Collaboration. Cambridge ILC software tools meeting

Transcription

1 Ronen Ingbir Cambridge ILC software tools meeting

2 FCAL Goals : design and construction of Vinča Institute of Nuclear Sciences, Belgrade AGH University, Cracow Institute of Nuclear Physics, Cracow Luminosity detector Beam monitor Photons calorimeter Jagellonian University, Cracow University of Colorado DESY Joint Institute Nuclear Research Dubna National Center of Particle & HEP Minsk Brookhaven NY Prague Acad. of Science Institute HEP Protvino

3 FCAL simulation tools Detector simulation: Geant-3, Geant-4 (and Mokka) next step: G3/G4 comparison Physics: BHWIDE, CIRCE, GUNIEA-PIG, WHIZARD High statistics / Fast detector simulation Electronics simulation: noise, dead cells, digitization (Geant-3 + Fortran code)

4 BeamCal Detection of electrons/photons at low angle Shielding the inner detector Beam diagnostics from beamstrahlung electrons/positron pairs.

5 Beam diagnostics : BS Pairs Observables (examples): Christian Grah, total energy DESY-Zuethen first radial moment left/right, up/down, forward/backward asymmetries detector: realistic segmentation, ideal resolution, bunch by bunch resolution Solved by matrix inversion (Moore-Penrose Inverse) 1 st order Taylor-Exp. Observables Observables nom Taylor = + * Matrix Δ BeamPar Being tested also for the 20mrad case

6 Particle identification in the BeamCal The Physics: SUSY particles production Signature: missing energy The Background: two photons event Signature: missing energy (if electrons are not tagged) Excellent electron identification is needed down to as small angle as possible

7 Electron detection in the BeamCal 4 mm 10 mm 20 N rings N cells 1660 N channels N rings N cells 264 N channels Lost particles for R < 55 mm Inefficiency to identify Low BG (ϕ ~ 0 ) High BG (ϕ ~ 90 ) 5mm 8mm 10mm High BG (ϕ ~ 90 ) 5mmelectrons 200 GeV 8mm 10mm Low BG (ϕ ~ 0 )

8 Electron detection for different beam parameters

9 X-angle & magnetic field

10 Distribution of BeamStrahlung pairs Headon Christian Grah, DESY-Zuethen 2 mrad

11 20mrad crossing angle and DID field 20 mrad, DID 20 mrad, DID extended Rmax

12 Anti DID 20 mrad, DID 20 mrad, anti DID

13 BeamCal Geant4 Simulation Need precise simulation for showering/realistic bfield map. Includes: flexible geometry (beam crossing angle, layer thickness, variable segmentation, calorimeter tilt) simplified DiD/antiDiD magnetic field input GP generated e+e- pairs output root tree with energy distribution in segments 1 BX ~ 2.4 GHz CPU A.Sapronov Shower visualization Energy/Layer distribution

14 B field Map Energy deposited in the sensors of BeamCal. All layers Layer 8

15 LumiCal Precise measurement of the luminosity by using Bhabha events Extend coverage of the ILC detector

16 Counting Bhabha events No Events Events Energy (GeV) Yes Min Max θ (rad) R ~10 cm ~25 cm θ 33 mrad 80 mrad

17 X- angle background Beamstrahlung pair background 6.E mrad, DID Number of Bhabha events per year 5.E+09 4.E+09 3.E+09 2.E+09 1.E+09 0.E+00 Events per year Background (GeV) 250 GeV R min (cm) Background (GeV) Christian Grah, DESY-Zuethen

18 Four-lepton processes M.Pandurović / I. Božović-Jelisavčić, Belgrade Simulation of e + e - e + e l + l - (l = e, μ, τ): WHIZARD Bhabha scattering: BHLUMI Detector: Geant-3 Y [CM] signal Background Background x [cm] x [cm] LUMICAL BEAMCAL LUMICAL BEAMCAL Y [CM] Energy [Gev] θ [deg] x [cm] x [cm]

19 Strip design - signal digitization Bogdan Pawlik, Cracow Geant-3 + Fortran code analog 8-bit ADC σ(θ) [rad] (3.11±0.01) 10-5 (3.07±0.01) 10-5 Δθ/θ (2.1±0.3) 10-5 (2.3±0.3) 10-5 σ(φ) [rad] (1.4±0.1) 10-3 (1.4±0.1) 10-3

20 Fast Simulation

21 Luminosity precision determination Based on BHWIDE N1 : Reconstructed and generated in acceptance region. N2 : Generated in acceptance region but reconstructed outside. N3 : Generated outside acceptance region but reconstructed inside. ΔL L = ΔN N = N rec N N gen gen = N N 3 1 N + N 2 2 Δ L δ L = ( N N 2 ) σ N + ( N 1 + N 3 ) σ ( N 1 N 2 ) 1 N ( N + N ) σ 2 N

22 Fast detector simulation bias Changing the bias with a fixed resolution. ΔL L = 2* Δθ θ min

23 Fast detector simulation resolution Changing the detector resolution with no bias

24 Outgoing beam flat azimuthal distribution X (cm) Events Events Y (cm) Y (cm) X (cm) ϕ (rad) ϕ (rad)

25 Bhabha Scattering 20mrad X-angle Detector axis Events Y (cm) ϕ (rad) X (cm)

26 Headon, 14,20 mrad X-angle outgoing beam 14 mrad X-angle detector axis 20 mrad X-angle detector axis

27 Headon, 14,20 mrad X-angle outgoing beam 14 mrad X-angle detector axis 20 mrad X-angle detector axis

28 20mrad X-angle Detector axis Y (cm) N 3 N 1 N 4 N 2 X (cm)

29 Beam position 1 mm beam shift 0.5 mm beam shift 0.3 mm beam shift Events (up down) ϕ Calibration y = 5E-05x Beam shift (cm) Events Events (right left)

30 20mrad X-angle Detector axis Before correction after correction ΔL/L~10-3 But!!!!!! ΔL/L~10-2 This is assuming knowing in perfect precision many parameters

31 Present Understanding

32 20 mrad LDC BeamCal (bigger outer radius) Detailed detector design recommendation LumiCal (bigger inner radius)