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he gisaxs technique is an X ray scattering one, worldly developing in many scientific fields like biology, material science or soft condense matter used to study precipitates of nanometric size. This technique derives from the classical Saxs and Asaxs ones and needs special software to be analyzed. Theory is well known (see for example gisaxs.de or cornell.edu sites) and will be skipped here. Few softwares are available to extract significant information, each one having advantages and drawbacks but none to our knowledge allowing to study all three techniques in the same application.
This is why I choose to write Actionjava.
ctionjava is a software written in java, thus « independent » of the OS used to analyze saxs/asaxs(resonant)/gisaxs 2D data.
It runs with the corresponding « JVM » (Java Virtual Machine) installed. Its main goal is to deliver a flexible soft with many tools to satisfy different saxs communities, using unified menus, each one having an on line help (in French or English as chosen at the start). A menu can be inserted in a macro list of menus, macro which can be executed automatically after loading a file. The result of a calculation may be automatically input in different menus (inheritance). Since the macro can be applied to a large set of files, with creation of a pdf output file where results and images will be saved, it is very easy to correct and analyze lengthy experiments.
The examples are divided into 3 categories: Saxs, Asaxs and Gisaxs. The first set proposes a classical Guinier study of a GP zones kinetic, when the second (Beyond Guinier) shows a reconstruction of one of the spectra, with a fit of the different parameters entering in the form, organization and size distribution of the precipitates.
In the Asaxs examples (in fact Agisaxs), is studied a complex sample of nano precipitates. This sample was created by sputtering successively Pt and Co on a Si substrate (ref: P. Andreazza & al., European Physical Journal.-Special Topics, 2012, 208: 231-244) and illustrates the power of the anomalous or resonant effect on the study of such complex objects. It implies that the gisaxs spectrum was recorded at different photon energies, in order to modify the atomic scattering factor of Pt. In the first one (Asaxs Selection), is shown how to select the ‘good’ spectra, and in the second one (Asaxs Results) are extracted the contributions of respectively the Pt atoms and Co ones to the whole spectrum. The result implies that the Co atoms do not mix with the Pt precipitates formed by the first sputtering (alloying hypothesis) but instead covers them (core_shell hypothesis).
In the third set of examples, the Actionjava software demonstrates all its power and efficiency. Firstly (Gisaxs Fit 1), it is applied to the Pt contribution previously obtained: a fit is performed under the DWBA assumption to determine the different parameters of the Pt part of the precipitates. Then in the second part (Gisaxs Fit 2) a complete core shell model is applied which allows to extract every precipitates parameters.
Without the anomalous study, and due to the number of parameters entering in such complex models, it would be difficult to believe on the outputs of such optimizations: it is always possible to fit an elephant with enough parameters!
- JVM version 1.7.0 or later, can be downloaded from Oracle
- 768 Mo of contiguous memory