Responses to Kiyoshis Questions:

1

• Responses to Kiyoshis Questions
• 1) Slide 12 Need to perform 2D scan in y,y
  space to find optimal collision parameters, 2 1D
  scans doesnt
• give best performance.
• How bad are the 2 1D scans? Is it correct that
  you had shown good single-seed result with 1D
  scan?
• Keeping everything the same other than the
  optimisation method- with the 2 1D scans, I get a
  mean lumi of 86 with a 1 sigma spread of 2.5
  with the 2D scan, I get the 93 /- 1 that I
  showed.
• 2) Slide 14 What are the definitions of Lplat,
  Lmax and L?
• How long cpu time was needed for the results?
• Lplat is the mean luminosity of the last 50
  bunches in the simulated part of the train (the
  flat part).
• Lmax is the mean luminosity of a line touching
  the top of the envelope of points of the last 50
  bunches (estimate of removing bunch-bunch random
  jitter effects).
• L is the calculated luminosity- ie. If N is the
  number of simulated bunches, and l is the
  luminosity of each bunch- LSUM(l(N))SUM(l(N-50N
  ))(2820-N)/N
• The simulations take 30-40 hours per seed (the
  number of bunches actually simulated varies as
  the convergence time of the optimisation depends
  on how close to the optimum you start for that
  seed.
• 3) Last slide I do not understand your
  calculation.
• 10 mins per single bunch track, 30 hours per
  multi-bunch simulation
• Do you have 180 bunches? Why? If 2800 bunches,
  why 10 mins and 30 hours?
• If choose N once per day and Mevery 30 mins
  and want 100 seeds, this is 475 days of cpu
  time!
• How many single bunch and how many multibunch
  trackings? Why?
• As mentioned above, number of bunches varies
  seed-seed, but typically lt500 needed.
• 10 mins per single bunch assumed if only needing
  to track and operate feedback algorithms, no
  beam-beam simulation, only do this on
  multi-bunch, which assume takes same amount of
  time as what I have done for FFB studies. This is
  all probably optimistic!
• I chose time periods as an example, can of course
  change these