Attendees: J. Bauche, F. Velotti, R. Ramjiawan, G. Le Godec, M. Krupa, S. Mazzoni, E. Gschwendtner

• Francesco introduced the HW specification as direct translation of the experiment requirements
• The experiment requested: 
  • < 13 µm offset between electron and proton beam at injection in the second plasma cell
  • < 20% error on beam size for the high energy electron beam at injection
• These 2 requirements are the most constraining. 
• Using these requirements, Rebecca and Francesco produced HW specifications to comply with this
• The summary is:
  • Proton line:
    • x10 ripple/shot-to-shot stability improvement on all TT40/TT41 power converter and MSE4 (SPS extraction septum in LSS4)
  • High energy electron line (new line):
    • New magnets characteristics specified (see slides)
    • For now no indication of field homogeneity - Francesco to organise follow up with Jeremie
    • BPM resolution < 1 µm needed to have ~6.6% of electron beam with compliant beam size at injection
    • BPM accuracy still to be fully investigated to be followed up with Stefano and Michal
    • BTV position accuracy will be crucial, but also there more studies needed
    • PC ripples are constrained by errors on beam size at the injection point
    • To satisfy experiments requirements needed ripple/shot-to-shot variation < 7 ppm (rms)
• A discussion followed on the different points:
  • Magnets:
    • Jeremie commented that from a quick first look, the specifications do not seem impossible, but still to be confirmed: Jeremie to comment further on this after initial investigation
    • Also, Jeremie proposed to see if we could use permanent magnets to improve stability. Gilles commented that the usage of PC in DC with very high current should be checked in details.
  • Beam instrumentation:
    • Michal commented that 1 µm resolution with BPM, with the required aperture would require a significant R&D effort, and of course to be seen if feasible at all
    • This is about 10 times better than the present electron line
    • Specifications also more challenging than CLIC (small chambers there). 
    • BPM accuracy is closely related to BTV position accuracy, as the BTV will be the device that surely can resolve both proton and electron beam
    • To follow up together on BTV and BPM accuracy: Rebecca and Francesco to get in touch with BI guys for followup
  • Power converters:
    • Gilles commented that the x10 improvement required on the MSE4 and all TT40/TT41 converters to satisfy the experiment requirements is impossible
    • New PC would be needed to achieve this - this can be a project by itself and it will be very expensive
    • Edda to report to experiment and discuss possible strategy
    • For the new electron line, to be seen what can be done - first need current specifications: Jeremie to provide first estimation on current range based on magnets specs
• Francesco and Rebecca agreed in reporting this to the AWAKE Technical Board.