1. 1 Downstream PID performance MICE analysis phone conference 2007-01-08 Rikard Sandström

2. 2 Outline Test of fitting methods –ANN, Fisher and LikelihoodD Intrinsic purity –Unmatched beam, flip mode Reminder of old performance New performance Details –New and modified variables –Redefinition of good events PID and emittance Conclusions

3. 3 Test of fitting methods (140 MeV/c)

4. 4 Choosing variables For now all variables which have proven useful in the past are used. Due to the good performance a set of exclusively calorimeter dependent variables have also been tested. Which variables are ideal depends on beam momentum. –Hardest case is low momentum, so most of the effort has gone into finding useful variables at 140 MeV/c. Variables are ranked depending on –Separation  ½ ∫ (s(x)-b(x)) 2 / (s(x)+b(x)) dx –Background rejected at 99.9% signal efficiency. –Correlation with other variables

5. 5 Stage 6 - purity In stage 6, objective is to measure emittance to high precision. –Requires high purity from background. Requirement: –Signal efficiency = 99.90%. –Purity = 99.80%. Safety margin: –3 times expected background. At non flip magnetic field mode, expect much more background since fewer background tracks lost at absorbers. –Safety margin can be expressed as purity = 99.93% Initial mom [MeV/c] Input purity Req. BG rej. (purity 99.80%) Safety BG rej. (purity 99.93%) 14099.56>54.2>84.5 17099.59>51.6>83.9 20099.63>46.5>81.3 24099.63>46.4>81.3 Not meeting req.Meeting basic req.Meeting safety req.

6. 6 Results – Stage 6, summary BG rejection Initial mom. No cal., with TOF KL, no TOF SW, no TOF KL, with TOF SW, with TOF 140±14 MeV/c 47.8%56.2%79.5%58.2%79.5% 170±17 MeV/c 54.1%48.8%56.4%59.0%67.8% 200±20 MeV/c 59.0%57.3%74.2%79.4%87.6% 240±24 MeV/c 64.5%65.0%91.4%80.0%92.2% TURTLE 83.5% Not meeting req.Meeting basic req.Meeting safety req.

7. 7 Results – Stage 6, summary BG rejection Initial mom.SW, only EMCalSW, with TOFs & SciFi 140±14 MeV/c 77.6%89.0% 170±17MeV/c 88.0%98.4% 200±20MeV/c 97.9%99.0% 240±24MeV/c 97.2%99.5% Not meeting req.Meeting basic req.Meeting safety req.

8. 8 Results – Stage 6, safety factor Initial mom.SW, only EMCalSW, with TOFs & SciFi 140±14 MeV/c 2.04.1 170±17MeV/c 7.731.1 200±20MeV/c 25.056.3 240±24MeV/c 19.2101.5 Not meeting req.Meeting basic req.Meeting safety req.

9. 9 ANN output, 240 MeV/c

10. 10 ANN output, 140 MeV/c

11. 11 Efficiencies, 140 MeV/c

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27. 27 Redefinition of good events I addition to all previous requirements (inside trackers, momentum and tof reasonable etc) a hit in the calorimeter during the open gate was added to the list.

28. 28 PID and emittance Together with Chris we have developed a way to look at bias on emittance due to mistaken pid. –That will be another talk/MICE note by either of us. Calorimeter specific variables are now reconstructed in the Reconstruction application, just like trackers and tofs. –Cross detector variables are still handled in a custom made application called RootEvent. –Tracker and TOF values are still smeared MC truth, but using real reconstructed values will be easy.

29. 29 Conclusions All requirements in terms of purity and efficiency are fulfilled. –Calorimeter is close to fulfilling safety requirements (green) completely on its own, making it The PID detector. Performance is excellent for high momentum, and worse but still good for low momentum. No single variable is good enough on its own ->  Multi variable analysis, best handled with Artificial Neural Networks. Cases not (re-)studied: –Stage 1, muon-pion separation. –Stage 6, non flip mode Higher background transmission? Worst case scenario is likely 140 MeV/c non flip mode.