Mathieu Benoit

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Occupancy studies for CLIC_ILD inner layer and Update on Digitization : Tuning with data, Lorentz angle effects. Mathieu Benoit. Outline. First results on Occupancy for the inner layer of CLIC_ILD Following design from workshop - PowerPoint PPT Presentation

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Occupancy studies for CLIC_ILD inner layer and Update on Digitization: Tuning with data, Lorentz angle effects

Occupancy studies for CLIC_ILD inner layer and Update on Digitization: Tuning with data, Lorentz angle effectsMathieu BenoitOutlineFirst results on Occupancy for the inner layer of CLIC_ILD Following design from workshop

Inclusion of Magnetic Field effects in Digitization

DESY 2-4 GeV electrons data using Timepix single chip card

(sub) Barrel 0 orLeft Outer barrel(sub) Barrel 1 orLeft inner barrel(sub) Barrel 2 orCentral barrel(sub) Barrel 3 orRight inner barrel(sub) Barrel 4 orRight Outer barrelSimulationFor Now simulation of layer 0+1, results here for layer 0 , the most critical at r=29 mmSimulation with Livermore Low EM Physics listMax Step-size in Silicon =1 umInclude detla rays , fluorescenceGeometry : Magnetic Field = 4 TBerylium beam pipe (600um)Inside beampipe : air at 1 e-2 bar

Timepix-Like digitization 20x20um pixels 50 um thicknessResistivity = 10 kOhm cmThreshold = 500eLorentx angle not taken into account here

Plots are preliminary, need to include actual gap in phi Module 90 (top right) missing, being processedBarrel layout (layer 0+1)To ensure hermeticity, layer 0+1 need to be placed closer to IP than MC model Option 1:Radius(layer 1) = 29 mm (31mm before)Radius(layer 2) =30.87mm (32.87mm before) To avoid volume overlap, slightly tilt the ladders (here 1.5)Option 2: Tilt sensors by lorentz angle (ex: 15 deg)Add 1-2 ladders (here , 2-> Icosagon !)Move back to larger radius (here 31.221 mm)15/03/12mini workshop on engineering aspects of the CLIC vertex detectors5Barrel layout (layer 0+1, option 1)

An option to option 1: Shifting layer 2 vs layer 1 (here 1mm), ladder per ladder to avoid overlapping gapsSingle hitsDouble layer, holding on the same mechanical structure not shown here 15/03/12mini workshop on engineering aspects of the CLIC vertex detectors6Event Display (1k primary tracks)

HitMap in Layer 0

Hitmap Layer 0 (per Train per Chip)

Occupancy per module in layer 0

%Occupancy per module in layer 0 (polar view)

%Cluster size subbarrel 0 layer 0

Cluster size subbarrel 1 layer 0

Cluster size subbarrel 2 layer 0

Cluster size subbarrel 3 layer 0

Cluster size subbarrel 4 layer 0

HitMap in Layer 1

HitMap (per Train per mm2)

Occupancy per module in layer 1

%Occupancy per module in layer 0 (polar view)

%Cluster size subbarrel 0 layer 0

Cluster size subbarrel 1 layer 0

Cluster size subbarrel 2 layer 0

Cluster size subbarrel 3 layer 0

Cluster size subbarrel 4 layer 0

Occupancy Simulation2 Scenario : 20 um pixels, same geometry + B-Field effect, layer 0-5

25 um pixels, layer back by 4mm in r + B-field effects layer 0-5

In both scenario we need to add hadronic components, disksLorentz angleLorentz angle depends on mobility which depends on Electric field and eventually on dopant concentration

In a 50um 10kOhmcm p-type wafer, 10V bias, E[1600,2700]V/cmVary with resistivity, bias voltage

In a planar sensor, E is proportional to V appliedV applied is proportional to thickness2 (Full depletion voltage)For thin sensor, at full depletion voltage, Electric field is very lowTo be investigated : How much over Full depletion can we apply voltage

15/03/12mini workshop on engineering aspects of the CLIC vertex detectors27Lorentz angle effects in DigitizationI have added as an option in the digitizer to tak into account the Magnetic field in the motion equation of the charge in the sensor.

The Lorentz angle is calculated at each integration step taking into account :Local mobility and electric field Hall Scattering factor

Lorentz angle effects (0 degrees incidence, B=4T)

Lorentz angle effects (75 degrees incidence, B=4T)

Lorentz angle effects (0 degrees incidence, B=4T), tilted by Lorentz angle

Lorentz angle effects (0 degrees incidence, B=4T), tilted by Lorentz angle

Lorentz angle effects (Cluster Size)

!!Lorentz angle increases cluster size (in average) -> Increase occupancyDESY data with low energy (2-4 GeV) electronsWe were allowed to join ATLAS DBM testbeam at DESY to acquire some data with Timepix using low energy electrons (2-4 GeV) (No Tracking)6M Frames at 100V 0 deg5K Frames at 0,25,50,75 deg5k Frames at 0deg, 5V, 10V, 50V5k Frames at Ikrum 25,50,100In average 500 clusters per frameToT mode Some DESY plots (cluster size)

Some DESY plots (cluster size)

ConclusionDetailed simulation of inner layer for CLIC_ILD new design show higher occupancies than CDR numbers : Layer is 4 mm closer than before -> Higher occupancyPhi dependence observed in the end-of-stave chipsNext simulation to be perfomed with B-Field effects included, larger pixels

Lorentz angle effects have been encoded in the digitizerDebugged using the new event display feature of the digitizerReady for use in occupancies studies