AWAKE Run 2bc Spectrometer

Wednesday 9 Apr 2025, 13:30 → 14:30 Europe/Zurich

CERN

Present: Matthew Wing, Nikita Zena van Gils, Marlene Turner, Collette Pakuza, Edda Gschwendtner, David Cooke, Joe Wolfenden, Fern Pannell, Patric Muggli

Follow-up:

• Before the start of the next run: ensure that the spectrometer is working.
  • To do: DC, FP Ensure that the spectrometer GUIs can be started.
  • To do: FP suggested changing some of the spectrometer cameras → recalibrate for stitching.
    
    
• Cabling:
  • MT submitted the DC cabling request for the Run 2c spectrometer, assuming three quads and a dipole, and requested an additional 13m of cable at the magnet end to allow for a potential downstream move of the magnets for Run 2d.
  • Spectrometer magnets are very heavy; moving them for Run 2d is challenging.
    • No issue for the Run 2c installation, as long as the magnets are installed first.
  • Options for moving the magnets for Run 2d are all challenging:

• • • Remove both electron beamlines to allow magnet transport carriers to pass.

    • Place the magnets on rails → expensive, on the order of a few hundred kCHF. To do: MT to ask the transport team for a more accurate cost estimate.

• • Alternative options:

    • Investigate the use of smaller and more magnets with the same power converters.
      To do: MT to reach out to Philip Schwarz.

  • Investigate optics design trade-offs. To do: DC
    
    

• Emittance analysis from last year:
  Scattering in the foil and the plasma ramp effects are both visible effects on the emittance, and for this beam energy (400 MeV), the two effects are comparable.
  At higher energies, the situation will be different: scattering should decrease with energy and spot size (emittance), and the effect of the plasma ramp should also reduce with energy.
  Suggestion: Try to obtain a high-charge dataset at ~1.2 GeV.
  To do: propose 4e14 for the upcoming measurements.
  
  
• Technical specifications:
  • To do: DC to summarize the design in a document.
    
    
• MT presented the current integration drawing.
  • To do: UCL team to confirm the correct positioning of the magnets in the drawing.
    
    
• OSR:
  To do: Liverpool team to investigate the feasibility of diagnostics with the beam parameters provided by DC.
  To do: Liverpool team to identify the best location for the diagnostic (on-axis, off-axis), considering the proton beam halo and the loss of energy resolution on the spectrometer.
  
  
• DC simulated background from the proton beam halo, based on an approximate beam distribution.
  Secondary particles bending in the dipole field will also cause OSR.
  Next step: use the real proton beam halo from simulations.
  To do: DC to implement this based on simulation results from Arthur Clairembaud.
  To do: DC to determine if particles already interact with the quadrupole magnets or only at the dipole magnet.
  
  
• EG to organize a diagnostics review in June, with a tentative date of the 20th of June.
  To do: EG to organize and finalize.

 

13:30 → 13:50 Discussion and Follow up

Speaker: Marlene Turner (CERN)

espec09042025.pdf

13:50 → 14:10 Emittance analysis - measurements

Speaker: David Andrew Cooke (University of London (GB))