Small Matters Spring 2025
03 Sep 2025
Welcome to Small Matters, the newsletter of the ISIS Small-Angle Neutron Scattering (SANS) group. This is our first issue for 2025, and since our last newsletter, lots has happened here at ISIS, on the SANS instruments, and in our group. We have news about our recent records for lowest temperatures and smallest sample volumes studied on ISIS SANS instruments. Also, we have two deadlines coming up in the next few months.
Along with Diamond Light Source and the ILL, we are hosting a UK SAS User Meeting on 16-18 June 2025 at the RAL campus. This will be of interest to both SAXS and SANS users and will cover the many different areas that these techniques are used. More information can be found below, and you can register now.
We are currently open for new proposals. The ISIS round opened on 3 March 2025, and you can submit proposals until the deadline of 16 April 2025 at 17:00 UK.
If you have any questions, comments or wish to contribute then please contact one of the team. You can find more information about the us on our web pages or contact us by email at SANSgroup@stfc.ac.uk.
Instrument updates
The three TS2 SANS instruments (Larmor, SANS2D, and Zoom) continue to run a full user programme, using a range of sample environments and SANS variants. LoQ is still operational and is predominantly used for rapid measurements and operational tests.
Larmor
The ISIS SANS Group together with the ISIS cryogenics team has made significant progress in enhancing our sample environment capabilities. On Larmor, we achieved the low-temperature record on an ISIS SANS instrument reaching 35mK above absolute zero. This achievement enables ultra-low-temperature research investigating quantum phase transitions that are otherwise covered by thermal fluctuations, like quantum spin liquids and heavy fermion superconductivity. Dilution refrigerators are a common sight on muon instruments, inelastic spectrometers and diffractometers to study quantum states in materials. Now, thanks to the effort of the ISIS cryogenics team this ultra-low temperature capability is available for SANS and puts the sample environment suite on par with other neutron research facilities.
The Larmor SESANS setup continues to show great stability, returning to nearly the same tune point even after being disassembled between cycles. The count rate possible with SESANS has dramatically increased (nearly 100×) with a new scintillator detector provided by the ISIS Detectors Group. You can read more about this in a recent publication. This brings the performance of the instrument up to the levels originally anticipated for the technique but which had been limited by detector saturation effects. Excitingly there may still be room for further improvement with the potential for another factor of 2 if the detector technology can be improved further.
SANS2D
SANS2D continues to push the sample environment envelope. Recently, Prof Yujun Feng (Sichuan University) and co-workers studied the formation of a bicontinuous microemulsion in a microfluidic chip they had fabricated. Though this was not the first such device to have been used on SANS2D, the experiment was notable for scattering from the smallest sample volume yet studied on the instrument: just 1.8 mm3. The finely collimated beam passed through a channel 500 micron wide by 500 micron deep. The image below shows the chip mounted against a quartz glass heating plate that provided the temperature control.
Zoom
In collaboration with Bana Shriky and Tim Gough from Bradford University, a variety of shear sample environments were deployed on Zoom, including a mixed flow syringe device for studying how hydrogel structures develop under mixed shear and extensional flow as temperature is increased following formulation injection: a 1,2 plane shear rheometer (adapted and improved from a NIST design) and a cross-slot extensional flow device. The image below shows the 1,2 plane shear rheometer with temperature control through a water bath.
LoQ
The TRAM (Target, Reflector and Moderator) assembly on Target Station 1 was recently refurbished, and after a period of delays due to vacuum leaks and additional testing, the whole of TS1 is currently operational again. The new hydrogen moderator has a water pre-moderator placed between it and the target in a similar way to the TS2 design. This boosts the long wavelength performance at the expense of a modest relaxation in the spectral width. Preliminary analyses of the data taken suggest that the new moderator and redesigned neutron target are now delivering a factor ~2 increase in neutron flux across the LoQ wavelength band compared to the pre-refurbishment baseline. As long-time LoQ users will appreciate, this is obviously a significant and very welcome development.
Changes in the materials in the new TRAM assembly have also reduced the depth of dips in the spectrum, and slightly shifted the spectral peak to longer wavelengths. A practical benefit of the latter, aided by the improved flux, is that the LoQ chopper can be rephased to shift its window to slightly longer wavelengths than before, thereby improving low-Q performance. Preliminary indications are that a minimum Q around 0.0055 Å-1 will be realisable compared to ~0.007 Å-1 before, albeit with a small reduction in the maximum Q from ~1.4 Å-1 to ~1.2 Å-1. The old configuration will remain available for those that require it.
Software Updates
There have been a series of underlying technology updates to the IDAaaS platform that may impact how you use it. This is due to an upgrade of the system from CentOS7 to Rocky 8 Linux and implementation of the ISIS Instrument Data Cache, which is in alignment with ISIS Data Policy.
The current version of Mantid was launched in February 2025 (to version 6.12), and all users of the program are encouraged to update. For the full list of changes, make sure to read the Release Notes.
