Physics for Particle Detectors and Particle Detectors for Physics: Timing Performance of Semiconductor Detectors with Internal Gain and Constraints on ... of the Higgs Boson (Springer Theses)

✍ Scribed by Philipp Windischhofer

• Publisher: Springer
• Year: 2023
• Tongue: English
• Leaves: 243
• Category: Library

✦ Synopsis

Experimental particle physics is a science of many scales. A large number of physical processes spanning energies from meV to TeV must be understood for modern collider experiments to be designed, built, and conducted successfully. This thesis contributes to the understanding of phenomena across this entire dynamic range. The first half of this document studies aspects of low-energy physics that govern the operation of particle detectors, limit their performance, and guide the development of novel instrumentation. To formalise these aspects, classical electrodynamics is used to derive a general description of the formation of electrical signals in detectors, and ideas from quantum mechanics are applied to the study of charge avalanche amplification in semiconductors. These results lead to a comprehensive analytical characterisation of the time resolution and the efficiency of single-photon avalanche diodes, and isolate the most important design variables. They also reveal the applicability of these devices in precision timing detectors for charged particles, which is experimentally verified in a high-energy hadron beam. Large detector systems at hadron colliders probe fundamental physics at the energy frontier. In the second half, data collected with the ATLAS detector during Run 2 of the Large Hadron Collider are used to measure the cross-section for the production of a Higgs boson together with an electroweak boson as a function of the kinematic scale of the process. This measurement provides the finest granularity available to date for this process. It is highly informative of the structure of interactions beyond the direct kinematic reach of the experiment, and new limits are set on the couplings of such interactions within an effective field theory.

✦ Table of Contents

Supervisor’s Foreword
Abstract
Acknowledgements
Contents
1 Introduction
Part I Physics for Particle Detectors
2 The Formation of Electrical Signals in Particle Detectors
2.1 Reciprocity Relations in Classical Electrodynamics
2.1.1 Lorentz Reciprocity
2.1.2 Network Reciprocity
2.1.3 Antenna Reciprocity
2.2 Signals Induced by a Moving Point Charge: The General Case
2.2.1 Induced Signals in the Presence of Background Fields
2.2.2 Processing and Filtering of the Detector Signal
2.3 Nonrelativistic Limit
2.3.1 Voltage Induced on Insulated Electrodes
2.3.2 Current Induced on Grounded Electrodes
2.3.3 Signals Induced on Electrodes Embedded in a Circuit
2.3.4 Detectors with Resistive Media
2.4 Applications and Examples
2.4.1 Signals Induced in Long Drift Tubes
2.4.2 Dipole Antennas as Particle Detectors
2.4.3 Radio Emissions of Showers Induced by Cosmic Rays
2.5 Conclusions
References
3 The Statistics of Electron-Hole Avalanches in Semiconductors
3.1 Avalanche Model and Assumptions
3.2 Avalanches as Stochastic Many-Body Systems
3.2.1 Avalanche Configurations and State Vectors
3.2.2 Observables and Expectation Values
3.2.3 Time Evolution
3.3 Avalanches in an Infinite Semiconductor with Constant Electric Field
3.3.1 Fock Space and Hamiltonian
3.3.2 Evolution of the Full State
3.3.3 Moments
3.3.4 Avalanches Driven by a Single Species
3.3.5 Time-Response Function
3.3.6 Time Resolution from Time-Response Function
3.3.7 Time Resolution for Large Thresholds
3.3.8 Summary
3.4 Avalanches in a Thin Semiconductor with Arbitrary Electric Field
3.4.1 Fock Space and Time-Evolution Operator
3.4.2 Average Development of the Avalanche
3.4.3 Development of Spatial Correlations and Fluctuations
3.4.4 Asymptotic Behaviour and Time Resolution
3.4.5 Summary
3.5 Avalanches in Silicon: Transport Parameters, Breakdown, and Time Scales
3.6 Quenching Dynamics and Large Avalanches
3.6.1 Adiabatic Model for Passive Quenching Without Space Charge
3.6.2 The Role of Space Charge
References
4 Time Resolution and Efficiency of Single-Photon Avalanche Diodes
4.1 Efficiency
4.2 Stochastic Initial Conditions
4.3 Photon Detection
4.3.1 Absorption in Conversion Layer
4.3.2 Absorption in Gain Layer
4.4 Charged Particle Detection
4.4.1 Interaction of Charged Particles with Matter
4.4.2 Efficiency
4.4.3 Time Resolution
4.5 Summary
References
5 In-Beam Performance of Single-Photon Avalanche Diodes
5.1 Device Information
5.2 Readout Electronics
5.3 Experimental Setup
5.3.1 Beam Telescope
5.3.2 Global Trigger Logic
5.3.3 SPAD Signal Acquisition
5.3.4 Online Data Processing and Slow Control
5.4 Data Collection and Beam Conditions
5.5 Offline Event Reconstruction and Signal Processing
5.6 Results
5.6.1 Breakdown Voltage
5.6.2 Dark-Count Rate
5.6.3 Charge Collection and Detector Response
5.6.4 Timing Characteristics and Time Resolution
5.7 Summary
References
Part II Particle Detectors for Physics
6 An Effective Theory of Fundamental Physics
6.1 A Reductionist's Guide to the Universe
6.2 The Standard Model as a Field Theory
6.3 Separation of Scales and Effective Descriptions
6.3.1 Phenomenology of Dimension-Five Operators
6.3.2 Phenomenology of Dimension-Six Operators
References
7 High-Energy Scattering Experiments
7.1 Kinematics of Proton-Proton Collisions
7.2 The Large Hadron Collider
7.3 The ATLAS Experiment
7.3.1 Inner Detector
7.3.2 Calorimetry
7.3.3 Muon Spectrometer
7.3.4 Trigger System
References
8 Measurement of WH and ZH Production in the Hrightarrowbbarb Channel
8.1 Simplified Template Cross-Sections
8.2 Event Samples
8.2.1 Data Sample
8.2.2 Samples of Simulated Events
8.3 Event Reconstruction and Physics Object Definition
8.3.1 Charged Leptons
8.3.2 Jets
8.3.3 Jet-Flavour Tagging
8.3.4 Missing Transverse Energy
8.4 Event Selection
8.5 Event Categorisation
8.6 Multivariate Discriminant
8.7 Statistical Model
8.7.1 Background Modelling
8.7.2 Systematic Uncertainties
8.7.3 Statistical Analysis
8.8 Results
8.8.1 Diboson Validation
8.8.2 Signal-Strength Measurements
8.8.3 STXS Measurements
8.9 Constraints on Effective Interactions
8.9.1 Selection of Operators
8.9.2 Parameterisation of Modifications to Observables
8.9.3 Modifications of Acceptance and Multivariate Discriminant
8.9.4 Statistical Model
8.9.5 Results
References
9 Combination of Measurements of VH Production in the Hrightarrowbbarb Channel
9.1 Measurement of Boosted VH Production
9.2 Combination Strategy
9.2.1 Overlap Removal
9.2.2 Statistical Model
9.3 Results
9.3.1 Signal-Strength Measurements
9.3.2 STXS Measurements
9.3.3 Constraints on Effective Interactions
References
10 Conclusions and Outlook
Appendix A The Statistics of Electron-Hole Avalanches in Semiconductors: Auxiliary Material
A.1 Commutation Relations
A.1.1 Ladder Operators
A.1.2 Number Operators
A.1.3 Translation Operators
A.2 Logarithmic Fluctuations at Late Times
A.3 Markov Avalanche Monte Carlo Simulation Model