Skin effect in neutron transport theory

Abstract

We identify a neutron-flux "skin effect" in the context of neutron transport theory. The skin effect, which emerges as a boundary layer at material interfaces, plays a critical role in a correct description of transport phenomena. A correct accounting of the boundary-layer structure helps bypass computational difficulties reported in the literature over the last several decades, and should lead to efficient numerical methods for neutron transport in two and three dimensions.

Parallel inverse-problem solver for time-domain optical tomography with perfect parallel scaling

“…cients for the spine, the spinal chord, and the trachea will remain fixed in the reconstruction process (in accordance with the values provided in [37]), since tumoral angiogenesis is only expected to exist in the soft tissue. Additionally, we restrict the presence of tumor inclusions to regions slightly away from the neck boundary, so as to avoid the error amplification associated with the existence of exponential boundary layers [39] (a full treatment of such nearboundary imaging configurations is left for future work). Accordingly, the value of the absorption coefficient in the proximity of the boundary is set to the background tissue value a(x) = a b (x) at all points closer than 0.5cm from the boundary.…”