Assessing the Effect of Miscalibrating the RD53B-CMS Readout Chip (CROC) to the Performance of the Inner Tracker (IT)

This page documents the

Introduction

List of Parameters

There are several parameters found in our chain of analysis, and they can be separated in two categories: experimental, i.e. the ones we are interested in tuning optimally and intrinsic, i.e. parameters that describe the clustering, pixel hit reconstruction (C, PXR respectively). The set of experimental parameters we wish to tune optimally are:

• Threshold (THR, electron units)
• Threshold Dispersion (THR_DISPERSION, electron units)
• Krummenacher Current (KRUM, DAC units)
• Krummenacher Dispersion (KRUM_DISPERSION, DAC units)
• Global DAQ Shift in Time (DELTAT, nanoseconds)
• Uncertainty in Global DAQ Shift (DELTAT_UN, nanoseconds)

(3 x 2 = 6 in Total)

The set of module-specific parameters are:

• Pixel Masking Probability
• Isolated Hit ToT Upper Cut

The set of intrinsic parameters (non-experimental) in analysis:

• Size Width Cut [:= 1] (PXR)
• Size Height Cut [:= 1] (PXR)
• Effective Low Charge Width Cut [:= 1] (PXR)
• Effective Low Charge Height Cut [:= 1] (PXR)
• Effective High Charge Width Cut [:= 1] (PXR)
• Effective High Charge Height Cut [:= 1] (PXR)
• Metric Cut [:= 1] (C)

Back of the Envelope Calculations

Modelling the RD53B-CMS Readout Chip (CROC)

Basic Schematic of the Analog Front End

Modelling Time Walk

Modelling Time over Threshold (Analog)

Modelling Digitization of Time over Threshold

Modelling Pixel Masking

Modelling Noisy Pixels

Modelling Isolated Hit Removal

Validation with Laboratory Data

Engine

Structure of the CMSSW Data

Simulating CMSSW Events in Allpix Squared

Clustering Algorithm & Classes

(Definition) A cluster is a group of pixel hits which, for every two pixels in the group, (α,β) and (γ,δ), we have:

|| α - γ + δ - β || + || α + γ - β - δ || ≤ 2 × METRIC_CUT,

i.e. a rotated (by 45 degrees) L1 metric, which is consistent with how CMSSW performs clustering.

Pixel Hit Reconstruction Algorithm

Validation Results with CMSSW

Git Repository, Installation and Use

Results

Energy Deposition Distributions

Out of Time Hits / Clusters (OOR/C)

Residuals

Charge Resolution per CROC Mode

Efficiency