- users - SasView Mailing Lists

SasView Issues on macOS
by James Crake-Merani - STFC UKRI 03 Nov '26

03 Nov '26

Dear SasView users, An issue regarding SasView 6.2.0 has been identified with the latest versions of macOS, where SasView experiences unpredictable behaviour which often results in crashes. This issue has specifically been reported on macOS 26.7.2, and 27.0.1. It is related to the version of QT that we use. A newer QT version will be packaged with 6.2.1. Under our testing, we believe it resolves this issue, but until that release it will still affect 6.2.0. While 6.2.1 is scheduled to release after the contributor camp, we recognise that this issue will be affecting users now on macOS. As a temporary workaround, we recommend using the PyPi distribution of SasView for those affected. If you have uv<https://docs.astral.sh/uv/getting-started/installation/> installed, the easiest thing to do is run the follow command in the terminal. uvx sasview This will automatically install SasView 6.2.0 to a Python environment, alongside the latest versions of all the dependencies. Furthermore, there are alternatives instructions available in the README file of our Github repository<https://github.com/SasView/sasview> on how to install SasView via pip. We apologise for any inconvenience caused by this. An announcement will be made to this mailing list when 6.2.1 is released. In the meantime, if you continue to experience any issues, please reply to this mailing list, or create an issue on GitHub<https://github.com/SasView/sasview/issues>. Thanks, James. -- James Crake-Merani Graduate Research Software Engineer Science & Technology Facilities Council UK Research & Innovation

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Help shape SasView — share your views on AI and user support
by Wojtek Potrzebowski 17 Oct '26

17 Oct '26

Dear SasView users, We are gathering feedback on how people use SasView, where they turn for support, and what role AI assistants play in their small-angle scattering work. We would like to hear about your experiences through a short survey covering SasView and its related tools, how you find help, and the uses and limitations of AI in SAS analysis. Your responses will help us identify priorities for documentation, user support and potential new tools. Survey: https://docs.google.com/forms/d/e/1FAIpQLSf0SI28Avllz3vRuIayFO-Ocw-I0X33FyG… We would appreciate your responses before 1 November. Everyone’s perspective is welcome, whether you are new to SasView or an experienced user. Please complete the survey only once if you receive it through several mailing lists. Thank you for helping us improve SasView! Best regards, Wojtek On behalf of the SasView team

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SasView 6.2.0 released!
by Stephen King - STFC UKRI 13 Aug '26

13 Aug '26

Dear SasView Community, We are pleased to inform you that we have recently released an update to SasView, SasView 6.2.0, available as usual through the SasView website<https://www.sasview.org/>. This is a feature release which comes with a number of new features, general improvements, and bug fixes. For more information, please see the release notes<https://github.com/SasView/sasview/releases/tag/v6.2.0>. For those who prefer to build their installation from source (eg, Linux users), SasView is also available through Flatpak<https://flathub.org/apps/org.sasview.sasview>. We would also like to take this opportunity to remind you of the SasView Contributor Camp XV<https://www.sasview.org/2026-07-17-contributor-camp-15/> to be hosted by Charles University in Prague, Czechia, between November 3rd-9th, 2026. The final scope of the work at the Contributor Camp will be determined by the interests of those who attend, but known points of interest/focus this time include the General Scattering Calculator (making it more user-friendly while better supporting BioSAS needs), the Sasmodels package, and improving support for hard condensed matter and diffraction workflows. Please see the planning wiki at https://github.com/SasView/sasview/wiki/ContributorCampXV for more information. Thank you for your continued support! And, as ever, if you would like to get involved, please see https://www.sasview.org/contribute/ for further information. The SasView Collaboration

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SasView Size Distribution Model Convergence
by Jacob Barron 29 Jul '26

29 Jul '26

Hello, I am inquiring about the meaning of convergence from you size distribution model. I recently completed some SANS measurements on a low alloy steel and found the size dist model is not able to converge without increasing the weight factor. However the ChiSq value is quite low, almost one, and upon repeated fittings the resultant distributions are very similar, which is encouraging results and a distribution I would expect from these samples. [image: image.png] Increasing the weight factor to 1.5 allows the fit to converge. However I do notice that visually the curve fit worsens even though the ChiSq value is better. This convergence feels artificially forced to me, as my understanding is that this increases the error bars. I also notice this shifts the dominant size distribution slightly larger. Repeating this fit does not give a unique solution. [image: image.png] Would I be able to get an explanation on why the convergence matters here. I understand that the population is located on the boundary of the trust range, this is expected with this material, we are limited by the neutron wavelength in this case. Of course the reported volume fraction is to be taken with some uncertainty. Any help is appreciated. The file is attached, as is the raw data. Best regards, Jacob Barron, -- Jacob Barron, BSc, EIT PhD Candidate Materials Engineering University of Alberta

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Next Contributor Camp announced
by Paul Butler 17 Jul '26

