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7/6/2011 ECAL Studies 1/7 ECAL Studies Jacopo Nardulli

ECAL Studies

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ECAL Studies. Jacopo Nardulli. Why the ECAL is as it is ?. The LOI ILD Ecal structuring comes from an old optimization from H. Videau available here ECAL Optimization from H. Videau He considers a few scenarios with different nr of layers and different absorber thickness - PowerPoint PPT Presentation

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7/6/2011 ECAL Studies 1/7

ECAL Studies

Jacopo Nardulli

7/6/2011 ECAL Studies 2/7

Why the ECAL is as it is ?

• The LOI ILD Ecal structuring comes from an old optimization from H. Videau available here

ECAL Optimization from H. Videau

• He considers a few scenarios with different nr of layers and different absorber thickness

• Similar studies have now also been done by a LLR PhD student M.S.Amjad and have been presented at the CALICE Meeting in Casablanca

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Two possible studies•Keep same radiation length: ECAL with less layers• Less expensive, energy resolution can be worse, as

the pattern recognition• Varying nr of layers and absorber thickness, not the Si

thickness

•Change the radiation length: ECAL with less layers• Less expensive, overall performance changes

• If I change the X0, can have more leakage into the HCAL which could be fixed with a combined ECAL/HCAL analysis

• Varying nr of layers, absorber thickness and studying performance as a function of the X0 similar to what Angela has done for HCAL.

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Now only first study: Different ECAL models• Altering the number of layers and their absorber thickness in

such a way that Total Absorber thickness in the detector remains the same.

• The analyses included in this talk were done with Single Photon with θ and φ varying in the full range and Energies of 1, 10, 100 and 500 GeV

• Default model 20 layers in 1st stack and 9 layers in 2nd stack

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Disclaimers• Here showing the Energy Resolution vs. the Energy but to get the

energy resolution I am not using the official MarlinProcessor which does that –rms90 and mean90- but single Gaussian fits.

• So do not look at absolute numbers, but at the general trend of the plots

• THIS IS WORK IN PROGRESS: Not all plots are fully understood

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Results: changing nr layers in 1st stack

• Energy resolution degrades for low energy

• We fail to get all the energy and the mean is much lower than the input Energy

Need to use different calibration constants Mean Rec. Energy vs Input EnergyMean Rec. Energy vs Input Energy

Energy Res. vs Input EnergyEnergy Res. vs Input Energy

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Results: changing nr layers in 2nd stack

Mean Rec. Energy vs Input EnergyMean Rec. Energy vs Input Energy

Energy Res. vs Input EnergyEnergy Res. vs Input Energy

• Energy resolution degrades, while we have lower degradation in the rec. of all the energy in the event

• Changing 2nd stack affects high energy photons which deposit more energy

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Results: changing nr layers in 1st and 2nd stack

Mean Rec. Energy vs Input EnergyMean Rec. Energy vs Input Energy

Energy Res. vs Input EnergyEnergy Res. vs Input Energy

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Spares• All same plots in barrel and forward region

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Barrel Results: changing nr layers in 1st stack

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Barrel Results: changing nr layers in 2nd stack

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Barrel Results: nr layers in 1st and 2nd stack

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Forward Results: changing nr layers in 1st stack

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Forward Results: changing nr layers in 2nd stack

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Forward Results: nr layers in 1st and 2nd stack