Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Zeke Insepov Project Name: kinetic Division: MCS Project title: Kinetic Monte Carlo simulation of radiation defects evolution and thin film deposition Associated funding: RERTR AFCI Other Systems: Blue Gene, aniki Science: As a part of the continuing effort to study the microstructure evolution of Molybdenum (Mo) under irradiation of Xenon (Xe) Ions at different temperature regimes and different radiation doses, an on-lattice Kinetic Monte Carlo model is being built for that purpose. The first objective of this model is to investigate the bimodal gas bubble size distribution observed experimentally by simulating defects diffusion through the matrix during the so-called kinetic phase, in contrast to ballistic phase. The "ballistic phase" accounts for the creation of defects through cascade of collisions made by a primary knock-on atom (PKA), while the "kinetic phase", accounts for the diffusion-controlled dynamical evolution of such defects. The on-lattice model employs space discretization technique and hence allows the defect to exist only on a defined set of points in the space depending on the type of the defect. Normally, this set of points consists of certain interstitial sites, in addition to lattice sites. KMC algorithm is then used to simulate defects hops between these points. Understanding the mechanisms involved in defects diffusion process is so crucial, as different mechanisms,at the same temperature and defect population, could result in completely different behavior. The existence of thermally activated slipping systems in Mo, which can at finite temperature compete with the crowdion and <111> dumbbell diffusion mechanism, adds more complication to the simulation of interstitial diffusion. KMC gives the capability of isolating different mechanisms, in order to explore the contribution of individual mechanisms to a certain phenomenon. The first step focused on studying the embryonic stage (incubation and nucleation stage) of voids and followed by tracking the spatial arrangement and the void size distribution as a function of temperature and displacements per atom (dpa). The objective of this part is to investigate the possibility of void superlattice formation and the role played by hypothesized shadowing effect in this case. Project description: We will use the kinetic Monte Carlo and Metropolis Monte Carlo methods that were realized as a SPPARKS package at SANDIA Labs. SPPARKS is a parallel Monte Carlo code for on-lattice and off-lattice models that includes algorithms for kinetic Monte Carlo (KMC), rejection kinetic Monte Carlo (rKMC), and Metropolis Monte Carlo (MMC), coupling of this code with MD-Synchronous parallel kMC. The scaling properties of KMC solvers currently available in SPPARKS : linear search, O(N) tree search, O(logN) composition-rejection search, O(1) We plan to run 150-200 jobs of 256 cores x 5-10 hours. For validation and fortification of this KMC model, comparison with experimental results is needed. The in situ TEM study of Xe implantation in pure Mo, took place at ANL facilities, gives valuable data on Xe bubble size distribution in Mo, which can be used as a reference data to be compared with the results of this model. Accelerator experiments are planned to be conducted at Argonne IVEM and Atlas machines, to verify the simulation results. SPPARKS will run on any parallel machine that compiles C++ and supports the MPI message-passing library. This includes distributed- or shared-memory machines. We expect 4-5 users that will be working on this project. Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 250000 Q1: 50000 Q2: 75000 Q3: 50000 Q4: 75000 Justification: Thank You, The LCRC Accounts System