low to matter
- Try adjustable bias voltage source (Keithley)
- Results are different, don't know if related to instrumentation (battery resistance etc.) or physics. If it's physics:
- HVQE scan at different voltages. Expect different result.
- High current to FC2 for 12+ hours, check if drift is gone
- Look at mains-harmonic BPM signals as a function of parameters (buncher etc.)
Beam line modifications
- Put HKDL stuff into the machine ahead of time!
- Fix miswired MeV correctors
Random things to change when it makes sense
- The way MFQK403 is supposed to focus into both Aperture A4 and the booster is flawed for multiple reasons:
- The lens would need to produce multiple waists (DP can, A4, Brock cavity, RM11), so the focal length is a compromise. But interestingly, it is the same at CEBAF.
- The orbit needs to be very straight for the beam to make it all the way downstream, but to adjust this, we need both upstream correctors, 401A and 402, so centering in the lens at the same time is very difficult.
- We should do a GPT study and play with a potential extra lens, but I would intuitively suggest something like this:
- Remove Brock cavity, not needed
- Add corrector between MFQK403 and A4
- I think having the beam converge slowly into the booster is good, so I like that the lens is far away. Maybe the aperture should just be closer to the booster? At the very least, put it behind the BPM so we can see where we're at.
- MFAK303 has a similar problem. Being single-wound, it is supposed to be equal and opposite to MFAK301, but this fixes its focal length, while it is supposed to focus in both the buncher and the dipole. This issue does not seem critical, but it could be pondered sometime.