After successful completion of the course, students are able to...

 understand how various soft matter systems can be analysed in particular using scattering techniques, including small angle scattering (SAS) and reflectometry.

Students will also be able to calculate relevant quantities related to scattering data (SLD, critical edge etc), allowing them to interpret reflectometry and SAS data analytically.

The theoretical background explained in the course will allow the students to understand how structure and form factors are derived and can be applied to predicting and the fitting of experimental data.

Upon completion the students will have had a step-by-step overview of the experimental design process for a scattering experiment and be able to make informed choices within a case study setting.

Students will also have a comprehension of the wide range of research questions for which scattering techniques can be applied to soft matter. These will include applications across diverse areas broader than the traditional discipline boundaries of Physics and Chemistry to also include examples from food science, engineering and pharmacology. Discussion of recent literature will also mean students will leave the course appreciating the current state of the art in the field.

1)    Overview of why we use neutrons and X-rays for soft matter research

1. Fundamental interaction with elements and scattering lengths
2. Length scales and structures
3. Reciprocal space

2)    Diffraction to structure factor determination using example of liquid crystals

1. Lattice determination
2. Fourier transforms (not examined)
3. Ewald sphere construction
4. Bragg peak interpretation (Scherrer broadening and position)

3)    Small angle scattering

1. Approximations (Guinier, Porod, fractals)
2. Absolute intensity and general scattering formula
3. Form and structure factors
4. Contrast matching
5. Fitting methods

4)    Reflectometry

1. Ambiguity of some SLD profiles and how to break it
2. Kinematic vs optical formalism (matrix method)
3. Analytical interpretation (critical edge, fringes, Bragg peaks)
4. Fitting methods

5)    Large scale facilities

1. Different neutron and x-ray sources (comparison to lab sources)
2. Experimental design
3. Access process

6)    Examples from the current literature

1. Dispersions, bilayers etc
2. Complementary techniques

7)    Case study (homework and exam)

Teaching will be a mixture of input and discussion on the basis of recent scientific discoveries and publications. Scientific publications will be available online for self-studies, and will be discussed in the lectures individually.

This is a good complementary/follow-up lecture for: 141.242 Neutron and X-ray Diffraction and 134.230 Colloid and Interface Physics, but will also be in enough detail to follow without.

Book recommendations:

D. S. Sivia Elementary Scattering Theory For X-ray and Neutron Users, OUP, Oxford, 2011.

J. Als-Nielsen and D. McMorrow, Elements of Modern X-ray Physics, John Wiley & Sons Ltd, Chichester, 2^nd edn., 2011

B. Hammouda, Probing Nanoscale Structures – the SANS toolbox https://www.ncnr.nist.gov/staff/hammouda/the_SANS_toolbox.pdf

Written (take home case study material to prepare a short ~2 page report) and oral feedback/discussion of the prepared material.

It is not a prerequisite but it is recommended that students have already completed the following classes (or an equivalent) in order to follow the lecture in every detail:

153.075 Chemistry for TPH

134.120 Grundlagen der Physik III (diffraction parts)