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AMS01 Co(s)mic Ions 010708

AMS01 Co(s)mic Ions 010708. AMS - 01 Data: Z>2 statistics. Reruns of Data done in August i) rerun with AntiHe recostruction cuts: high thresholds for Cluster charge (S>30, K>25) and S/N (>6 for S, >5 for K) It has been processed iì) rerun with standard cuts

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AMS01 Co(s)mic Ions 010708

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  1. AMS01 Co(s)mic Ions 010708 E.Fiandrini, N. Tomassetti

  2. AMS-01 Data: Z>2 statistics • Reruns of Data done in August • i) rerun with AntiHe recostruction cuts: • high thresholds for Cluster charge (S>30, K>25) and S/N (>6 for • S, >5 for K) • It has been processed • iì) rerun with standard cuts • To be processed • A total of 232603 (251688 with std cuts) heavy ions have been identified (-7.6%) • harder cuts remove junk clusters (not rec events are all with low charge cl) • MC sample not affected (-1.1%) since there is less junk E.Fiandrini, N. Tomassetti N. Tomassetti Perugia, Marzo 2008

  3. MC Sample ION P range DST's LVL1 Triggers PG Status --------------------------------------------------------------------------------------- Li7 2-250 166 539187 10^8 165/539116 Downloaded Li6 2-250 159 556936 99997589 N/A Queued Be9 2-250 153 458509 100008090 141/412855 Downloaded Be10 2-250 174 497303 105635216 N/A Queued Be7 2-250 160 483564 100008888 N/A Queued B11 2-250 126 392723 99999855 126/392723 Downloaded B10 2-250 174 497303 105635216 Downloaded B11 2-50 129 408465 102400101 Downloaded C12 2-250 128 345777 10^8 127/342453 Downloaded C12 2-250 35 159261 26913909 N/A Queued C12 2-50 217 721836 201635145 Downloaded N14 2-250 250 628780 200147195 250/628780 Downloaded O16 2-250 251 554142 200007225 251/554142 Downloaded Total Statistics 2527616 E.Fiandrini, N. Tomassetti

  4. MC •  MC is generated • Isotropic in solid angle and, • Uniform in logP From the top plane of a L= 3.9 m cube Generation acceptance is A0 =  L2 = 47.78 m2sr K is given by the condition E.Fiandrini, N. Tomassetti

  5. Selection analysis • Event cuts: • Paddle 10 in Plane 3 of TOF cannot be used for TOF • Inefficient reconstruction of tracker K side (FalseTOFX) • Track fit quality (2fast, 2NoMS) • Tracker Rec Pattern •  – Rigidity Match • Ratios of Rigidity to Half Rigidities, R1/R, R2/R • Closest distance between track extrapol and hits in missing planes • Closest distance between track hit and hits in same layer • NO cuts dependent on cluster properties Quality E.Fiandrini, N. Tomassetti

  6. Data MC Data R<0 MC R<0 Bad TOF+FalseTOFX MC's have not False TOFX Only »3% of DATA is affected Only LVL3 + Part>0 is applied MC have correct fraction, Data appear to be not triggered or rec E.Fiandrini, N. Tomassetti

  7. Track Fit Quality • Fast non linear fit used four times in the following modes: • In the default algorithm, all hits are used to determine the track parameters, R and fast • The same algorithm is applied to the 1st and 2nd half of the track, evaluating R1 and R2 • Multiple scattering is neglected in a 4th iteration which yields diffrenet results especially in the low rigidity region. The resulting parameters are RnoMS and MS E.Fiandrini, N. Tomassetti

  8. Quality Cuts: 2NoMS MC Data Large at low rig due to Coulomb Scatt (it worsens since CS is not taken into account) Important at low R B C E.Fiandrini, N. Tomassetti

  9. Quality Cuts:2fast MC Data Increase at low rig due to tracker ineffic., misalignment, noise, -rays production B C E.Fiandrini, N. Tomassetti

  10. –R match MC Data Well measured events lie around the curve B Mismeasured events cluster at low R and 1/» 1 C Blue lines describe the applied cuts E.Fiandrini, N. Tomassetti

  11. Half Rigidities MC Data To reject events which underwent to important nuclear scattering R/R1 and R/R2 are used B Loose cut on R/R1 0<R/R1<2 Tighter cut on R/R2 0.<R/R2<2 to take into account the MS integrated effect along the trajectory path C E.Fiandrini, N. Tomassetti

  12. Half Rigidities MC Data To reject events which underwent to important nuclear scattering R/R1 and R/R2 are used B Loose cut on R/R1 0<R/R1<2 Tighter cut on R/R2 0.<R/R2<2 to take into account the MS integrated effect along the trajectory path C E.Fiandrini, N. Tomassetti

  13. First 1 2 3 4 5 Last 6 Span = Last Layer Used– First Layer Used E.Fiandrini, N. Tomassetti

  14. Track Pattern Track Patt = 21 seems to be preferred for R<0 events Hard Cut! NB: No wrong sign rigidity when using 6 hits tracks E.Fiandrini, N. Tomassetti