For SANS users it is now possible to perform a ‘scaled background reduction’ from within the SANS Interface Reduction Table, whereby only some fraction of the Can background is subtracted. For more information, ask your Local Contact. Work is also currently underway to provide Polarised SANS users with a more holistic data reduction experience, and the new additions to enable this are available in version 6.12.
Another change being implemented for all users of Mantid concerns the Error Reporter, the window that pops up when something goes badly wrong. Starting with version 6.9.0, it is now mandatory to provide an email address in order to submit a bug report. This change has primarily been made to enhance the value of bug reports to the Development Team, who may now contact you for further clarification, but in the future, it could also be used to provide, for example, automated updates on the progress of your bug report, strengthening the software-stakeholder feedback loop and improving everyone's user experience. So, please, do help us to help you by submitting useful bug reports.
A major new version of SasView (6.0.0) was released in October 2024, debuting a whole range of changes. All users of the program are encouraged to update. For the full list of changes, make sure to read the Release Notes. The Development team has just released a minor update (version 6.0.1) and a new feature release is planned in June (version 6.1.0).
Please report any issues when installing/using the program to the usual help@sasview.org or, if you prefer (and have a GitHub account), complete a bug report.
Whenever reporting back, please make it clear which version of SasView you are running, which platform you are using (Windows, Mac, Linux), and also your specific operating system version (which seems to be increasingly important with Macs). Equally, it would also be great to hear if you are enjoying the program and finding it useful.
Recently, the Development Team have been asked several times how the user base can contribute. SasView is a community development effort, and all contributions are welcome. Some of the low hanging fruit identified in these discussions were in documentation and helping to test new releases. But, of course, Python experts are equally welcome. So, if you can spare even a little of your time, then please get in touch.
In this vein, SasView has started staging Contributor Camps to help people get involved with project, and the next one is planned for November 2025 at TU Munich; details will appear soon on the SasView website. There will also be a Magnetic SAS data analysis workshop held alongside ICNS 2025. As new opportuniteis are announced, you can find more about future events on the SasView website.
As a reminder, we do offer online guidance and tutorials to getting the most from your data reduction and analysis.
Staff News
Lauren Matthews and Steven Parnell recently started as Instrument Scientists in the SANS Group.
Lauren Matthews
Instrument scientist
Steven Parnell
Instrument scientist
Before starting at ISIS, Lauren was beamline scientist on the ID02 time-resolved USAXS beamline at the ESRF in Grenoble. Outside of beamline duties, Lauren has an interest in poking soft matter and colloidal systems with various forms of radiation, to probe structural details in gels, microemulsions, and lipid systems. In particular, she is interested in this combined with a rheometer, or doing stopped-flow rapid mixing experiments. Outside of science, she likes winning board games (rarely happens), binge watching Netflix series, and running after her cat. Before starting at ISIS, Steven was most recently a lecturer at TU Delft. Steven is a long-time ISIS user and will bring this expertise to the Larmor instrument and development of polarised neutron and spin-echo techniques.
Stephen King
Stephen King (below far right) retired from ISIS in December 2024. Over the years, Steve made essential contributions to the work of the ISIS SANS group and the SAS community. His work on the development and operation of the LOQ instrument with Richard Heenan and the provision of software to support users have formed the bedrock on which the current ISIS SANS program has been built. His support for standards and collaborative software projects has been of benefit to the whole SAS community, making all our lives easier. We were able to celebrate this in December 2024 before his last day. We want to thank Steve for everything he achieved during his time at ISIS. He will be greatly missed.
Events
The inaugural UK Small Angle Scattering Users Meeting will be held at the Rutherford Appleton Laboratory on 16-18 June 2025. This event will showcase the diverse spectrum of activities in small angle scattering and will have a broad scientific focus with plenary and invited speakers, including Annela Seddon (Bristol, UK) and Peter Beaucage and Tyler Martin (NIST, US), setting the scene for sessions covering areas of soft matter, magnetism, polymers, energy materials, structural biology and biophysics.
The event will be focused on the science from UK users of the ILL, Diamond and ISIS facilities. In addition, the facilities will provide updates on recent developments and future plans. In the evenings Diamond House will host poster sessions, and we encourage all members of the community to attend. We would value your attendance in person, but due to the international nature of the event, we will also be providing hybrid facilities. A limited amount of funding will be available for the provision of accommodation only which will be allocated on a first come first serve basis.
To register and to provide an abstract for a presentation and/or poster please access the form.
Applications are open for the ISIS Data Clinic on 20 June 2025. The Data Clinic will provide ISIS users with an opportunity to receive support and feedback on complex analysis challenges from software engineers, instrument scientists and fellow users.
Applications are open until 20 May 2025. Decisions will be sent as soon as possible, but the exact timing will depend on the number and type of applications. There will be support for travel and subsistence costs for users from UK institutions.