1. LAT performance studies
Results from Cracow
(by A.Kowal, B.Pawlik, L.Zawiejski)
L.Suszycki
AGH University of Science and Technology Cracow

2. Forward Calorimetry Region with new design of the Mask
LAT parameters:
distance from the IP cm
radial dimensions cm
angular coverage
26.2<<82 mrad
0<<360 deg
L. Suszycki
Prague, April 2004

3. LAT detector versions Switching the geometry:
From the conical one (TDR version)
to the cylindrical one.
Two competitive structures of the Si/W sandwich calorimeter are considered:
Si pads
Si strips
L. Suszycki
Prague, April 2004

4. Simulated LAT pad-structure
Si pads/W calorimeter
16 cylinders (in r)
30 rings (in z)
24 sectors (in )
=> channels
analyzed angular range:
30<<78 mrad
0<<360 deg
L. Suszycki
Prague, April 2004

5. Simulated LAT pad-structure 2 Large statistics behaviour
Angular reconstruction not satisfactory –
Simple reconstruction bias and resolution ~ mrad,
(with 16 cylinders),
can be reduced at price of large #channels
L. Suszycki
Prague, April 2004

6. Stripped LAT description
LAT consists of 30 tungsten disks
Each disk has silicon strip detector attached
Every second detector has either 120 radial or 64 concentric strips
In total there is 2960 read-out channels
L. Suszycki
Prague, April 2004

7. Stripped LAT reconstruction Accuracy of order 0
Stripped LAT reconstruction Accuracy of order 0.5x10-4 radian in measuring polar angle Measurement of 250GeV electron energy with accuracy 5GeV (ΔE~0.31√E)
L. Suszycki
Prague, April 2004

8. Stripped LAT - Bhabha events Measurement of the scattered electron energy with accuracy 7GeV (ΔE~0.44√E)
Egen - Erec
L. Suszycki
Prague, April 2004

9. Stripped LAT - Bhabha events 2 Reconstruction of energy of the back-to-back electron pair
E (GeV)
L. Suszycki
Prague, April 2004

10. Stripped LAT - Bhabha events 3 Reconstruction of theta angle of the back-to-back electron pair
Gen.
Rec.
θ (mrad)
L. Suszycki
Prague, April 2004

11. Stripped LAT - Bhabha events 4 Acolinearity
θL – θR (mrad)
L. Suszycki
Prague, April 2004

12. Stripped LAT - Bhabha events 5 Angle reconstruction accuracy ~0
Stripped LAT - Bhabha events 5 Angle reconstruction accuracy ~0.09 mrad
θgen – θrec (mrad)
L. Suszycki
Prague, April 2004

13. Beamstrahlung background
No photons are seen in LAT (θ>26 mrad)
L. Suszycki
Prague, April 2004

14. Beamstrahlung background 2
L. Suszycki
Prague, April 2004

15. Beamstrahlung background 3 Pairs from beamstrahlung in LAT angular range
L. Suszycki
Prague, April 2004

16. Beamstrahlung background 4 Energy from beamstrahlung in LAT angular range
Background may be present at rmin
(deg)
and azimuthal angle 0/180 degrees
(deg)
L. Suszycki
Prague, April 2004

17. Summary
LAT with pads: reconstruction algorithm to be improved or changed completely
Stripped LAT: seems ok
Bhabha events: in progress
Beamstrahlung: needs detector simulation
L. Suszycki
Prague, April 2004

18. The end
Thank you

19. Notices Stripped LAT: E_rec = 60.79*E_seen
Generated events, reconstr (26 – 86 mrad)
Beamstrahlung: TDR, FC Proposal TeV/bx, Jeju 20 TeV
A.Stahl 500 TeV/bx photons, 100 TeV/bx pairs
(in BeamCal 5 TeV/bx and 20 TeV/bx) – Zeuthen Nov 2002
L. Suszycki
Prague, April 2004

20. Reconstruction results (512ch)
L. Suszycki
Prague, April 2004