  15. 1 2 3 4 5 6 If the number of consecutive planes is small, it is possible that an interaction (eg large angle MS) in between 2 hit planes is overlooked E.Fiandrini, N. Tomassetti

  16. Missing plane frac E.Fiandrini, N. Tomassetti

  17. Missing Planes No cluster activity requested in § 5cm from track extrapolation position in missing plane Rigidity meas may be overlooked with hits in missing planes close to the track hit E.Fiandrini, N. Tomassetti

  18. Missing Planes: Closest Hit Q Some of the closest hits are particle hits missed by track finding Most are <500 adc but well above the threshold E.Fiandrini, N. Tomassetti

  19. Close hit fraction E.Fiandrini, N. Tomassetti

  20. Hits close to track hits Some track hits have close clusters (merging included) Likely due to collinear -ray emission No clusters within § 200 channels (§ 2.8 cm) from track hits E.Fiandrini, N. Tomassetti

  21. Cluster Quality for Charge Id New charge id algorithm by Nicola used to identify the ions charge Apply some quality cuts on single hits to remove bad clusters Likelihood built with the three hits which maximize it Charge not identified in events left with less than three hits 9% of events have not charge id BUT... They are all removed by the event selectionin the final sample all events have charge id E.Fiandrini, N. Tomassetti

  22. Occupancy Relative Occupancy Fraction = (Channel Hits)/(Average Ladder Channel Hits) An Y channel is declared DEAD if ROF<0.4 (10.5 %) An Y cahnnel is declared HOT if ROF>2 (1.6 %) An X channel is declared DEAD if ROF<0.61 (17.5%) An X cahnnel is declared HOT if ROF>2 (1%) Well described by a gaussian with peak @1 and ¼ 0.2 E.Fiandrini, N. Tomassetti

  23. Occupancy • A cluster is declared BAD if: • It contains a hot strip • It contains or is adjacent to a dead strip • it is within 1 channel length from edges E.Fiandrini, N. Tomassetti

  24. D Seed 1 Seed 2 First Clus Chan: Seed -2 Last Clus Chan: Seed +2 Distance between track cluster and cluster on same ladder A fraction of track clusters have another cluster attached or within few channel lenghts Max Clus Length is 5: Seed § 2 channels If real cluster length exceeds 5, two adjacent cluster are created  need to re-clusterize E.Fiandrini, N. Tomassetti

  25. Adj Cl Trk Cl Adj Cl Trk Cl Re-Clusterization Re-cluster only if Q fraction>10% to avoid noise Last Clus Chan: Seed +2 First Clus Chan: Seed -2 A tail after re-cluster E.Fiandrini, N. Tomassetti

  26. Cluster Length Data Cluster Length >2 Most of clusters have length >3 With (mostly not fully relatistic) heavy ions with inclined trajectories is unlikely to have "short" clusters due to high charge deposit  Lengths <3 are indicative that a cluster which is the "tail" of a larger cluster was used in track fitting E.Fiandrini, N. Tomassetti

  27. Nclose = 0 A close cluster is a cluster separated by at least 1 channel and within Nmax channels from track cluster with NmaxY = 20 (§ 2 mm) Nmaxx = 10 (§ 2 mm) E.Fiandrini, N. Tomassetti

  28. Seed 2nd Max Seed 2nd Max Good cluster Bad cluster Cluster morphology | # Seed – # 2nd Max| · 1 Indication either of channel inefficiency (but not dead) or a possible -ray emission or nuclear fragmentation E.Fiandrini, N. Tomassetti

  29. Cluster quality Quality dominated by dead/hot channels (occupancy) »20% of clusters removed E.Fiandrini, N. Tomassetti

  30. Acceptances 11B Npart>0 LVL1 BadTof+FalseTOFX 2fast 2noms -R match LVL3 0<Ri/R<2, i=1,2 Track Patt Missing planes Npart>0 Hit close to track Selection E.Fiandrini, N. Tomassetti

  31. Acceptances 12C Npart>0 LVL1 BadTof+FalseTOFX 2fast 2noms -R match LVL3 0<Ri/R<2, i=1,2 Track Patt Missing planes Npart>0 Hit close to track Selection E.Fiandrini, N. Tomassetti

  32. E.Fiandrini, N. Tomassetti

  33. Final sample C Some R<0 events pass the selection B E.Fiandrini, N. Tomassetti

  34. B/C ratio (Rigidity) No ratio below 1.1 GV because of acceptance E.Fiandrini, N. Tomassetti

  35. B/C ratio (Ekin/nucl.) Acceptance is vs. True Ekin C B Data are vs. Meas. Ekin Deconvolution needed E.Fiandrini, N. Tomassetti

  36. Deconvolution Unfolding to be done E.Fiandrini, N. Tomassetti

  37. B/C ratio (Ekin/nucl.) C B E.Fiandrini, N. Tomassetti

  38. B/C ratio (Ekin/nucl.) E.Fiandrini, N. Tomassetti

  39. B/C ratio B: secondary C: primary Supernova accel: -2.0 Residence time: tesc-0.7  Estimation of cr in the galaxy E.Fiandrini, N. Tomassetti

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