1. Full Simulation Session SuperB General Meeting
EMC Full Simulation
Full Simulation Session
SuperB General Meeting
Isola d’Elba
03/06/2010
S. Germani - C. Cecchi
INFN Perugia & Perugia University

2. Outline Updates on Background Studies
Clustering Optimization and Energy Resolution with Background
Fwd PID material effect
Conclusions and Outlook
03/06/2010
EMC FullSim Studies

3. Clustering From Nov. 09 Frascati Meeting No Clustering: Clustering :
Ecrystal > 1 MeV
Same as slac meetiong
Clustering :
Clustering algorithm as (supposed to be) in BaBar:
Start from maximum energtyCrystal
Look for crystal arount ME Xtal
Sum crystal energy if E > digi threshold ( MeV)
If a Crystal around the ME one has E > seed threshold (2-3 MeV) look around it too
Adapted for LSO
5 x x 3 Matrix
Take maximum energy crystal and a matrix of crystal arount it
100 MeV 
1 GeV 
From Nov. 09 Frascati Meeting
03/06/2010
EMC FullSim Studies

4. Particles per Integration Time
Number of particles enetring the
EMC volume:
Direction Selection
Outward bound cossing Inner Surface
Inward bound crossing Outer Surface
Particle Selection
 e : E > 20 MeV
n : all
03/06/2010
EMC FullSim Studies

5. Cluster Mc Match (QED Emin = Eseed)
Almost half clusters
Seem to be associated with
neutrons
Integartion Time
0.02 Cluster/BC x
200 BC ~ 4 Cluster
<< 40
Large differnce between neutrons
And gammas
Bunch Crossing
03/06/2010
EMC FullSim Studies

6. Cluster Particle Matching
EMC Volume Boundary
Cluster particle match performed
choosing the Track with the smaller
distance from the Cluster
BARREL
Fwd
03/06/2010
EMC FullSim Studies

7. Background Cluster Example
Follow the avolution of background cluster with the number of bunc crossings
Cluster Energy
First Seed Crystal Energy
Cluster Size
Distance prom original Position
Particle association
Most of Background Clusters come form
Overlapping of small energy deposits
Partcle association is not meaningful
03/06/2010
EMC FullSim Studies

8. Clustering News
Checking again what BaBar Clustering algorithm is supposed to be I found an addictional cut :
The crystal with the maximum energy in the cluster should have Emax>10 MeV
03/06/2010
EMC FullSim Studies

9. Signal + Background Private production of single photons with Bruno
Mix with RadBhabha events from February production
Sum all energy deposits in a given Time Windows
Perform clustering
Usually several clusters from background
Assign cluster to the Signal Photon
03/06/2010
EMC FullSim Studies

10. Time Window Width
100 MeV
500 MeV
For large windows resolution and distribution shape entirely
dominated by background
1 GeV
From Now On Time Window = 300 ns
03/06/2010
EMC FullSim Studies

11. Distribution Fit Crystal Ball Novosibirsk+Gauss
Measured Energy distibution changes with Energies
Some complex fit function tested
Keep using Crystal Ball function
03/06/2010
EMC FullSim Studies

12. Clustering: Time Window
Effect of Time Window Width on Energy resolution
Barrel
Fwd
Fit to be Checkd!
Fit to be Checkd!
Distribution shape changes widely with time window width
Need to perform less automated fit procedure
03/06/2010
EMC FullSim Studies

13. Clustering: Time Window 2
Effect of Time Window Width
on the number of extra cluster and anglular resolutuion
Number of Clusters
Theta Resolution
03/06/2010
EMC FullSim Studies

14. Clustering: Emax Energy Resolution Number of Clusters
Effect of Cut energy for crystal with amximum energy in the cluster
on Energy Resolution and Number of Clusters
Energy Resolution
Number of Clusters
03/06/2010
EMC FullSim Studies

15. Clustering: Eseed Barrel Fwd
Effect of Seed energy threshold on Energy resolution
Barrel
Fwd
03/06/2010
EMC FullSim Studies

16. Clustering: Eseed 2 Barrel Theta Resolution Number of Clusters
Effect of Seed Threshold Energy
Number of Clusters
Fwd Theta Resolution
03/06/2010
EMC FullSim Studies

17. Clustering: Edigi Barrel Fwd
Effect of Minimum Crystal Energy Threshold on Energy Resolution
Barrel
Fwd
03/06/2010
EMC FullSim Studies

18. Clustering: Edigi 2 Number of Clusters Theta Resolution (Barrel)
Effect of Minimum Crystal Energy Threshold
On Angular Resolution and Number of Clusters
Number of Clusters
Theta Resolution (Barrel)
03/06/2010
EMC FullSim Studies

19. Fwd PID Thickness
Current default Bruno geometry has 12 mm Quartz Fwd TOF (~10% X0)
Modify thickness : 0, 5, 10, 15, 25 % X0
03/06/2010
EMC FullSim Studies

20. PID Thickness Effect on σE
100 ns Time Window
300 ns Time Window
12 mm Quartz
(Bruno default)
12 mm Quartz
(Bruno default)
03/06/2010
EMC FullSim Studies

21. Conclusions and Outlook
Background has not negligible effect on reconstructed energy distribution
Clustering optimization has an impact on the resolution and on the number of clusters
Emax cut affects heavily the number of clusters
Fwd PID material up to 25% X0 has a small effect on Energy resolution with present background level
Time window width has a dominant effect at all energies
Readout chain simulation need to be more realistic
Interplay between Time Window Light Yield and Performance
Time resolution to exclude extra background clusters
Energy deposit storage in time slices may be needed for EMC
03/06/2010
EMC FullSim Studies