Andrea Dotti

A model for the interaction of high-energy particles in straight and bent crystals implemented in Geant4

A model for the simulation of orientational effects in straight and bent periodic atomic structures is presented. The continuum potential approximation has been adopted. The model allows the manipulation of particle trajectories by means of straight and bent crystals and the scaling of the cross sections of hadronic and electromagnetic processes for channeled particles. Based on such a model, an extension of the Geant4 toolkit has been developed. The code has been validated against data from channeling experiments carried out at CERN.

Explorations of the viability of ARM and Xeon Phi for physics processing

We report on our investigations into the viability of the ARM processor and the Intel Xeon Phi co-processor for scientic computing. We describe our experience porting software to these processors and running benchmarks using real physics applications to explore the potential of these processors for production physics processing.

The Geant4 Physics Validation Repository

The Geant4 collaboration regularly performs validation and regression tests. The results are stored in a central repository and can be easily accessed via a web application. In this article we describe the Geant4 physics validation repository which consists of a relational database storing experimental data and Geant4 test results, a java API and a web application. Lastly, the functionality of these components and the technology choices we made are also described

Use of checkpoint-restart for complex HEP software on traditional architectures and Intel MIC

Process checkpoint-restart is a technology with great potential for use in HEP workflows. Use cases include debugging, reducing the startup time of applications both in offline batch jobs and the High Level Trigger, permitting job preemption in environments where spare CPU cycles are being used opportunistically and efficient scheduling of a mix of multicore and single-threaded jobs. We report on tests of checkpoint-restart technology using CMS software, Geant4-MT (multi-threaded Geant4), and the DMTCP (Distributed Multithreaded Checkpointing) package. We analyze both single- and multi-threaded applications and test on both standard Intel x86 architectures and on Intel MIC. The tests with multi-threaded applications on Intel MIC are used to consider scalability and performance. These are considered an indicator of what the future may hold for many-core computing.

GPU Acceleration of Monte Carlo Simulation at the Cellular and DNA Levels

Geant4-DNA is an extension of the general purpose Geant4 Monte Carlo simulation toolkit. It can simulate particle-matter physical interactions down to very low energies in liquid water. The simulation in that energy scale needs enormous computing time since it simulates all physical interactions following a discrete approach. This work presents the implementation of the physics processes/models of the Geant4-DNA extension in GPU architecture. We observed impressive performance gain with the same physics accuracy as existing methods.

Multi-threaded Geant4 on the Xeon-Phi with complex high-energy physics geometry

To study the performance of multi-threaded Geant4 for high-energy physics experiments, an application has been developed which generalizes and extends previous work. A highly-complex detector geometry is used for benchmarking on an Intel Xeon Phi coprocessor. In addition, an implementation of parallel I/O based on Intel SCIF and ROOT technologies is incorporated and studied.

arXiv : HEP Software Foundation Community White Paper Working Group - Detector Simulation

A working group on detector simulation was formed as part of the high-energy physics (HEP) Software Foundations initiative to prepare a Community White Paper that describes the main software challenges and opportunities to be faced in the HEP field over the next decade. The working group met over a period of several months in order to review the current status of the Full and Fast simulation applications of HEP experiments and the improvements that will need to be made in order to meet the goals of future HEP experimental programmes. The scope of the topics covered includes the main components of a HEP simulation application, such as MC truth handling, geometry modeling, particle propagation in materials and fields, physics modeling of the interactions of particles with matter, the treatment of pileup and other backgrounds, as well as signal processing and digitisation. The resulting work programme described in this document focuses on the need to improve both the software performance and the physics of detector simulation. The goals are to increase the accuracy of the physics models and expand their applicability to future physics programmes, while achieving large factors in computing performance gains consistent with projections on available computing resources.

DoSSiER: Database of scientific simulation and experimental results

\abstract{The Geant4, GeantV and GENIE collaborations regularly perform validation and regression tests for simulation results. DoSSiER ({\bf D}atabase of {\bf S}cientific {\bf Si}mulation and {\bf E}xperimental {\bf R}esults) is being developed as a central repository to store the simulation results as well as the experimental data used for validation. DoSSiER can be easily accessed via a web application. In addition, a web service allows for programmatic access to the repository to extract records in json or xml exchange formats. In this article, we describe the functionality and the current status of various components of DoSSiER as well as the technology choices we made.}

Software Aspects of the Geant4 Validation Repository

The Geant4, GeantV and GENIE collaborations regularly perform validation and regression tests for simulation results. DoSSiER (Database of Scientific Simulation and Experimental Results) is being developed as a central repository to store the simulation results as well as the experimental data used for validation. DoSSiER is easily accessible via a web application. In addition, a web service allows for programmatic access to the repository to extract records in JSON or XML exchange formats. In this article, we describe the functionality and the current status of various components of DoSSiER as well as the technology choices we made.

Extending Geant4 Parallelism with external libraries (MPI, TBB) and its use on HPC resources

The emergence of multi- and many-core processors has been a well-established trend in the chip-making industry during the past decade. While this paradigm guarantees the continued increase of CPU performance, it requires some adaptation of existing code in order to better utilize these architectures.