Status report - Tracking code - T.Gogami 9/30/2010

Content Debug – test point – drift time Simulation for tracking efficiency e,e + background

Test point calculation in pattern recognition for HKS y-coordinate sign is opposite ! Test point coordinate ( x, y ) But in current code There is no affection to select space points. But this affect in “h_tof_pre.f”. (this case is so rare)

Clusters in residual vs. χ 2 distribution x [cm] x’ [rad] Single residual (KDC1-3) [cm] Track χ 2 Drift time [ns] Longer drift time events make clusters

h_tof_pre.f pre track with space points – single hit in KTOF – multi hit in KTOF start time calculation for drift time of chambers correction (card)

Bugs in h_tof_pre.f start time for drift time KTOF TDC information – single hit – multi hit (mean)

Residual vs. χ 2 CH 2 target Current New Current New CH 2 target 16 % for 52 Cr target 40 % Disappear clusters

Drift distance x’ vs. residual x’ reference plane Residual [cm] (KDC1-3) x’ reference plane Residual [cm] (KDC1-3) drift distance [cm] Current New Current Stripe CH 2 target

52 Cr target Need to improve tracking code K+K+ KDC1 KDC2 KTOF1X Now developing Current analyzer cannot handle with high multiplicity data 1.input tracks in simulation ==> output file (hit wire info and so on) 2.input this file to real analyzer 3.see output tracks and compare to input tracks Simulation for HKS tracking efficiency (by D.Doi) one result of this simulation

e,e + b.g. in HKS TOP view Side view X [cm] X’ [rad] 5 × 5 [cm 2 ] HKS - D HKS - Q

B.G mix rate in HKS trigger just after pattern recognition ==>cut bad combination of space point (like h_tof_pre) ==> Saving CPU power, Reduce analysis time 52 Cr (77124) 12 C (76077) 9 Be (76607) 10 B (76184) 7 Li (76184). ×10 44 a b B.G. mix rate = a/(a+b) Developing B.G. cut routine

Multiplicity in chambers CH 2 target 52 Cr target mean ~ 6 hit mean ~ 2 hit CH 2 target 52 Cr target mean ~ 1 hit 10 6 layer 6 6 HES HKS Origin of high multiplicity is ee + B.G. ? after TDC cut ~2 [MHz] (8 [μA] on 52 Cr) ~18 [kHz] (8 [μA] on 52 Cr)

Summary and to do Summary – debug test point calculation in “find space point” – opposite sign for y-coordinate of test point ( finalminnum --> finalminnum+1 ) in “h_tof_pre.f” – drift time distribution got better – entry number is up (CH 2 :16% up, 52 Cr:40% up) – Simulation for HKS tracking efficiency by D.Doi – e,e + B.G mix rate is high especially for 52 Cr target. – need to cut before tracking Origin of high multiplicity ? to do – Development reject e,e + B.G routine choose single hit routine --> see all combination – Check HES side tracking code e,e + B.G origin ? – check ADC – Simulation

Generated e + in Simulation p e+ : 1.2±0.5 [GeV/c] θ : 0.124±0.124 [rad] φ : ±0.5 [rad] target : 12 C 100[mg/cm 2 ] HKS D magnet Splitter magnet beam: spherical uniform generation no collimator EM flag on