Geant4 is a software toolkit for the simulation of the passage of particles through matter. It is used by a large number of experiments and projects in a variety of application domains, including high energy physics, astrophysics and space science, medical physics and radiation protection. Over the past several years, major changes have been made to the toolkit in order to accommodate the needs of these user communities, and to efficiently exploit the growth of computing power made available by advances in technology. The adaptation of Geant4 to multithreading, advances in physics, detector modeling and visualization, extensions to the toolkit, including biasing and reverse Monte Carlo, and tools for physics and release validation are discussed here.

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Recent developments in GEANT4

There is increased recognition by the world’s scientific, industrial, and political communities that the concentrations of greenhouse gases in the earth’s
atmosphere, particularly CO_2, are increasing. For
example, recent studies of Antarctic ice cores to
depths of over 3600 m, spanning over 420 000 years,
indicate an 80 ppm increase in atmospheric CO_2 in
the past 200 years (with most of this increase
occurring in the past 50 years) compared to the
previous 80 ppm increase that required 10 000 years.2
The 160 nation Framework Convention for Climate
Change (FCCC) in Kyoto focused world attention on
possible links between CO2 and future climate change
and active discussion of these issues continues.3 In
the United States, the PCAST report4 “Federal
Energy Research and Development for the Challenges
of the Twenty First Century” focused attention
on the growing worldwide demand for energy and the
need to move away from current fossil fuel utilization.
According to the U.S. DOE Energy Information
Administration,5 carbon emission from the transportation
(air, ground, sea), industrial (heavy manufacturing,
agriculture, construction, mining, chemicals,
petroleum), buildings (internal heating, cooling, lighting),
and electrical (power generation) sectors of the
World economy amounted to ca. 1823 million metric
tons (MMT) in 1990, with an estimated increase to
2466 MMT in 2008-2012 (Table 1).

Catalysis Research of Relevance to Carbon Management: Progress, Challenges, and Opportunities

Supported Catalysts Weiting Yu,† Marc D. Porosoff,† and Jingguang G. Chen*,†,‡,§ †Catalysis Center for Energy Innovation, Department of Chemical and Bimolecular Engineering, University of Delaware, Newark, Delaware 19716, United States ‡Department of Chemical Engineering, Columbia University, New York, New York 10027, United States Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, United States

Review of Pt-based bimetallic catalysis: from model surfaces to supported catalysts.

Size dependence of nanostructures: Impact of bond order deficiency

Physical and chemical properties of bimetallic surfaces

Science communication is a growing area of practice and research. During the past two decades, the number of activities, courses, and practitioners has steadily increased. But what actually is science communication? In what ways is it different to public awareness of science, public understanding of science, scientific culture, and scientific literacy? The authors review the literature to draw together a comprehensive set of definitions for these related terms. A unifying structure is presented and a contemporary definition of science communication positioned within this framework. Science communication (SciCom) is defined as the use of appropriate skills, media, activities, and dialogue to produce one or more of the following personal responses to science (the AEIOU vowel analogy): Awareness, Enjoyment, Interest, Opinion-forming, and Understanding. The definition provides an outcomes-type view of science communication, and provides the foundations for further research and evaluation.

Science Communication: A Contemporary Definition

Despite a wealth of theoretical and experimental research on interatomic potentials, there has been only limited guidance on how well each compares to all others. In this report, many popular theoretical potentials are compared to a large range of experimental potentials to gauge the accuracy of the various theoretical models. From this comparison it is found that the “ Universal Potential” of Biersack and Ziegler agrees best with the available measurements. Correction factors are derived which give similar agreement for the other potentials, but some systematic deviations still persist at the low or high energy end for most other potentials, as demonstrated for the Moliere potential.

Comparison of theoretical and empirical interatomic potentials

A detailed survey of the currently available data for the energy loss straggling of hydrogen, helium and heavy ions in matter has been undertaken. An empirical formula based on Chu's calculation has been obtained for the energy loss straggling of hydrogen ions. Using this formula with the effective charge and the scaling of straggling, similar to the scaling of stopping powers, good estimates have been made for He and heavy ions. The empirical formulae represent the available data accurately and permit reliable estimates for combinations of projectile and target where currently no data is available.

Empirical formulae for energy loss straggling of ions in matter

I Introduction.- 1 Solid Surfaces, Their Structure and Composition.- 2 UHV Basics.- II Techniques.- 3 Electron Microscope Techniques for Surface Characterization.- 4 Sputter Depth Profiling.- 5 SIMS - Secondary Ion Mass Spectrometry.- 6 Auger Electron Spectroscopy and Microscopy - Techniques and Applications.- 7 X-Ray Photoelectron Spectroscopy.- 8 Vibrational Spectroscopy of Surfaces.- 9 Rutherford Backscattering Spectrometry and Nuclear Reaction Analysis.- 10 Materials Characterization by Scanned Probe Analysis.- 11 Low Energy Ion Scattering.- 12 Reflection High Energy Electron Diffraction.- 13 Low Energy Electron Diffraction.- 14 Ultraviolet Photoelectron Spectroscopy of Solids.- 15 EXAFS.- III Processes and Applications.- 16 Minerals, Ceramics and Glasses.- 17 Characterization of Catalysts by Surface Analysis.- 18 Application to Semiconductor Devices.- 19 Characterisation of Oxidised Surfaces.- 20 Coated Steel.- 21 Thin Film Analysis.- 22 Identification of Adsorbed Species.- 23 Surface Analysis of Polymers.- 24 Glow Discharge Optical Emission Spectrometry.- IV Appendix.- Acronyms Used in Surface and Thin Film Analysis.- Surface Science Bibliography.

D.J. O'Connor

Papers

Science Communication: A Contemporary Definition

Comparison of theoretical and empirical interatomic potentials

Empirical formulae for energy loss straggling of ions in matter

Surface analysis methods in materials science

Melting of al surfaces