TEM with in situ Ion Irradiation of Nuclear Materials: The IVEM-Tandem User Facility

Abstract

The IVEM-Tandem User Facility at the Argonne National Laboratory (ANL) is a world-leading research facility for in situ TEM study of ion irradiation damage and ion implantation near the atomic resolution. The IVEM-Tandem Facility interfaces a 500 kV ion implanter to a 300 kV Hitachi H-9000NAR transmission electron microscope. This combination allows experiments conducted with simultaneous ion irradiation/implantation and electron microscopy at temperatures ranging from 20 -1300 K. With superior electron brightness of a LaB6 filament, the H-9000 microscope is ideally suited for imaging irradiation-induced defects using diffraction contrast, a well-established technique in most cases superior to other imaging techniques. This permits effective real time observation of nanoscale defect formation and evolution during irradiation. Coupled with well-controlled irradiation conditions (constant specimen orientation and area, specimen temperature, ion type, ion energy, dose rate, dose, and applied strain), it provides key information on structure and defect dynamics of a material in an irradiation environment.The IVEM-Tandem Facility was commissioned in 1995 in the Materials Science Division of ANL, and was part of Argonne's Electron Microscopy Center, a National User Facility supported by the Department of Energy (DOE) Office of Science, Basic Energy Science. It was recently transitioned to the Nuclear Engineering Division of ANL, currently supported by the DOE Office of Nuclear Energy. The IVEM-Tandem serves more than 20 active user groups from universities, national laboratories, and nuclear industry in the U.S. and abroad, conducting research in areas of advanced alloys, accident tolerant materials and fuels, radiation-resistant fuel cladding, storage materials for spent fuels, and validation and verification of computer modeling and simulations. A facility upgrade is being considered to best address the critical problems of fission and fusion energy materials.TEM with in situ ion irradiation has made tremendous contributions to the understanding of defect production, accumulation and evolution under irradiation. Many of fundamental questions of radiation damage, e.g. single cascades, cascade -cascade, or cascade -subcascade interactions, defect production and annihilation rates of visible defect clusters, defect and dislocation interactions, etc. have been answered. A recent new direction is to predict neutron damage in bulk through in situ ion irradiation studies of thin films and coordinated computer modeling so that neutron irradiation effects can be evaluate by easily controlled ion irradiation experiments. For example, TEM with in situ ion irradiation experiments was conducted on molybdenum with 1 MeV Kr ions at the IVEM-Tandem Facility in combination with rate theory modeling. The in situ ion irradiation experiments were explicitly designed to compare with neutron irradiation data of the identical material reported in a previous study [1]. A spatially-dependent cluster dynamic model was developed to explicitly...

The Effect of Internal Free Surfaces on Void Swelling of Irradiated Pure Iron Containing Subsurface Trenches

“…Previously we mentioned the effects of irradiating thin foils where there are strong denuding effects from two surfaces and resulting two-dimensional heat transfer leading to temperature increases, requiring certain minimum thicknesses to approach bulk behavior in the center of the foil [25]. Experiments involving irradiation of a TEM specimen in an electron microscope at lower voltage coupled with an ion beam are increasingly common [29,30]. Such experiments require specimen thicknesses at~200 nm or thinner to be electron-transparent.…”

Ion beam irradiation of ABO4 compounds with the fergusonite, monazite, scheelite, and zircon structures

“…TEM specimens were prepared by lightly grinding a small amount of powder dispersed in ethanol and drop casted by a plastic pipette onto holey carbon coated copper TEM grids and dried in air. Ion irradiation experiments with 1.0 MeV Kr ions were carried out in situ at the IVEM‐Tandem User Facility at Argonne National Laboratory using a Hitachi TEM interfaced to a NEC ion accelerator 25 . All TEM observations were carried out using an accelerating potential of 300 kV.…”

“…Ion irradiation experiments with 1.0 MeV Kr ions were carried out in situ at the IVEM-Tandem User Facility at Argonne National Laboratory using a Hitachi TEM interfaced to a NEC ion accelerator. 25 All TEM observations were carried out using an accelerating potential of 300 kV. Ion irradiations were performed at temperature range of 50-1000 K with the electron beam of the TEM turned off, using a counting rate of 50 ion counts s −1 and a flux of 6.25 × 10 11 ions cm −2 s −1 within a beam of ~2 mm diameter.…”

Exploring Coupled Extreme Environments via In-situ Transmission Electron Microscopy

“…Challenges associated with constructing hardware, conducting experiments, and interpreting results make in-situ TEM a dynamic and active area of research. The range of capabilities for in-situ microscopy has grown prolifically in recent decades, permitting nanomechanical testing during chemical reactions [6,7], ion irradiation for radiation damage studies [8,9], ultraviolet-visible light illumination for photocatalysis [10], ultrafast high-resolution imaging for nanosecond-scale dynamic processes [11], and many others [12][13][14][15].…”