Pixel TPC simulations in the ilcsoft ILD framework Kees Ligtenberg Nikhef lepcol gridpix meeting 10 october 2016 Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 1 / 13
Outline Overview of simulation framework 1 Simulation of pads and pixels 2 Muon example event display for pads and pixels 3 Resolution in simulation 4 Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 2 / 13
Overview of the ilcsoft framework for the TPC Ilcsoft is the collection of software for the ILC/ILD Simulation in geant4 using the DD4HEP detector description tool Reconstruction using processors in the modular Marlin framework ◮ Marlin processors should also use DD4HEP, but the TPC processors still use the deprecated GEAR Ilcsoft installed on lepcol project space at Nikhef ◮ found at /project/lepcol/ilcsoft/ ◮ setup environment with source /project/lepcol/ilcsoft/v01-17-10/init ilcsoft.sh Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 3 / 13
Overview of the ilcsoft framework for the TPC Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 4 / 13
Simulation of pads 1 Detector described by DD4HEP geometry is y loaded. Sensitve gas volumes are made 2 Geant4 processes interactions of particle(s) from gun or event x 3 Single hit in TPC is deposited if energy above threshold (32eV) in a single pad. Position of pad centre crossing is recorded 4 TPC hits are smeared by expected resolution in Volumes are organised TPCDigiProcessor. Hits can migrate to other as tube shaped layers, pads there are no pad 5 Smeared hits are used as input for columns reconstruction Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 5 / 13
Simulation of pixels Simulate pixels as small pads ◮ Shrink pad size from 6 × 1 mm to 0.055 × 0.055 mm ◮ Allow multiple deposits per pixel crossing before smearing ◮ Requires replacement of the the GEAR geometry by the DD4hep geometry Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 6 / 13
Pad event display and muon track display single 50 GeV µ − track t ¯ t event display Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 7 / 13
Pixel muon track display single 50 GeV µ − track Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 8 / 13
Hits along track Number of hits by distance from origin hitsByDistanceFromOrigin hitsByDistanceFromOrigin Hits Entries Entries 12937 12937 Mean Mean 1724 1724 1000 544.7 544.7 Std Dev Std Dev 800 600 400 200 0 0 500 1000 1500 2000 2500 Distance [mm] More than 10 000 hits for a 50 GeV muon track for pixels, compared to 170 for pads Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 9 / 13
Resolution as function of drift length m] µ [ 350 φ r σ 300 250 200 150 100 Simulated resolution 50 Parameterized function for resolution 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 z [mm] Resolution is better closer to the endplate, at larger z Simulated resolution is standard deviations of distance to track Function is smearing magnitude Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 10 / 13
Orthogonal distance in z slices normalised Hits 0.5 Z slice 500 < z < 1000 mm, magnitude in XY plane Z slice 1000 < z < 1500 mm, magnitude in XY plane Z slice 1500 < z < 2000 mm, magnitude in XY plane 0.4 Z slice z > 2000 mm, magnitude in XY plane 0.3 0.2 0.1 0 − − − 1500 1000 500 0 500 1000 1500 µ Distance [ m] Resolution for different z Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 11 / 13
Pull diagrams of drift distance in z slices normalised Hits Z slice 500 < z < 1000 mm, magnitude in XY plane 0.08 Z slice 1000 < z < 1500 mm, magnitude in XY plane Z slice 1500 < z < 2000 mm, magnitude in XY plane 0.07 Z slice z > 2000 mm, magnitude in XY plane 0.06 0.05 0.04 0.03 0.02 0.01 0 − − − 3 2 1 0 1 2 3 Distance pull Pull is gaussian Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 12 / 13
Conclusion The Ilcsoft framework is installed Pixel sized pad simulation works for particle gun tracks Next steps: ◮ Change pixel TPC hit deposit action. Currently simulation takes hours for t ¯ t event ◮ Look into reconstruction of tracks ◮ Replace GEAR by DD4Hep for reconstruction code Kees Ligtenberg (Nikhef) Pixel TPC simulations 10 october 2016 13 / 13
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