2017-05-18-optics¶

http://mice.iit.edu/phonebridge.html

• Flip mode runs: MICE_User_Run_2016_05-v4_hack.xls
• Simulated performance - 2016-05: 2017-01-25_2016-05-settings.pdf
• Effect of Al windows on empty channel: 2017-01-25_al-window.pdf
• Post-hoc; quality of match 2017-05-19_2016-05-phase-space.pdf

Intro¶

If

• the lH2 is not ready, and
• the trackers are okay
  we have an opportunity to take more solid absorber data.

I think we have to make a decision, as to whether we:

1. run LiH data; showing emittance evolution with 200 and 240 MeV/c
in flip mode

• we get a few more data points; I note that we have 200 and 240
  MeV/c data in solenoid mode; this would give us comparable data in
  flip mode

2. run empty data; show the difference in performance between empty
absorber and full absorber in flip mode

• we validate the existing data; we can show the difference between absorber in and absorber out, strengthening the existing data set. I guess there is a risk that colleagues tell us "you never checked the 'null hypothesis'"

3. run the wedge

• we potentially get measurements in emittance exchange regime

I would appreciate thoughts. We could have a phone call at 15:00 BST
tomorrow (the usual MICE analysis slot) - this is coincident with the
16:00 coffee break at IPAC.

My feeling is:

- (1) is lower priority. It doesn't really give us much - we have detailed dE/dx measurements and scattering measurements at these momenta, and the performance won't be terribly impressive.
- (2) strengthens our existing dataset; mitigates risk
- (3) is likely to lead to another publication.

Other thoughts?

Notes¶

Jaroslaw
John Nugent
Pavel Snopok

• Jaroslaw
  • it is important for us to run empty absorber; see the change of phase space distribution provided directly by the absorber
  • do we have sufficient data with the solid absorber data that we have a strong cooling signal
  • we could work on improved matching? could improve momentum scale; could improve alpha

• Pavel
  • Preference - try the wedge? Question how much data we can get in the time available?
  • Note absorber changeover is 5-10 days; do we want to try the LiH first?
  • Wedge has never had fit test; but geometry is same as LiH disk; could take longer than LiH
  • One setting is probably all they need; use same magnet settings for emittance exchange and reverse emittance exchange

• Jaroslaw
  • 200 and 240 MeV/c settings would be interesting to finish the momentum scan in flip mode
  • Would prefer to attempt to improve matching and redo data at 140 with LiH
  • Concerned that phase space has a hole in the region of interest
  • Aluminium drowns the effect a bit - significant but not dominant

• Wedge continues to be interesting
• Doing "no absorber" would be a good thing, but probably not the crucial thing; "empty absorber" would be acceptable
• 200 and 240 MeV/c settings not terribly interesting
• Would like to do LiH at 140 MeV/c with better matching
  • Jaroslaw suspects the current matching leaves voids in the phase space

• Need more information:
  • How long to do the absorber changeover?
  • How sensitive is the issue of removing the lH2 absorber?
  • Do we really have holes in the phase space that better matching can address?
    • Post-hoc; effect of 2017-05-19_2016-05-phase-space.pdf ... no