Fracture initiation in Viscoelastic Solids

The subject of this paper is to derive generalized analytical expressions to predict fracture in viscoelastic polymer materials. To aid in understanding behavioral characteristics of viscoelastic materials, a basic background of viscoelastic models and their responses are presented and briefly discussed. Fracture from two types of cracks are considered; the first 1s a penny-shaped crack in a three-dimensional solid and the second is a crack the thickness of the material in a two-dimensional solid. Except for the constants, the same equations describe fracture in both 2-D and 3-D solids. The fracture equations were developed using expressions from Sneddon, Wnuk, Griffith and the theory of elasticity. (See more in text

Single Track Performance of the Inner Detector New Track Reconstruction (NEWT)

In a previous series of documents we have presented the new ATLAS track reconstruction chain (NEWT) and several of the involved components. It has become the default reconstruction application for the Inner Detector. However, a large scale validation of the reconstruction performance in both efficiency and track resolutions has not been given yet. This documents presents the results of a systematic single track validation of the new track reconstruction and puts it in comparison with results obtained with different reconstruction applications

Concepts, Design and Implementation of the ATLAS New Tracking (NEWT)

The track reconstruction of modern high energy physics experiments is a very complex task that puts stringent requirements onto the software realisation. The ATLAS track reconstruction software has been in the past dominated by a collection of individual packages, each of which incorporating a different intrinsic event data model, different data flow sequences and calibration data. Invoked by the Final Report of the Reconstruction Task Force, the ATLAS track reconstruction has undergone a major design revolution to ensure maintainability during the long lifetime of the ATLAS experiment and the flexibility needed for the startup phase. The entire software chain has been re-organised in modular components and a common Event Data Model has been deployed during the last three years. A complete new track reconstruction that concentrates on common tools aimed to be used by both ATLAS tracking devices, the Inner Detector and the Muon System, has been established. It has been already used during many large scale tests with data from Monte Carlo simulation and from detector commissioning projects such as the combined test beam 2004 and cosmic ray events. This document concentrates on the technical and conceptual details of the newly developed track reconstruction, also known as New Tracking

Updates of the ATLAS Tracking Event Data Model (Release 13)

In a previous document we have presented the ATLAS tracking Event Data Model (EDM) that has been developed during the recent restructuring of the ATLAS offline track reconstruction. The tracking EDM has become a cornerstone of the new modular track reconstruction algorithms of both tracking devices of the ATLAS detector, the Inner Detector and the Muon System. Recently, some components have undergone yet another design evolution targeted at completing missing modules and at establishing anticipated functionality for the startup of the ATLAS experiment. One particular aspect of the EDM is that is does not only have to fulfill the requirements of today's algorithmic modules, but has to provide the flexibility for future developments. This document is based on ATLAS software release 13.0.0

ATLAS Tracking Event Data Model

In this report the event data model (EDM) relevant for tracking in the ATLAS experiment is presented. The core component of the tracking EDM is a common track object which is suited to describe tracks in the innermost tracking sub-detectors and in the muon detectors in offline as well as online reconstruction. The design of the EDM was driven by a demand for modularity and extensibility while taking into account the different requirements of the clients. The structure of the track object and the representation of the tracking-relevant information are described in detail

Refitting of combined inner detector and muon spectrometer tracks from Monte Carlo samples by using the Kalman fitter and the STEP algorithm in the ATLAS experiment

In this paper we refit combined muon tracks using the Kalman fitter and the simultaneous track and error propagation (STEP) algorithm of the ATLAS tracking software. The muon tracks are simulated by GEANT4 in the full detector description, reconstructed by MUID, and refitted by the Kalman fitter in the ATLAS TrackingGeometry. The relative transverse momentum resolution of the refitted tracks is compared to the resolution of the refits done by the global chi-square track fitter, along with the resolution found by the MUID and STACO muon combination algorithms. Reconstructed invariant masses are compared in a similar way

Pseudo‐ Para ‐Substituted [2.2]Paracyclophanes for Hole Transport in Perovskite Solar Cells

2,2′,7,7′-Tetrakis(N,N-di-p-methoxyphenylamine)−9,9′-spirobifluorene (spiro-OMeTAD) is the prevalent hole transport layer in perovskite solar cells (PSCs) with regular device architecture. Yet, its spirobifluorene core and multistep synthesis make it rather expensive. For the further technological success of PSCs, novel scalable and inexpensive alternative hole transport layers are needed. Herein, a study of the structure-property relations of pseudo-para-substituted [2.2]paracyclophanes is presented. Eight different hole transport materials are synthesized via double CH activation, eliminating metal-containing substituents for cross-coupling reactions. The ionization potentials (IPs) of the disubstituted paracyclophanes (DiPCPs) are examined by photoelectron spectroscopy in air, cyclic voltammetry and theoretical calculations. Through variation of donor groups and π-linkers, IPs that span a range from 5.14 to 5.86 eV are achieved, demonstrating high customizability. From the eight novel materials, five showed good solubility and are implemented into PSCs. The solar cells with a hole transport layer of undoped 4,16-di(4-(2-thienyl)-N,N-bis(4-methoxyphenyl)aniline)[2.2]paracyclophane (DiPCP-2) exhibit a power conversion efficiency of 12.7% ± 0.4%. The facile synthesis of DiPCP-2 enables an estimated cost reduction by two thirds compared to spiro-OMeTAD

ATLAS Inner Detector Event Data Model

The data model for event reconstruction (EDM) in the Inner Detector of the ATLAS experiment is presented. Different data classes represent evolving stages in the reconstruction data flow, and specific derived classes exist for the sub-detectors. The Inner Detector EDM also extends the data model for common tracking in ATLAS and is integrated into the modular design of the ATLAS high-level trigger and off-line software

The Algorithm Steering and Trigger Decision mechanism of the ATLAS High Level Trigger

Given the extremely high output rate foreseen at LHC and the general-purpose nature of ATLAS experiment, an efficient and flexible way to select events in the High Level Trigger is needed. An extremely flexible solution is proposed that allows for early rejection of unwanted events and an easily configurable way to choose algorithms and to specify the criteria for trigger decisions. It is implemented in the standard ATLAS object-oriented software framework, Athena. The early rejection is achieved by breaking the decision process down into sequential steps. The configuration of each step defines sequences of algorithms which should be used to process the data, and 'trigger menus' that define which physics signatures must be satisfied to continue on to the next step, and ultimately to accept the event. A navigation system has been built on top of the standard Athena transient store (StoreGate) to link the event data together in a tree-like structure. This is fundamental to the seeding mechanism, by which data from one step is presented to the next. The design makes it straightforward to utilize existing off-line reconstruction data classes and algorithms when they are suitableComment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 8 pages, PDF, PSN TUGT00

ATLAS Detector Paper Back-Up Note: Electrons and Photons

This is the supporting note to the ATLAS Detector paper for electron and photon reconstruction with the Inner Detector. It describes the software used to produce the results presented in the ATLAS Detector paper