17 Jul '26

Dear SasView community, It is with great pleasure that we announce the opening of registration for the XV SasView Contributor Camp to be held at Charles University in Prague, Nov 3-9 2026. This annual community event brings together members of the SAS community to work on improving the SasView tools, tutorials, and documentation that we all use. The final scope of the work is determined by the interests of those who attend but known points of interest/focus this time include the General Scattering Calculator (making it more user friendly while better supporting bioSAS needs), the sasmodels package, and improving support for hard condensed matter and diffraction workflows. Anyone interested in contributing to the SasView project (writing tutorials, documentation, coding, verifying the math/science, or undertaking sys admin tasks, etc) is welcome, even encouraged, to join. See the link below for the latest planning. This is an opportunity to come together to work on our common issues. The camp planning page can be found at: https://github.com/SasView/sasview/wiki/ContributorCampXV Registration is at: https://workshops.ill.fr/event/586/registrations/395/ We look forward to seeing many of you there Paul (for the SasView leadership team)

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SasView mailing lists moving to a new server this week
by Paul Butler via users 14 Jul '26

14 Jul '26

Dear SasView Users, Quick heads-up: sometime this week we'll be moving the SasView mailing lists (i.e., users, developers and help) onto a new server and upgrading from the old list software at the same time. The current server is well past its supported life and is being retired for security reasons. For almost all of you this will be invisible — the list addresses don't change and your mail keeps arriving as usual. A couple of things a few of you might notice: - Messages will now come from the new system, so they may look slightly different, and there is a small chance your mail provider might file the first one or two as spam. If that happens, just mark them "not spam." - If you'd set up a login to manage your own delivery settings, that login won't carry over — you'll need to register again on the new site (your list email address plus a new password). Everything else comes across automatically: all memberships and their delivery preferences, plus the full message archives — which are now searchable on the new system. Thanks for your patience during the move, and feel free to email help(a)sasview.org with any questions or concerns. Cheers Paul (for the SasView leadership team)

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Model building in sasview
by Harrison Laurent via users 02 Jul '26

02 Jul '26

Hello, I hope you are well. I am currently trying to build a reasonably complex model within sasview and have gone to the guide on how to manage this. I see in the documentation (SasView-6.1.3/sas/docs/user/qtgui/Perspectives/Fitting/fitting_help.html) that to achieve this one creates a 'simple' model combining two established models, then opens the model in the model editor. One can then add/multiply several different functions together by editing the text after 'load_model_info'. My question is how do I account for multiplying several summed models by a single other model, as brackets seemingly cannot be used. AKA how do I achieve the following sort of functions: (sphere + gaussian_peak + sphere)*user_defined_fractal_model ((sphere + gaussian_peak) + sphere)*user_defined_fractal_model ((sphere + sphere)*user_defined_fractal_model) + gaussian_peak Any insight you have would be extremely helpful. Thank you so much. All the best, Harrison Laurent

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help troubleshooting the low scattering intensity saxs data
by via users 06 Nov '25

06 Nov '25

Hi I need help from SASView experts. I started using it to fit my liposome saxs data just today for the first time. My scattering intensity data are very low ranging from 10^-3 to 10^-1. So, when I use lamellar_hg fit for my unilamellar popc vesicles I get ginormous chi squared values like 10^12. Please help me to improve my fitting. Thank you! Best Meko

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Upcoming SasView tutorial
by Paul Butler via users 10 Oct '25

10 Oct '25

Dear SasView Users, In anticipation of the upcoming SasView contributor camp to be held in Garching Nov 11-17 this year, the host institution requested a SasView tutorial be offered prior to the camp. This is taking the form of a two half day intermediate level SasView usage tutorial offered over zoom on Thursday and Friday October 23 and 24. The program is available at: https://indico.frm2.tum.de/event/594/ If you are interested in the program, registration is now open to anyone on a first come first served basis via the above link. Cheers Paul Butler, Annika Stellhorn, and Neelima Paul

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Bug Report – Unexpected Behavior of Polydispersity in SASview v6
by Abdoltajedini, Fatemeh via users 09 Oct '25

09 Oct '25

Dear SASview Team, I would like to report a possible bug I encountered in SASview v6 related to polydispersity. Description of the issue: When I add polydispersity to a model, the scattering curve changes far more dramatically than expected. Even small values (e.g., 0.05 on radius) cause the intensity and curve shape to shift disproportionately, which does not seem physically reasonable. Steps to reproduce: 1. Open SASview v6. 2. Load the [Core-Shell Cylinder]. 3. Fit the model without polydispersity – the curve looks reasonable. 4. Add a small polydispersity (e.g., 0.05 on radius). 5. The curve changes strongly in both shape and magnitude. Expected behavior: Polydispersity should broaden or smooth features of the scattering curve, but not cause large intensity changes or unrealistic distortions. Observed behavior: Even small polydispersity values produce a strong, unrealistic effect. Environment: * SASview version: 6.x * Operating system: Windows * Data used: experimental data Thank you for your help and for maintaining this valuable software. Best regards, Fatemeh

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