Status report- Tracking code -

T.Gogami9/30/2010

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 !

http://lambda.phys.tohoku.ac.jp/~gogami/HES-HKS/testpoint/testpoint.pdf

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. χ2 distribution

x [cm]

x’ [r

ad]

Single residual (KDC1-3) [cm]

Trac

k χ2

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.fstart time for drift timeKTOF TDC information– single hit– multi hit (mean)

Residual vs. χ2CH2 target

CH2 target

Current

New

Current

New

CH2 target

16 %

for 52Cr target40 %

Disappear clusters

Drift distancex’ vs. residual

x’ [rad] @ reference plane

Resi

dual

[cm

] (KD

C1-3

)

x’ [rad] @ reference plane

Resi

dual

[cm

] (KD

C1-3

)

drift distance [cm]

drift distance [cm]

Current

New New

Current

Stripe

CH2 target

CH2 target

52Cr target Need to improve tracking code

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 HKSTOP view

Side view

X [cm]

X’ [r

ad]

5 × 5 [cm2]

HKS - DHKS - 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

52Cr (77124)

12C (76077)

9Be (76607)10B (76184)7Li (76184) .

×1044

a

b

B.G. mix rate = a/(a+b)

Developing B.G. cut routine

Multiplicity in chambers

CH2 target 52Cr targetmean ~ 6 hitmean ~ 2 hit

CH2 target 52Cr targetmean ~ 1 hitmean ~ 1 hit

106layer

6 layer6

HES

HKS

Origin of high multiplicity is ee+ B.G. ?

after TDC cut

after TDC cut

~2 [MHz](8 [μA] on 52Cr)

~18 [kHz](8 [μA] on 52Cr)

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 (CH2:16% up , 52Cr:40% up)

– Simulation for HKS tracking efficiency by D.Doi– e,e+ B.G

• mix rate is high especially for 52Cr 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

pe+ : 1.2±0.5 [GeV/c]θ : 0.124±0.124 [rad]φ : 2.64159±0.5 [rad]target : 12C 100[mg/cm2]

HKS D magnetHKS D magnet

Splitter magnet

beam:spherical uniform generation

no collimatorEM flag on