Radiation damage in nanostructured materials

The "textbook" phonon mean free path of heat carrying phonons in silicon at room temperature is ∼40  nm. However, a large contribution to the thermal conductivity comes from low-frequency phonons with much longer mean free paths. We present a simple experiment demonstrating that room-temperature thermal transport in Si significantly deviates from the diffusion model already at micron distances. Absorption of crossed laser pulses in a freestanding silicon membrane sets up a sinusoidal temperature profile that is monitored via diffraction of a probe laser beam. By changing the period of the thermal grating we vary the heat transport distance within the range ∼1-10  μm. At small distances, we observe a reduction in the effective thermal conductivity indicating a transition from the diffusive to the ballistic transport regime for the low-frequency part of the phonon spectrum.

Direct Measurement of Room-Temperature Nondiffusive Thermal Transport Over Micron Distances in a Silicon Membrane

Materials Science and Engineering at ORNL

Effects of compositional complexity on the ion-irradiation induced swelling and hardening in Ni-containing equiatomic alloys

Opportunities and limitations for ion beams in radiation effects studies: Bridging critical gaps between charged particle and neutron irradiations

Emulation of reactor irradiation damage using ion beams

Void swelling and microstructure evolution at very high damage level in self-ion irradiated ferritic-martensitic steels

Effect of pre-implanted helium on void swelling evolution in self-ion irradiated HT9

Effect of irradiation mode on the microstructure of self-ion irradiated ferritic-martensitic alloys

The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels

E. Getto

Papers

Emulation of reactor irradiation damage using ion beams

Void swelling and microstructure evolution at very high damage level in self-ion irradiated ferritic-martensitic steels

Effect of pre-implanted helium on void swelling evolution in self-ion irradiated HT9

Effect of irradiation mode on the microstructure of self-ion irradiated ferritic-martensitic alloys

The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels