The statistics of electron-hole avalanches

Charge multiplication through avalanche processes is commonly employed in the detection of single photons or charged particles in high-energy physics and beyond. In this report, we provide a detailed discussion of the properties of avalanches driven by two species of charge carriers, e.g. electrons and holes in a semiconductor exposed to an electric field. We derive equations that describe the general case of avalanches developing in inhomogeneous electric fields and give their analytical solutions for constant fields. We discuss consequences for the time resolution achievable with detectors that operate above the breakdown limit, e.g. single-photon avalanche diodes (SPADs) and silicon photomultipliers (SiPMs). Our results also describe avalanches that achieve finite gain and are important for avalanche photodiodes (APDs) and low-gain avalanche detectors (LGADs)

Passive quenching, signal shapes, and space charge effects in SPADs and SiPMs

In this report we study the dynamics of passive quenching in a single-photon avalanche diode. Our discussion is based on a microscopic description of the electron-hole avalanche coupled to the equivalent circuit of the device, consisting of the quench resistor and the junction capacitance. Analytic expressions for the resulting signal shape are derived from this model for simple electric field configurations, and efficient numerical prescriptions are given for realistic device geometries. Space charge effects are included using simulations. They are shown to distort the signal shape, but alter neither its basic characteristics nor the underlying quenching mechanism

The Web Performance of Different Types of Online Insurance Providers – A Wake up Call to Traditional Insurance Providers

The skill of successfully utilizing the Internet as distribution channel for non-life insurance products is examined by comparing the web site usability of three different types of insurance providers from the UK. A longestablished, traditional insurance company is benchmarked with a pure online insurer and a groceries retailer that diversified into online insurance. The study is conducted from the consumer’s perspective by using expert evaluation techniques and a grounded theory approach. The findings suggest that the newer types of insurance providers outperform the traditional type and therefore represent a significant competitive threat to the insurance industry as we know it today. The theoretical findings suggest that frameworks for analysing web site usability are highly sensitive to context, and in the case of insurance services, appearance of the web site and assistance to the consumer while using the web site are evaluation criteria that are more important than expected and need to be included when analyzing non-life insurance web sites

Signals induced on electrodes by moving charges, a general theorem for Maxwell's equations based on Lorentz-reciprocity

We discuss a signal theorem for charged particle detectors where the finite propagation time of the electromagnetic waves produced by a moving charge cannot be neglected. While the original Ramo-Shockley theorem and related extensions are all based on electrostatic or quasi-electrostatic approximations, the theorem presented in this report is based on the full extent of Maxwell's equations and does account for all electrodynamic effects. It is therefore applicable to all devices that detect fields and radiation from charged particles

Hierarchical Neural Simulation-Based Inference Over Event Ensembles

When analyzing real-world data it is common to work with event ensembles, which comprise sets of observations that collectively constrain the parameters of an underlying model of interest. Such models often have a hierarchical structure, where "local" parameters impact individual events and "global" parameters influence the entire dataset. We introduce practical approaches for optimal dataset-wide probabilistic inference in cases where the likelihood is intractable, but simulations can be realized via forward modeling. We construct neural estimators for the likelihood(-ratio) or posterior and show that explicitly accounting for the model's hierarchical structure can lead to tighter parameter constraints. We ground our discussion using case studies from the physical sciences, focusing on examples from particle physics (particle collider data) and astrophysics (strong gravitational lensing observations).Comment: 10+4 pages, 5 figure

Hierarchical neural simulation-based inference over event ensembles

When analyzing real-world data it is common to work with event ensembles, which comprise sets of observations that collectively constrain the parameters of an underlying model of interest. Such models often have a hierarchical structure, where ``local'' parameters impact individual events and ``global'' parameters influence the entire dataset. We introduce practical approaches for frequentist and Bayesian dataset-wide probabilistic inference in cases where the likelihood is intractable, but simulations can be realized via a hierarchical forward model. We construct neural estimators for the likelihood(-ratio) or posterior and show that explicitly accounting for the model's hierarchical structure can lead to significantly tighter parameter constraints. We ground our discussion using case studies from the physical sciences, focusing on examples from particle physics and cosmology

LTCC and thick-film ceramic magnetic sensors for tokamak nuclear fusion

The present contribution gives an overview of our work on non-conventional magnetic coil sensors for diagnostics and plasma stability control of nuclear fusion experiments in tokamaks. Instead of wire wound around a core, these devices consist of printed conductor wire coils on ceramic substrates, and are based on LTCC (low-temperature co-fired ceramic) and thick-film technology, which allow creation of monolithic multilayer coils with excellent stability. For 3D sensing, an innovative modular design combining LTCC coils and an alumina base has been developed. Finally, the important aspects of integration, manufacturing, mounting and interconnection are discussed

Comparison of plasma endothelin levels between osteoporotic, osteopenic and normal subjects

BACKGROUND: It has been demonstrated that endothelins (ET) have significant roles in bone remodeling, metabolism and physiopathology of several bone diseases. We aimed to investigate if there was any difference between the plasma ET levels of osteoporotic patients and normals. METHODS: 86 patients (70 women and 16 men) with a mean age of 62.6 (ranges: 51–90) years were included in this study. Patients were divided into groups of osteoporosis, osteopenia and normal regarding reported T scores of DEXA evaluation according to the suggestions of World Health Organization. According to these criteria 19, 43 and 24 were normal, osteopenic and osteoporotic respectively. Then total plasma level of ET was measured in all patients with monoclonal antibody based sandwich immunoassay (EIA) method. One-way analysis of variance test was used to compare endothelin values between normals, osteopenics and osteoporotics. RESULTS: Endothelin total plasma level in patients was a mean of 98.36 ± 63.96, 100.92 ± 47.2 and 99.56 ± 56.6 pg/ml in osteoporotic, osteopenic and normal groups respectively. The difference between groups was not significant (p > 0.05). CONCLUSION: No significant differences in plasma ET levels among three groups of study participants could be detected in this study

Measurements of observables sensitive to colour reconnection in ¯ events with the ATLAS detector at √ = 13 TeV

A measurement of observables sensitive to effects of colour reconnection in top-quark pair-production events is presented using 139 fb−1 of 13 TeV proton–proton collision data collected by the ATLAS detector at the LHC. Events are selected by requiring exactly one isolated electron and one isolated muon with opposite charge and two or three jets, where exactly two jets are required to be b-tagged. For the selected events, measurements are presented for the charged-particle multiplicity, the scalar sum of the transverse momenta of the charged particles, and the same scalar sum in bins of charged-particle multiplicity. These observables are unfolded to the stable-particle level, thereby correcting for migration effects due to finite detector resolution, acceptance and efficiency effects. The particle-level measurements are compared with different colour reconnection models in Monte Carlo generators. These measurements disfavour some of the colour reconnection models and provide inputs to future optimisation of the parameters in Monte Carlo generators