The IMPACT (Integrated Map and Particle Accelerator Tracking) code was first developed under Computational Grand Challenge project in the mid 1990s [1]. It started as a three-dimensional (3D) data parallel particle-in-cell (PIC) code written in High Performance Fortran. The code used a split-operator based method to solve the Hamiltonian equations of motion. It contained linear transfer maps for drifts, quadrupole magnets and rf cavities. The space-charge forces were calculated using an FFT-based method with 3D open boundary conditions and longitudinal periodic boundary conditions. This code was completely rewritten in the late 1990s based on a message passing parallel programming paradigm using Fortran 90 and MPI following an object-oriented software design. This improved the code's scalability on large parallel computer systems and also gave the code better software maintainability and extensibility [2]. In the following years, under the SciDAC-1 accelerator project, the code was extended to include more accelerating and focusing elements such as DTL, CCL, superconducting linac, solenoid, dipole, multipoles, and others. Besides the original split-operator based integrator, a direct integration of Lorentz equations of motion using a leap-frog algorithm was also added to the IMPACT code to handle arbitrary external nonlinear fields. This integrator can read in 3D electromagnetic …

One of the next-generation power sources is the proton exchange membrane (PEM) fuel cell, which runs on pure hydrogen or hydrogen-rich reformate. At the heart of the PEM fuel cell is a membrane electrode assembly (MEA). The MEA is a laminate composed of electrode layers sandwiched between outer layers, fabricated from either carbon fiber or fabric and which control the diffusion of reactant gases, and the inner polymer mebrane. Hydrogen is oxidized at the anode to form protons, which migrate through the membrane and react with oxygen at the cathode to form water. In this type of fuel cell, platinum catalyzes the reactions at both electrodes. Realization of a future that includes ubiquitous use of hydrogen fuel cell-powered vehicles will be partially contingent on a process for recycling components of the fuel cell membrane electrode assemblies. In aggregate, the platinum used for the fuel cell will represent a large pool of this precious metal, and the efficient recycling of Pt from MEA's will be a cost-enabling factor for success of this technology. Care must be taken in the reclamation process because of the presence of fluoropolymers in the MEA. While Pt is normally recovered with high yield, the combustion process …

The IMPACT-T code is a parallel three-dimensional quasi-static beam dynamics code for modeling high brightness beams in photoinjectors and RF linacs. Developed under the US DOE Scientific Discovery through Advanced Computing (SciDAC) program, it includes several key features including a self-consistent calculation of 3D space-charge forces using a shifted and integrated Green function method, multiple energy bins for beams with large energy spread, and models for treating RF standing wave and traveling wave structures. In this paper, we report on recent improvements to the IMPACT-T code including modeling traveling wave structures, short-range transverse and longitudinal wakefields, and longitudinal coherent synchrotron radiation through bending magnets.

All too often we rely on Monte Carlo simulations withoutworrying too much about basic physics. It is possible to start with avery simple calorimeter (a big cylinder) and learn the functional form ofpi e by aninduction argument. Monte Carlo simulations provide sanitychecks and constants. A power-law functional form describes test beamresults surprisingly well. The prediction that calorimeters responddifferently to protons and pions of the same energy was unexpected. Theeffect was later demonstrated by the CMS forward calorimeter group, usingthe most noncompensating calorimeter ever built. Calorimeter resolutionis dominated by fluctuations in piz production and the energy deposit byneutrons. The DREAM collaboration has recently used a dual readoutcalorimeter to eliminate the first of these. Ultimate resolution dependson measuring neutrons on an event-by-event basis as well.

Article on the solubility of anthracene in binary diisopropyl ether + alkane solvent mixtures at 298.15 K.