With respect to traditional neutron optical techniques?

Yes, in neutron optics.

Don't think so - rather more precise.

Dear Alexandra,

Thank you for your interest and for the sent paper.

But I need more...

I am interested in a new exp/th way of neutron – electron scattering length, bne. First this question was analyzed by E. Fermi in 1947. The main idea of the issue is that the neutron has an internal structure and according with the old Yukawa theory on nuclear forces the neutron is a system of proton + negative pion (the pions cloud). This fact gives reason to measure the electric dipolar moment of neutron and the n-e scattering length.

It is obviously that the electric dipolar moment of neutron has a very small value and deviation of neutron beams in intense electric fields have not given a certain final results and the conclusion was that neutron polarization and scattering length can be evidenced in the vicinity of nuclei. First experiment was proposed in an experimental setup which until nowadays is still respected with some modifications and improvements.

The neutron – electron scattering length is of order of -10-3 fm and therefore it is very difficult to measure effects caused by such small value. Taking into account that the interaction between neutron and electron has a small asymmetry in the center of mass system it is possible to evidence the presence of electric dipolar moment of neutron in the interaction of slow neutrons with noble gases (noble gases – to avoid magnetic interaction between neutrons and electrons).

In the present the experiments have evidenced scattering length with values higher and lower than -1.4 fm. According to Yu. A. Alexandrov (Oxford, 1992) the value lower than -1.4 fm contradicts the Yukawa theory and consequently the questions related to this issue are of actual interest. The carried out measurements are based on Fermi experimental setup and also need for a lot of corrections which affect the evaluations. From here the question that arises: it is possible a new experimental setup for n-e scattering length and neutron polarizability measurements?

One more reference

One more ref

One more ref

Uhm, I'm not so familiar with optical techniques - heard about derivations of n's electric polarizability and bs from heavy-atom n cross-sections over epithermal n energies (which is much more routine to me) but cannot say what kind of improvement this can represent.

I see here that the Dubna group is one of the most active in the field.