PXD Resolution in Large Occupancies Z. Drsal , K. Prothmann - - PowerPoint PPT Presentation

PXD Resolution in Large Occupancies

• Z. Drásal  , K. Prothmann 

Charles University Prague  MPI Munich

29th Sep 2010 2 5th International Workshop on DEPFET Detectors and Applications

Outline

• ILC Software (Marlin) → new implementation of background simulations + added

effects of ganged pixels in simulation of PXD response

– MergeBackground: new Marlin processor merging signal Mokka hits with background

hits (Belle II QED background) into common ILC collection (PXD, SVD, CDC)

– SiPxlDigi: Marlin processor improved with simulation of effects of ganged pixels

• PXD resolution studies in large QED background (~ % PXD occupancy studies)

performed – preliminary results

– Resolution studies – Efficiency studies (resp. inefficiency due to high background) – Impact parameter studies (not complete yet)

29th Sep 2010 3 5th International Workshop on DEPFET Detectors and Applications

ILC Software for Belle II – MergeBackground processor

Reconstruction Simulation

Mokka

(Geant4)

GEAR (XML)

Geometry information

LCIO (persistency data model) Pythia

Generator

ROOT LCIO

LCCD

HEPEvt (ASCII)

Generated events

Marlin

MaterialDB MergeBackground Digitization

...

Optimization

ILC Software Scheme

• Marlin processor: MergeBackground

– merges together:

• collection of signal hits (physics events)
• collection of background hits (QED

background) → overlay several *.slcio files to get required (expected)

• ccupancy

PXD Signal Hits Background Hits _0 Background Hits _1 Background Hits _2 Background Hits _3 PXD Merged Hits

29th Sep 2010 4 5th International Workshop on DEPFET Detectors and Applications

Simulations at Large Occupancies

• Simulated single muon tracks (Mokka, 500MeV) in standard ILC software chain
• Merged signal (muons) & background hits (Belle II QED background) with
• ccupancies:

– 0 % (no background) – 5 – 6 % – 10 – 12 % – 15 – 18 %

• Studies of DEPFET (no ADC) w/o ganged pixels (2 pixel signals summed up and

read-out by common drain; 0 – 400 row, 1 – 401 row, 2 – 402, …):

– resolutions in R-Phi & Z, resp. their degradation in “harsh” background – TrackerHit efficiency (hit is OK if found by clustering algorithm & if major contribution to the

signal is from simulated SimTrackerHit) → nonefficiency degrades resolution: hit found, but not coming from original particle (background effect – hits overlayed) or not found at all (signal/noise too low → clustering doesn't find it)

– impact parameter resolution & track efficiency

29th Sep 2010 5 5th International Workshop on DEPFET Detectors and Applications

Results: PXD Resolution in R-Phi in Large Occupancies

• Left: 1s

t & 2n d layer – noGanged x Right: 1s t & 2n d layer – ganged

29th Sep 2010 6 5th International Workshop on DEPFET Detectors and Applications

Results: PXD Resolution in Z in Large Occupancies

• Left: 1s

t & 2n d layer – noGanged x Right: 1s t & 2n d layer – ganged

29th Sep 2010 7 5th International Workshop on DEPFET Detectors and Applications

Results: PXD Cluster Size in Large Occupancies

• Left: 1s

t & 2n d layer – noGanged x Right: 1s t & 2n d layer – ganged

29th Sep 2010 8 5th International Workshop on DEPFET Detectors and Applications

Results: PXD Efficiency in Large Occupancies

• Left: PXD – noGanged x Right: PXD – ganged

29th Sep 2010 9 5th International Workshop on DEPFET Detectors and Applications

Results: Tracking Efficiency

• PXD with ganged pixels + SVD: all in 5 – 6 % occupancy

P [GeV] P [GeV] 500 MeV Muons 2.5 GeV Muons

0.5 GeV Eff. 0.5 GeV Purity 2.5 GeV Eff. 0.5 GeV Purity ganged 98.15 99.46 unganged 98.19 99.48 Error: +- 1%

29th Sep 2010 10 5th International Workshop on DEPFET Detectors and Applications

Results: Track Multiplicity

• PXD w/o ganged pixels + SVD: all in 5 – 6 % occupancy

Number of tracks Number of tracks Number of tracks Number of tracks 500 MeV Muons Ganged pixels 500 MeV Muons Unganged pixels 2.5 GeV Muons Ganged pixels 2.5 GeV Muons Unganged pixels

29th Sep 2010 11 5th International Workshop on DEPFET Detectors and Applications

Results: Z0 Impact Parameter Resolution

• PXD w/o ganged pixels + SVD: all in 5 – 6 % occupancy

500 MeV Muons Ganged pixels 500 MeV Muons Unganged pixels Z0 [mm] Z0 [mm] Pseudo momentum [GeV] Pseudo momentum [GeV]

29th Sep 2010 12 5th International Workshop on DEPFET Detectors and Applications

Conclusions

• Tools for background studies implemented (MergeBackground processor)
• Tools for simulation of ganged pixels implemented (SiPxlDigi processor)
• Preliminary studies in high QED background performed, but too high occupancies

→ necessary to complete the study for 1%, resp. 2% QED background

29th Sep 2010 13 5th International Workshop on DEPFET Detectors and Applications

Deposited Energy in PXD

• 75(µm) - 90deg, 90(µm) - 56deg, 105(µm) - 45deg, 120(µm) - 38deg ...