Monte Carlo simulations of quantum systems on massively parallel supercomputers

1993 ◽  
Vol 7 (6) ◽  
pp. 687 ◽  
Author(s):  
Hong Q. Ding
Author(s):  
A. D. Romig ◽  
J. R. Michael ◽  
S. J. Plimpton

Monte Carlo electron trajectory simulations have been adapted to run on massively parallel supercomputers. An nCUBE2 parallel supercomputer with 1024 processors has been used in these studies. The advantage of the parallel architecture is the great increase in computational speed and the fact that few changes in the standard serial Monte Carlo algorithms are required. The temporal performance of the massively parallel Monte Carlo electron trajectory simulation run on 1024 nodes has been compared with Monte Carlo codes run on other types of supercomputers (CRAY-YMP). It was found to be as much as 100 times faster than the CRAY-YMP and over 2000 times faster than a VAX 785. This increase in computational speed allows the exploration of problems, in particular those involving small probability events, which are not normally amenable to solution by traditional serial Monte Carlo simulations due tothe time intensive nature of the calculations. For example, the calculation of 1,000,000 electrons at 100 kV through a thin foil takes about 6 seconds on the nCUBE.


2017 ◽  
Vol 92 (6) ◽  
pp. 063001 ◽  
Author(s):  
Noritaka Shimizu ◽  
Takashi Abe ◽  
Michio Honma ◽  
Takaharu Otsuka ◽  
Tomoaki Togashi ◽  
...  

Author(s):  
Matthew T. Johnson ◽  
Ian M. Anderson ◽  
Jim Bentley ◽  
C. Barry Carter

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.


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