Metal Foam Found to Block X-Rays, Gamma, Neutron Radiation (Stephen)

The following comment was posted by Stephen on the Always Open thread.

There is an interesting article in Space daily about the use of metal foam to absorb radiation:

[From the article:

“Research from North Carolina State University shows that lightweight composite metal foams are effective at blocking X-rays, gamma rays and neutron radiation, and are capable of absorbing the energy of high impact collisions. The finding means the metal foams hold promise for use in nuclear safety, space exploration and medical technology applications.”]

It seems all kinds of radiatio n are affected including gamma, beta and neutrons but especially low energy gamma
It seems this material is more effective than solid material of the same weight at absorbing the radiation,
I wonder is it simply the increased volume that is having an effect or is there something about the structure that is increasing the absorption with these kind of materials. It seems to me from the article that the later is the case.

If so, I wonder about what mechanism is at work. Could it be that that the structure is some how increasing the probability of absorption by diffraction effects etc or is it something more to do with the way the material interacts with the radiation perhaps leading to evanescent waves on appropriately aligned surfaces, resonance effect and generation SSP etc.

Could the nano structure in LENR devices behave in the same way and if so could radiation in these devices be absorbed by this process?