1. Luminosity Measurement using BHABHA events
Tel Aviv University HEP experimental Group
MDI
SLAC
Ronen Ingbir
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

2. Strip design ΔE~0.31√E L R Cracow
Lumical - A Future Linear Collider detector

3. Pad design
15 cylinders * 24 sectors * 30 rings = cells
8 cm
0.31 cm Silicon
28 cm
0.34 cm Tungsten
Cell Size
1.3cm*2cm>
1.3cm*6cm<
~1 Radiation length
~1 Radius Moliere L R
6.10 m
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

4. Reconstruction Algorithm
We explored two reconstruction algorithms:
Events Num.
T.C Awes et al. Nucl. Inst. Meth. A311 (1992) 130.
The log. weight fun. was designed to reduce steps in a granulated detector :
1. Selection of significant cells.
2. Log. smoothing.
Log. weight.
E weight.
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

5. Logarithmic Constant 400 GeV Constant value Constant value
After selecting:
We explored a more systematic approach.
The first step is finding the best constant to use under two criteria:
1. Best resolution.
2. Minimum bias.
Constant value
Constant value
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

6. Energy dependent constant
The goal is to find a global weight function.
Is the the log. weight constant really a constant ?
Constant value
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

7. Shower reconstruction
What happens when we select the best log. weight constant ?
Num. of Cells
Num. of Sectors
Shower size
Log. Weight Selection
Energy portion (%)
Num. of Cylinders
Most of the information is in the selected cells.
En>90%
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

8. Magnetic field Lumical - A Future Linear Collider detector
HEP Tel Aviv University

9. Background studies BHWIDE + CIRCE
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

10. Geometric acceptance In Eout-Ein P= Eout+Ein Out Energy Resolution
3 cylinders
33 mrad
2 cylinders
1 cylinders
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

11. Left-Right balance L R Simulation distribution
Distribution after acceptance and energy balance selection
Right signal - Left signal
Left side detector signal
Right side detector signal
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

12. Energy resolution Ntuple 31% 29% 42% 24% 45% 46% 25% 49% No cuts
Ntuple
No cuts
With cuts
Pure electrons
31%
29%
Bhabha
42%
24%
Bhabha + Beamstrahlung
45%
Bhabha + Beamstrahlung + Beam spread (0.05%)
46%
25%
Bhabha + Beamstrahlung +
Beam spread (0.5%)
49%
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

13. Angular resolution Lumical - A Future Linear Collider detector
HEP Tel Aviv University

14. ‘Pure’ electrons simulation
Bias study
‘Pure’ electrons simulation
Bhabha+Beam+BS(5e-4)
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

15. Real life algorithm
Working with both sides of the detector and looking at the difference between the reconstructed properties:
(In real life we don’t have generated properties)
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

16. Dense design 0.1 cm Silicon 0.55 cm Tungsten 0.34 cm Tungsten
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

17. Moliere radius & Radiation length
Detector Signal
0.8cm
1.1cm
Z (cm)
30 radiation length detector
47 radiation length detector
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

18. New geometric acceptance
Events
Energy Resolution
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

19. Optimization Lumical - A Future Linear Collider detector
HEP Tel Aviv University

20. Margins in between cells
Energy resolution
Polar resolution
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

21. Maximum peak shower design
Our basic detector is designed with
30 rings * 24 sectors * 15 cylinders = 10,800 channels
Do we use these channels in the most effective way ?
20 cylinders
10 cylinders
24 sectors * 15 rings * (10 cylinders + 20 cylinders) = 10,800 channels
4 rings
15 rings
11 rings
30 rings cylinders
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

22. Polar reconstruction Maximum peak shower design Basic Design
0.11e-3 rad
0.13e-3 rad
Constant value
Angular resolution improvement without changing the number of channels
Other properties remain the same
Constant value
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

23. High Statistics MC BHWIDE + fast detector simulation
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

24. R&D status & future steps
Pure electron MC
Detector properties
Events selection
‘Real physics’ MC
Bhabha + Beamstrahlung + Beamspread
High statistics MC
Luminosity with a crossing angle
Luminosity with polarised beams (Gideon Alexander)
‘Real physics’ MC + digitization + elec. noise + New max peak design + Margins
Final optimization
Lumical - A Future Linear Collider detector
HEP Tel Aviv University

25. THE END Lumical - A Future Linear Collider detector
HEP Tel Aviv University