Speaker
Description
The coherent scattering length $ b_c $ is a fundamental property for many neutron techniques, but have to be determined for each nuclide individually. Although this has carefully been done over decades and results were summarized in established standard tables, some $ b_c $ values have large experimental uncertainties, including possible systematic errors, or have not been determined experimentally at all.
We therefore decided to take advantage of modern neutron powder diffraction (NPD) and to redetermine bound coherent scattering lengths bc of important isotopes, in particular those often used for isotopic substitution, e.g. to obtain scattering-length contrast or to avoid strong neutron absorption. Although other techniques such as neutron interferometry may be more precise under ideal conditions, we have found in a systematic study that neutron powder Bragg diffraction is a practical, powerful, and reliable technique that can achieve uncertainty levels of 1% or less and is even applicable on sub-gram samples with modern high-flux instrumentation.
Among others, we will present updated $ b_c $ values for all seven natural Nd isotopes, for $ ^{141}$Pr, and for $ ^{147/148/150/152}$Sm, of which some have never been determined experimentally before, as well as carefully redetermined values for $ ^{6/7/nat}$Li being of particular interest for modern battery research.
