SANS group mission
Screen shot of the SliceView prototype.
Introduction
The SANS group at the University of Tennessee is part of the DANSE project, an NSF-funded 1.2 million dollar project to develop software to enable new science to be performed with neutron scattering experiments. The mission of our group is to extend the SANS data analysis capabilities by developing new tools for our users.In order to better serve our users, our group is committed to involving the community as early as possible in the software engineering process. Below you will find analysis areas we are interested in and applications we plan to provide. If you have ideas, requests, please feel free to contact us. Contribution are also welcome.
The path forward
The DANSE/SANS group will provide analysis functionality through three applications. Those applications will be incrementally developed throughout the life of the project. The computational functionality will be developed separately from the applications. The following is a list of the main areas of development:- Basic modeling
We will provide basic 1D and 2D models for SANS. Models for specific systems (like rods, spheres, core-shell cylinder) will be made available, in addition to system-independent models for standard fitting (like Guinier fitting) or magnetic analysis.Status: 1D and 2D models for some systems are available.
- Simulation of real-space systems
We will provide functionality to simulate systems made of basic shapes arranged in real-space. The scattering intensity will be calculated for those systems, both for oriented systems (2D scattering intensity) and rotationally averaged systems (1D scattering intensity).Status: 1D simulation available, 2D simulation in progress.
- Interface with community software
The IGOR platform is the SANS community standard for data analysis. DANSE will provide an interface to IGOR to facilitate the integration and use of the analysis functionality we are developing. This will allow early access to DANSE code will applications are being developed.Status: 2D modeling is available as a prototype XOPS.
- Inversion of P(r)
- Ab initio modeling
- Experimental planning and optimization
- MC simulation
- Series analysis and simultaneous fitting
- Constrained fitting
As the computational functionality becomes available, we will provide prototype applications for our users to try out. Those prototypes will enable us to gather requirements from the community and better plan for our releases. The following is a list of the applications we will provide:
- Prototype: Simulation of real-space systems
This prototype was made available to a selected community of testers in mid-2007 to investigate the construction of real-space systems from basic shapes. The user interface is built around an empty 3D canvas on which users can place objects. P(r) and I(q) are then simulated for the systems represented on the canvas.This prototype has served its requirement gathering purpose and was retired during the summer of 2007. A new version called SimView has been available since March 2008.
Status: released
- Prototype: 2D modeling [SliceView]
SliceView is a prototype that allows users to compare oriented models to NIST-compatible data. Users can select slices of the 2D image and compare them to data. Polydispersity and averaging over angular distributions is also available.Status: released
- Prototype: model-independent fitting
This prototype will allow users to fit 1D scattering intensity distributions to system-independent models. The most common are Guinier analysis, Porod analysis and power-law fits. This prototype will correspond to a new major release of SliceView.Status: first planned release early to mid-2008
- Prototype: Experiment planning tools
Status: first planned release late 2009 - Application: Model fitting analysis
This application will allow the user to specify objects in a 3D modeling space, either rotationally averaged or partially oriented, and produce 2D and 1D scattering patterns. The application will provide models with analytical functions to produce the scattering patterns. Optimization against 1D or 2D reduced data will include standard parameter optimizations as well as constrained conformational searches.Status: release planned for mid-2009
- Application: Model-independent analysis
This application will read 1D or 2D reduced SANS data and allow various manipulations by the user, including simple math, inversion to the pair density distribution function [P(R)], so called ab-initio fitting, and include simple linear analysis, peak shape analysis, correlation length analysis, etc. Batch mode operation for parametric analysis will also be included.Status: release planned for early 2010
- Application: Experiment planning tools
Given source and instrument parameters, this application will allow simulation of the raw data collected as a function of experimental parameters (e.g. time, sample thickness, and size) including some system dependent background such as incoherent scattering from the sample. This will make use of the models developed for the previous applications and convolute them with the instrument specific parameters (e.g. beam flux).Status: release planned for early 2011
