In the presented example, seven models are split into three groups (indicated by the dashed line), whereby there are three models in the first group while the second and the third groups contain two models each. The program suggests the optimal way of splitting multiple models into groups based on the distance criteria (either NSD or r.m.s.d.). ( a) Clustering of multiple models by DAMCLUST. Schematic representation of some new algorithms introduced in ATSAS 2.4. The web-related developments, including a user discussion forum and a widened online access to run ATSAS programs, are also presented.ĪTSAS biological macromolecules computer programs data analysis isotropic scattering small-angle scattering structural modelling.
#Small angle neutron scattering resolution calculator mac#
The new ATSAS release includes installers for current major platforms (Windows, Linux and Mac OSX) and provides improved indexed user documentation. They include (i) multiplatform data manipulation and display tools, (ii) programs for automated data processing and calculation of overall parameters, (iii) improved usage of high- and low-resolution models from other structural methods, (iv) new algorithms to build three-dimensional models from weakly interacting oligomeric systems and complexes, and (v) enhanced tools to analyse data from mixtures and flexible systems. The techniques developed to calculate I(q) for the Menger sponge and the fractal jack can also be employed to find the small-angle scattering from other nonrandom (regular) fractals.New developments in the program package ATSAS (version 2.4) for the processing and analysis of isotropic small-angle X-ray and neutron scattering data are described. Thus I(q) for the two nonrandom fractals does not appear to approach the simple power-law scattering proportional to q − D which is characteristic of the small-angle scattering from random fractals. Numerical calculations of I(q) provide no evidence that the maxima and minima are damped and die out as q becomes larger. The number of maxima within a group becomes greater as k increases. Groups of maxima are found at q = 3 k q 1, where k is a positive integer greater than 1. The first maximum for q>0 is a single peak located at q= q 1. For large qa the monotonic decay is proportional to q − D, where D is the fractal dimension. The calculations show that I(q) is a monotonically decreasing function on which maxima and minima are superimposed. The scattered intensity I(q) can be expressed as a function of qa, where q=4π λ − 1sin(theta/2) λ is the scattered wavelength theta is the scattering angle, and a is the edge of the cube which is the starting approximant to the fractal. The scatterers are assumed to be systems of independently scattering, randomly oriented identical nonrandom fractals constructed from a material with uniform density. The intensity of the small-angle x-ray or neutron scattering has been calculated for two nonrandom (regular) fractals: the Menger sponge and a related fractal, called the fractal jack (a form similar to the metal six-pointed object used in the American children’s game).