Listening to Radiation Damage In Situ: Passive and Active Acoustic Techniques

Abstract

Knowing when, why, and how materials evolve, degrade, or fail in radiation environments is pivotal to a wide range of fields from semiconductor processing to advanced nuclear reactor design. A variety of methods, including optical and electron microscopy, mechanical testing, and thermal techniques, have been used in the past to successfully monitor the microstructural and property evolution of materials exposed to extreme radiation environments. Acoustic techniques have also been used in the past for this purpose, although most methodologies have not achieved widespread adoption. However, with an increasing desire to understand microstructure and property evolution in situ, acoustic methods provide a promising pathway to uncover information not accessible to more traditional characterization techniques. This work highlights how two different classes of acoustic techniques may be used to monitor material evolution during in situ ion beam irradiation. The passive listening technique of acoustic emission is demonstrated on two model systems, quartz and palladium, and shown to be a useful tool in identifying the onset of damage events such as microcracking. An active acoustic technique in the form of transient grating spectroscopy is used to indirectly monitor the formation of small defect clusters in copper irradiated with self-ions at high temperature through the evolution of surface acoustic wave speeds. These studies together demonstrate the large potential for using acoustic techniques as in situ diagnostics. Such tools could be used to optimize ion beam processing techniques or identify modes and kinetics of materials degradation in extreme radiation environments.

The In Situ Ion Irradiation Toolbox: Time-Resolved Structure and Property Measurements

“…112,113 Contactbased ultrasonic techniques have also been deployed in ion beam and other radiation environments to observe changes in elasticity and detect irradiationinduced events through acoustic emission, but applications of these methods have been narrow so far. 114,115 Before discussing each of these classes of experiments in turn, we note that by targeting performance characteristics directly, these methods all capture the integrated effects of defect accumulation and microstructure evolution across all defect sizes from the nanoscale to the microscale. While methods such as in situ microscopy must by nature be targeted at one primary length scale of interest (SEM vs. TEM for example), methods which capture material properties directly will integrate the effects of defects at all scales as long as the representative sampling volume remains larger than the scale of individual defects.…”

“…However, to date, the most expansive use of in situ laser-based thermophysical property measurement techniques has come from the application of transient grating spectroscopy (TGS). 115,116,[119][120][121][122] All of these photothermal and photoacoustic methods fall into the category of pump-probe techniques where some form of laser excitation is provided to induce a response in the material in question. Following excitation, a probing laser detects the material response through physical displacement, the thermoreflectance effect, or some combination of both.…”

Polymeric Membranes for O2/N2 Separation

“…However, a nonselective resistance layer is formed when high irradiation is applied and decreases both in selectivity and permeability [70]. Generally, ion beam techniques include ion irradiation, ion implantation, and focus ion beam where the ion irradiation and the ion implantation involve ex-situ and alternatively, the focus ion beam involve in-situ modification [71]. They are all pure physical processes as none of them introduces any foreign species into the targeted polymeric membrane.…”

“…Generally, ethyl cellulose (EC), linear polyimide (LPI), hyperbranched polyimide (HBPI) and poly 2,6-dimethyl-1,4-phenylene oxide, and magnetic nanoparticles like ferroferric oxide (Fe2O3 and Fe3O4) or a permanent magnet like neodymium, praseodymium, ferrite, etc. are used to fabricate a smart polymer magnetic membrane [70][71][72][73]. The permeability of O2 highly depends on the magnetic field induction.…”

Using In Situ TEM Helium Implantation and Annealing to Study Cavity Nucleation and Growth

“…Several in situ characterization techniques have been employed to characterize gas cavity behavior as a function of dose, time, or temperature, including elastic recoil detection, 24 positron annihilation spectroscopy, 25 TEM, 26,27 transient grating spectroscopy, 28,29 and acoustic emission. 29 We demonstrate the utility of in situ TEM ion implantation and annealing experiments for providing in situ time-dependent data on gas stabilized cavity evolution and growth in extreme environments and suggest how those data can motivate and aid validation of models that provide a mechanistic explanation for macroscopic physical phenomena. 30 In situ TEM He implantation has previously been performed on several pure metals.…”