1. Optymalizacja SMRD Paweł Przewłocki Warszawska Grupa Neutrinowa

2. Eksperyment T2K (Tokai2Kamioka) Akcelerator, tarcza grafitowa tunel rozpadowy Monitor mionów Stacja ND280 Stacja 2km SuperKamiokande ND280 off-axis N-GRID on-axis  p  140m0m0m 280m 2 km295 km Start: 2009

3. The problem Side Muon Range Detector – measures muon direction and momentum Important for neutrino interactions and cosmic- ray muons (for calibration) We have 15 layers of gaps suitable for scintillator slabs But the number of slabs is limited. Therefore we have to optimize their configuration in order to maximize our measurement capabilities.

4. Nd280 off-axis detector – side view 12345678Rings: 15 layers POD TPC

5. Front view Left lateral part Right lateral part Upper part Bottom part

6. Our ends… Cosmic-ray muon considerations – Piotrek’s presentation My area of interest –measurement of muons from neutrino interactions Muons are mainly measured by TPC – SMRD is important for events that cannot be handled by TPC Question: what is the optimal SMRD layout to measure muons that cannot be seen in TPC?

7. …And means Let’s look at the numbers of the outermost layer reached by muons that are of our interest The tools: Geant4 ND280MC simulation Geant4 ND280MC simulation Input: NEUT files on water (for the time being) Input: NEUT files on water (for the time being)

8. Outermost layer in SMRD 60.000 events from FGD Energy deposition cut – must have at least 0.5MeV to be a valid hit TPC distance cut – muon has to travel maximum 60cm in TPC (longer tracks are reconstructed in TPC and don’t need any additional info from SMRD) „QE” events definition: One muon One muon No pizeros No pizeros No pipluses over 200MeV in energy No pipluses over 200MeV in energy In some cases I split the SMRD into lateral and upper/bottom parts to show the influence of the coil (present only on top and bottom of the basket)

9. Outermost layer distribution 60cm TPC distance cut applied Red – lateral smrd Black – lateral + upper/bottom Lateral parts are more populated All QE Lateral Lateral + upper/bottom Lateral Lateral + upper/bottom

10. Outermost layer - upper vs bottom 60cm TPC distance cut applied Only bottom/upper part of smrd Red – bottom smrd Black – upper+bottom Much more tracks go to the bottom part

11. Some statistics All: Percentages with respect to all mu CC events QE: percentages with respect to all mu CC qe evts Outermost over 4 Outermost over 5 Outermost over 6 all2.94%2.11%1.53% With 60cm TPC distance cut applied 1.97%1.43%1.02% With distance cut applied, only rings #7 and 8 1.6%1.19%0.87% Outermost over 4 Outermost over 5 Outermost over 6 all2.16%1.44%0.94% With 60cm TPC distance cut applied 1.48%1.02%0.67% With distance cut applied, only rings #7 and 8 1.15%0.83%0.55%

12. Conclusions – proposed module distribution Table prepared by Thomas Kutter based on results presented here and some other studies

13. Backup

14. Incoming nu energy distributions Black – all events Red – with 60cm TPC dist cut applied Blue – as above + reaching smrd All QE

15. Incoming nu energy distributions Black – TPC dist cut + reaching smrd Red – at least 4 layers Blue – at least 5 layers Green – at least 6 layers All QE