Particle Identification with Disc DIRC at PANDA

Transcription

1 Particle Identification with Disc DIRC at PANDA Mustafa Schmidt, Simon Bodenschatz, Michael Düren, Erik Etzelmüller, Klaus Föhl, Avetik Hayrapetyan, Julian Rieke TIPP 217 May 23, 217 Mustafa Schmidt Particle Identification with Disc DIRC / 16 /16

2 Outline 1 Detector Concept 2 Detector Performance 3 DESY Testbeam Summary & Outlook Mustafa Schmidt Particle Identification with Disc DIRC 1 / 16 1/16

3 PANDA Spectrometer Kaon phase space: 2/16 Mustafa Schmidt Particle Identification with Disc DIRC 2 / 16

4 Detector Overview Opening angle of Cherenkov Cone: ( ) 1 θ C = arccos n(λ)β with β = p/(m 2 + p2 ). mirror FEL z(φ') filter MCP-PMT particlestrack bar φ' ASICSreadout segmented PMTSanode Number of photons per track length according to Frank-Tamm-Formula: dn dx = 2παz 2 λ2 λ 1 ( ) 1 λ 2 1 n 2 (λ)β 2 λ 2 dλ θ c Photons/Event for π ± with 4 GeV/c momentum Φ rel radiator Mustafa Schmidt Particle Identification with Disc DIRC 3 / 16 3/16

5 Geometrical Model for Reconstruction FEL Particle Radiator Disk θ c ϕ particle α FEL tan ϕ = tan ϕ tan α FEL φ rel ϕ θ c = arccos(sin θ p cos φ rel cos ϕ + cos θ p sin ϕ) Mustafa Schmidt Particle Identification with Disc DIRC 4 / 16 4/16

6 Reconstruction Algorithm Input Parameters x p, y p, θ p, φ p, (t p) Mass Hypotheses m π, m K, m p Detected Hit Pattern n FEL, z, t Photon Propagation s ph, t ph Theoretical Hitpattern n FEL,theo, z theo Spatial Cut z z theo < z thresh Time Cut t t theo < t thresh Likelihood Value N ln L = (ln G(z i z pred,i ; σ z ) + ln G(t i t pred,i ; σ t )) (1) i= Mustafa Schmidt Particle Identification with Disc DIRC 5 / 16 5/16

7 Tracking Information Helix Parameters: Calculation of curvature from magnetic field: ρ[m] = p T [GeV].3B[T] x (λ) = x + Qρ cos(qλ φ ) y (λ) = y + Qρ sin(qλ φ ) Position [mm] Angle [mrad] Momentum [GeV/c] Momentum [GeV/c] Mustafa Schmidt Particle Identification with Disc DIRC 6 / 16 6/16

8 Monte-Carlo Simulation Optical parameters in Monte-Carlo simulations: 1. Mean Cherenkov Angle Resolution transmission/efficiency fused silica epoxy Al-coating edge-filter optical grease PC blue PC green efficiency I efficiency II Cherenkov Angle Resolution [mrad] wavelength [nm] Wavelength [nm] events with π + at p = 4 GeV/c, θ = 12, φ = 45 : Pixel 9 Simulated Hitpattern Pixel 9 Predicted Hitpattern FEL FEL Mustafa Schmidt Particle Identification with Disc DIRC 7 / 16 7/16

9 Performance Analysis Separation power for different polar angles and momenta: Entries Separation Power vs. Polar Angle Mean Cherenkov Angle Resolution 3 Separation Power: Pion Resolution Kaon Resolution 4 Separation Power Blue Cathode Green Cathode 25 2 GeV/c 2 GeV/c 3 GeV/c 3 GeV/c 4 GeV/c 4 GeV/c Cherenkov Angle [rad] 2D scan (polar and azimuth angles) for p = 4 GeV/v: Azimuth Angle [deg] Mean: Separation Power Separation Power [nσ] Azimuth Angle [deg] Polar Angle [deg] Mean: Photon Hits Number of Hits Polar Angle [deg] Polar Angle [deg] Mustafa Schmidt Particle Identification with Disc DIRC 8 / 16 8/16

10 Benchmark Channel Analysis Benchmark Channel: p p f π π K + K : Kaon Distribution p p f (15) π Polar Angle Distribution 1.5 GeV/c < p < 4 GeV/c Momentum [GeV/c] Entries Kaon 2 Polar Angle θ [deg] Entries Polar Angle [deg] θ Kaon identification: Kaon Polar Angle [deg] 1 θ Pion misidentification: Entries Reconstructed Events Identified Events Entries Reconstructed Events Identified Events Invariant Mass [GeV] Invariant Mass [GeV] Mustafa Schmidt Particle Identification with Disc DIRC 9 / 16 9/16

11 Testbeam Setup DESY testbeam setup for T24/1 hall: TOFPET: Free running readout device with 5 ps time resolution Mustafa Schmidt Particle Identification with Disc DIRC / 16 /16

12 Radiator Setup Testbeam radiator: Fused silica plate (5 cm 5 cm fused silica plate with 1 nm surface roughness) Mustafa Schmidt Particle Identification with Disc DIRC 11 / 16 11/16

13 Testbeam Fotos 12/16 Mustafa Schmidt Particle Identification with Disc DIRC 12 / 16

14 Measured Hitpattern Pixel Angle Scan FEL Angle of Incidence [deg] Angle Scan FEL Hits/Trigger Pixel Y-Scan FEL Y-Position [mm] Y-Scan FEL Hits/Trigger Pixel Angle of Incidence [deg] Hits/Trigger Pixel Y-Position [mm] Mustafa Schmidt Particle Identification with Disc DIRC 13 / Hits/Trigger 13/16

15 Testbeam Results Single photon resolution and photon yield: Single Photon Resolution FEL1 Photon Yield FEL1 Single Photon Resolution [mrad] MC Simulation Testbeam Data Number of Hits MC Simulation Testbeam Data Angle of Incidence [deg] Event combination for vertical scan: Angle of Incidence [deg] Single Photon Resolution Mean Cherenkov Angle Entries 35 3 Testbeam Data Entries Testbeam Data MC Simulations MC Simulations 25 Double Gaussian Fit Gaussian Fit Cherenkov Angle [rad] Cherenkov Angle [rad] Mustafa Schmidt Particle Identification with Disc DIRC 14 / 16 14/16

16 Conclusion & Outlook Monte-Carlo studies for TDR regarding detector performance completed Reconstruction & PID algorithms ready and tested Successfull Disc DIRC test in October 216 at DESY testbeam Further tests for photon yield and single photon resolution in cosmics test stand possible Benchmark channel analysis in progress Studies regarding online reconstruction promising and ongoing 15/16 Mustafa Schmidt Particle Identification with Disc DIRC 15 / 16

17 Thank you very much for your attention! Mustafa Schmidt Particle Identification with Disc DIRC 16 / 16 16/16