Brief summary of meeting
Attendance: Tony, Marius, Sasha, Maryna, Jenny, Beate
1) Sasha's talk:
- p2: Seems that the asymmetry in the y-plane between electrons and positrons is due to secondary electrons/positrons with laser photons. Two actions:
- A1: Tony to generate MC with head-on laser beam, and to check orientation of the curreny 17-degree laser (horizontal or vertical?)
- A2: Sasha to check if in stdhep file the asymmetry is indeed there for "final" electrons and positrons
- general: action A0 is to agree on naming of the various regions of our experiment (either A, B, C... or something else) (Sasha and Marius)
- p6: either make clear that this talk is only about gamma-gamma or add rates for the egamma setup also (that would be best!)
- p7: also mention XFEL beam parameters
- p9: explain what "selections" are in green curve in top plot: is this the x/y selection of 25 um?
- p13: remove 2m option
- p14: update slide significantly: remove "collimator" and "dipole" rates but add rates of "detectable" el. and pos., i.e. energies between 1 and 16 GeV. Also, add rate of electrons/positrons at G assuming wire. And, label plot clearly with regions "A, B, C..."
- Conclude on rates being order 1M for first region, order 100 for 2nd and order 1000 for third region of e+e- detectors => propose silicon+cerenkov+calorimeter for the 2nd and 3rd, and cerenkov+calo for the first?
- p15: give rates for two example values of intensity (low and high). Also, add positron and electron rates (E<16 GeV).
2) Marius talk:
- Make clear in title which e+e- system is being discussed (see naming issue action)
- p3: photon detection => forward detection, remove distances here
- p4: add cerenkov as option
- somewhere before page 6 explain MC and show a few more distributions, e.g. xi distribution, time distribution, energy distribution for two values of intensity.
- p6: keep rate plots to last, first show the more basic distributions.
- p8: rename to say "occupancy vs detector granularity". Many other detailed comments on exact wording, not repeated here now. Would be also nice to order the table by grnularity from coarse to fine or so.
- p9: use table instead of plots. Draw conclusion that granularity \lsim 1mm is ~OK => Calorimeter also interesting also since energy will also tell us if one or two particles hit it as position also tells us energy.
- p10: add ALICE as example.
- p11: add that we still want to study impact of laser pulse shape
3) Maryyna's talk:
- add page numbers
- try to improve "story line", i.e. make sure it is clear that main problem comes from finite width of laser pulse intensity distribution => very hard to see compton edge even at "truth level". Additional issue is that HUGE fluxes, hard to measure energy of individual particles.
- p3: use e+gamma here instead for plot
- p11: simplify and make more pedagogical. Show plot of xi distribution for high- and low- intensity examples. Show large tail, use this to explain effect on photon energy spectum => smears out edge.
- p13: remind people that we want to a) measure number of photons and b) measure energy spectrum
- p18: reconsider 2nd bullet! Maybe add something on photons from gamma-gamma process? (Wire seems good idea for that too)
Actions:
- A0: agree on naming of individual parts of experiment (Sasha, Marius)
- A1: produce MC with head-on laser beam (Tony)
- A2: check if asymmetry appears in sdthep file with final particles (Sasha)
- A3: produce MC with laser pulse following rectangular intensity distribution (Tony)
- A4: produce MC keeping all photons in stdhep file, regardless of whether or not they interacted (Tony)
- A5: figure out how to determine interaction probability vs xi in MC files (Sasha, Marius)
- A6: consider if counting electrons after IP could be easier than counting photons for Compton process (Maryna)
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