1. Current Status of EMC Reconstruction
He Miao
2005/7/21

2. outline EMC reconstruction event model . Data flow. Energy correction.
Position correction.
EMC end-cap reconstruction algorithm.
Beam-test data analysis with EMC reconstruction package and improvement.

3. EMC reconstruction event model
EmcRecDigit
EmcRecID, EmcRecADC, EmcRecTDC
EmcRecHit
EmcRecID, EmcRecEnergy, EmcRecTime
EmcRecFraction : public EmcRecHit
EmcRecFrac
EmcRecCluster
EmcRecID, EmcRecHitMap
EmcRecShower
EAll, ESeed, E3x3, E5x5, Position, NearestSeed

4. Data Flow Digit Hit Cluster Shower Input: Emc Digit TDS Output:
Emc Rec Shower
TDS
Root
Emc Mc Hit

5. Energy correction

6. Test of EMC reconstruction package theta position
σtheta≈6mm

7. Test of EMC reconstruction package phi position
σphi≈6mm

8. Position correction
correction parameters
σ=4.1mm

9. Digitization Non-uniformity of Light Output Photo statistics
Background
Electronics noise

10. EMC end-cap reconstruction algorithm
Cluster finding
Neighbor definition: 3×3
Red, green and blue are neighbors.
Hitmap output
j-1
i-1 i,j i+1
j+1

11. Cluster finding end-cap29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

12. Cluster finding endcap
Sector i+1
Sector i 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

13. Cluster finding endcap
Sector 3
Sector 4 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
20mm gap

14. Hitmap barrel
theta
phi

15. Hitmap endcap

16. Hitmap endcap 29 28 27 26 25 24 23 22 21 20 19 18 * 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Hit between two sectors

17. Beam-test data analysis
Beam-test result
Test2 - 6×6 matrix – April
Test3 - 3×3 matrix
Test3 - 5×5 matrix
Test4 - 6×6 matrix – with MDC
Splitting algorithm
Time information

18. Test3 - 5×5 matrix
3×3,σE/E=2.92% 5×5,σE/E=2.95%
In boss, σE/E=3.65%

19. Split shower with distance to seed
r13=sqrt(x13^2+y13^2)
r23=sqrt(x23^2+y23^2)
e3=e3*weight1/weight_total +e3*weight2/weight_total
weight1=e1*f(r13)
weight2=e2*f(r23)
f2(r)=exp{-a*r/Mr}
Mr: Moliere radius=3.8cm
a: constant=2.5 e1 e3 e2
e3=e3*e1/(e1+e2) +e3*e2/(e1+e2)

20. Split shower absolutely
A hit belongs to nearest seed.
A hit whose distances to each seed are equal will be shared.
Take seed’s energy as weight. e1 e2

21. Split shower with distance to seed
Split shower absolutely
σE/E=2.96%

22. Time information time 18 - 24 3.29% 14 - 30 3.10% 10 - 40 3.11% 0 - 60
resolution
3.29%
3.10%
3.11%
0 - 60
3.13%

23. Reconstructed showers
No time information
t:14-30 split in hit
t:18-24 split in shower
t:14-30 split in shower

24. Conclusion of beam-test analysis
The improvement of splitting algorithm give better result (σE/E=2.94%) than before (σE/E=3.65%) , but not good enough.
Time information is important for background exclusion.
More research should be done.

25. Thank you!