[Neutron] Webinar 30 Jan. 2026 on wide angle neutron polarization analysis by Ross Stewart

[Karin Griewatsch]

Dear colleagues,

you are welcome to the KFN Neutron Webinar on


    Wide angle neutron polarization analysis time of flight
    spectroscopy: An Introduction


      Dr. Ross Stewart, ISIS
      Friday, *30 January 2026*, 11:00 - 12:00 CET

Zoom link: 
https://fz-juelich-de.zoom-x.de/j/61006517600?pwd=YiKR1xsor31wFo9EGRV7FNsiysGBBJ.1 
<https://fz-juelich-de.zoom-x.de/j/61006517600?pwd=YiKR1xsor31wFo9EGRV7FNsiysGBBJ.1>
Meeting ID: 610 0651 7600
Passcode: 983794

In recent years, polarised neutron spectroscopy on multi-detector 
spectrometers has become possible with the advent of wide-angle neutron 
spin analysers, either using polarizing supermirror arrays (e.g. D007 
(ILL), HYSPEC (SNS)) or 3He spin-filters (LET (ISIS), PASTIS (ILL)).  
Wide-angle neutron polarization analysis is particularly useful for 
studying materials with short-range or non-crystalline order. Most 
commonly, it has been employed to separate magnetic scattering in 
disordered magnetic materials from nuclear scattering using XYZ 
polarization analysis developed by Schärpf [1] in the mid-80s. At the 
same time, it was realised that polarized neutrons could also be 
employed in the study of soft-matter and biological materials due to 
their ability to distinguish single-particle dynamics (such as 
diffusion) from co-operative correlated motions via the separated 
coherent and incoherent neutron cross-sections in hydrogenous materials.

In this webinar, Ross Stewart will introduce the technique of uniaxial 
polarization analysis and its application to high resolution 
spectroscopy (QENS) studies using LET at ISIS, and on the proposed 
SHERPA spectrometer. Since neutron polarization experiments always come 
with a major flux and counting-rate penalty, he’ll discuss when (and 
when not) polarized neutrons are really necessary in QENS measurements, 
using examples from LEΤ. Future prospects for high-resolution magnetic 
spectroscopy with polarization analysis will also be discussed.

[1] O. Schärpf and H. Capellmann (1993). The XYZ‐Difference Method with 
Polarized Neutrons and the Separation of Coherent, Spin Incoherent, and 
Magnetic Scattering Cross Sections in a Multidetector. /Physica Status 
Solidi (A)/, /135/(2), 359–379. https://doi.org/10.1002/pssa.2211350204
<https://doi.org/10.1002/pssa.2211350204>
For the general background, see
https://www.oxfordneutronschool.org/2024/Lectures/Stewart_polarized%20neutrons.pdf
<https://www.oxfordneutronschool.org/2024/Lectures/Stewart_polarized%20neutrons.pdf>
R. M. Moon, T. Riste, and W. C. Koehler. Polarization Analysis of 
Thermal-Neutron Scattering. Phys. Rev. 181, 920 (1969)
https://journals.aps.org/pr/pdf/10.1103/PhysRev.181.920 
<https://journals.aps.org/pr/pdf/10.1103/PhysRev.181.920>

----

The lecture will be recorded, and there is information on data 
protection at
https://www.sni-portal.de/en/files/kfn-neutron-webinar-data-protection 
<https://www.sni-portal.de/en/files/kfn-neutron-webinar-data-protection>

On the website
https://www.sni-portal.de/en/user-committees/committee-research-with-neutrons/neutron-webinar 
<https://www.sni-portal.de/en/user-committees/committee-research-with-neutrons/neutron-webinar>
you will find announcements of upcoming lectures.

Kind regards,

Frank Schreiber and Thomas Gutberlet (Webinar organization)
Mirijam Zobel (KFN chair)
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