Connected: Andrei, Anna, Vasilisa, Eduard, Mitesh, Melvin, Lesya, Anne-Marie

Three areas for Feb19th meeting

background and shield optimisation:
- - optimisation ongoing (presented at Physics meeting this morning) concentrates only on muons from target.
  - want to add study of EM showers and other possible backgrounds coming from last muon shield magnet, including also muon and neutrino DIS giving hadronic showers.
  - Melvin is studying an additional layer to deflect background with low momentum charged tracks, will prepare a drawing to explicit his idea, which is also connected to the installation and access of SND inside the muon shield.
  - Any material added may be again source of bkg to be studied...
  - Eduard presented a study of the particles found inside SBT, and where they come from.
  - Several questions asked: * are the photons coming from mu brem? * check whether the particles from the subsequent material are due to the ones emitted from the last magnet * should we worry about neutrons ? * asymmetry between protons/antiprotons, e+ and e-, is it understood? More generally can we check if rates are ball park of what we expect ?
SND optimisation and integration:
- - discussion about the non-uniformity of SND and impact on B field from muon shield.
  - constraints from integration: space available if from above, or access pit in larger part of the cavern, requirement would be to be accessible once installed.
  - discussion on best place: 1st magnet of the last 3, or last one: background from muons is not an issue, so integration is the main problem. Melvin to provide a drawing of his idea for this as said above.
  - optimisation of absorber thickness wrt backgrounds and B field.
  - for sensitive layers, the total dose expected will drive the need for cooling, and should be the first thing studied.
  - discussion on value of B field, assuming 1.7 T but cannot really go lower if we want to keep the required momentum resolution for tau-neutrino reco.
UBT as last layer of SND