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Description
Ryan showing his work getting madx running
- Q: Super tiny beta functions ~3-4cm + very strong magnets (~20T). Can MadX actually handle situations like that → Eliana thinks yes
- Q: Does madX care about energy? → no but if you want to compute synchrotron radiation then you must specify the particle/energy
- Eliana will send tips on an easier way to specify drift lengths
- describe beam line this is inconvenient (have to compute drift by yourself). with bending magnet you must specify bending magnet lengths and cord lengths
- if you don’t specify the drift length (then use a different kind of input, eg. just specify the center of the magnet x position and have madX compute the drift length itself)
- If you have a very periodic structure, the way ryan was doing this might be more helpful, but for us we have a fairly short structure
- Some other aspects of MadX
- Doesn’t do material interactions
- Not good at aperatures/beam pipes
- Discussion on particle tracking in MadX
- PTC - is an old code that does particle tracking, seems to not be reliable/easy to use
- Otherwise you need to use thin structures to do tracking, which doesn’t play nicely with the thick structures (like magnets)
- It’s much easier to do the matching/magnet optimization in MadX, implement magnets with those parameters into G4Beamline, and do particle tracking in G4Beamline
- Input to MadX: betatron functions
- Input to G4Beamline: individual particles in a beam
- Need code to go from one to the other (Daniel mostly has this already)
- → Bigger picture plan for this project
- Go through the first wedge G4beamline w/ particle tracking
- Compute the beta functions & input to MadX
- Perform the matching in MadX (save and check output beta functions)
- Implement/update magnets in G4beamline
- Perform particle tracking through magnets & second wedge in G4beamline (compute & cross check output beta functions w/ MadX)
- (Sounds like learning about MadX python bindings might be useful for automatic all of this)
- Ryan next steps for 1-2 weeks:
- Try a matching situation (large beta → small beta or the reverse)
- Go through a drift (put magnets at locations downstream) / vary strength of magnets until you get a match of the betatron functions
- Once you’ve done the optimization in MadX, implement the solution in G4beamline
- For a given beta function, create corresponding beam
- Implement the magnets in G4beamline & pass the beam through the magnets
- Run particle tracking & compute resulting beta distributions
- Make sure beta distributions correspond to what you found with MadX
- Things to keep in mind (how quads are specified, signs, normalized/unnormalized beta distributions)
Additional discussion
- Why can’t you use electrons/protons to test ionization cooling?
- protons you have nuclear interactions (depending on energy is it closer → low momentum protons because some nuclear interactions are reduced. but then not relativistic)
- electrons you have brem/electrons stopped in materials
- 200 MeV muons ~ 10 MeV protons
- Things you could test with protons - intensity effects/break down in RF cavities
- breakdown in RF cavities was studied at MTA at fermilab
- adding a beryllium coating reduced breakdown
- cause of breakdown is dE/dx, energy results in damage to the material of the cavity
- wanted to test aluminum and diamond windows becuase they also have low Z, and are easier to manufacture
- Lecture notes also include a section on dispersion suppression, keep this handy
IPAC
- deadline for conference paper is next wednesday, david will send another draft
- poster presentation is may 21st (tuesday)
Plans for the summer
- Daniel
- will work in 3DL - intersection of 3D and Deep Learning this summer
- will be remote (in virginia and then china) until the beginning of July
- interested in following this project as much as he can
- Ryan
- received the quad fellowship to support him this summer
- will start Jun 17th
- Setup a day to visit Fermilab so Ryan can meet everyone in person
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