Results of Forward Calorimetry Studies for the LAT Detector in Krakow
This paper presents the outcomes from the forward calorimetry studies for the LAT detector, focusing on new geometric designs and performance parameters. The analysis includes the transition from conical to cylindrical geometry and examines the reconstruction algorithms for both Si/W sandwich structures and silicon strip detectors. Key findings involve angular resolution challenges, accuracy in measuring the energy of Bhabha events, and background assessment due to beamstrahlung. The study aims to improve reconstruction algorithms and optimize detector design for enhanced performance.
Results of Forward Calorimetry Studies for the LAT Detector in Krakow
E N D
Presentation Transcript
LAT performance studies Results from Cracow (by A.Kowal, B.Pawlik, L.Zawiejski) L.Suszycki AGH University of Science and Technology Cracow
Forward Calorimetry Regionwith new design of the Mask LAT parameters: • distance from the IP 305-325 cm • radial dimensions 8-28 cm • angular coverage • 26.2<<82 mrad • 0<<360 deg Prague, 15-17 April 2004
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 LAT detector versions Prague, 15-17 April 2004
Simulated LAT pad-structure Si pads/W calorimeter • 16 cylinders (in r) • 30 rings (in z) • 24 sectors (in ) => 11520 channels • analyzed angular range: • 30<<78 mrad • 0<<360 deg Prague, 15-17 April 2004
Simulated LAT pad-structure 2Large statistics behaviour Angular reconstruction not satisfactory – Simple reconstruction bias and resolution ~0.2 - 0.3mrad, (with 16 cylinders), can be reduced at price of large #channels Prague, 15-17 April 2004
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 Prague, 15-17 April 2004
Stripped LAT reconstruction Accuracy of order 0.5x10-4 radian in measuring polar angleMeasurement of 250GeV electron energy withaccuracy 5GeV(ΔE~0.31√E) Prague, 15-17 April 2004
Stripped LAT -Bhabha eventsMeasurement of the scattered electron energy withaccuracy 7GeV(ΔE~0.44√E) Egen - Erec Prague, 15-17 April 2004
Stripped LAT -Bhabha events2Reconstruction of energy of the back-to-back electron pair E (GeV) Prague, 15-17 April 2004
Stripped LAT -Bhabha events3Reconstruction of theta angle of the back-to-back electron pair Gen. Rec. θ(mrad) Prague, 15-17 April 2004
Stripped LAT -Bhabha events4Acolinearity θL – θR (mrad) Prague, 15-17 April 2004
Stripped LAT -Bhabha events5Angle reconstruction accuracy ~0.09 mrad θgen – θrec (mrad) Prague, 15-17 April 2004
Beamstrahlung background No photons are seen in LAT (θ>26 mrad) Prague, 15-17 April 2004
Beamstrahlung background 2 Prague, 15-17 April 2004
Beamstrahlung background 3Pairs from beamstrahlung in LAT angular range Prague, 15-17 April 2004
Beamstrahlung background 4Energy from beamstrahlung in LAT angular range Background may be present at rmin (deg) and azimuthal angle 0/180 degrees (deg) Prague, 15-17 April 2004
Summary • LAT with pads: reconstruction algorithm to be improved or changed completely • Stripped LAT: seems ok • Bhabha events: in progress • Beamstrahlung: needs detector simulation Prague, 15-17 April 2004
The end Thank you
Notices Stripped LAT: E_rec = 60.79*E_seen Generated 20 000 events, reconstr. 9800 (26 – 86 mrad) Beamstrahlung: TDR, FC Proposal 20-40 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 Prague, 15-17 April 2004
Reconstruction results (512ch) Prague, 15-17 April 2004
