Transmission Electron Microscopy Capabilities
The IVEM interfaces with an ion beamline incident from above at 30° to the electron beam, allowing in situ irradiations during observation under controlled sample and diffracting conditions.
- Hitachi-9000 with side-entry sample stages, LaB6 filament
- Range of electron energies, 100-300 keV
- A range of total electron currents directly measured with Faraday cup stage
- Point resolution, 0.25 nm at 300 keV
- Excellent mechanical stability of sample at elevated temperatures during in situ irradiation, resolving defects to 1 nm
- Oil-free vacuum of 5x10-8 Torr at sample
- GATAN OneView digital camera with full resolution images of 4kx4k pixels and 16 bit dynamic range
- In situ movies in two modes:
- ANL system with data bar, 1Kx1K and 10 frames per second (fps).
- GATAN in situ mode (without data bar) up to 200 fps at 1Kx1K resolution with “look back” feature.
- Data file sizes:
- Single image at full resolution, 66 MB.
- ANL movie with data bar, 2 GB in 10 minutes.
- GATAN in situ movie at 1Kx1K resolution and 200 fps, 100 GB per minute.
Computer Vision Assisted Video Analysis
- Automated analysis of irradiation-induced voids by a semantic segmentation model.
- Individual voids can be identified and measured frame-by-frame to reveal the dynamics of microstructural evolution in materials under irradiation.
Sample Stages for in situ TEM
- High temperature (20-850°C, ±3°C), double tilt (±40°, ±20°). No epoxy above 300°C, no Cu grids above 600°C.
- High temperature (20-1100°C), single tilt (±40°). Same restrictions as above.
- Low temperature (20-300°K), double tilt (±40°, ±20°).
- Triple axes, double tilt (±40°, ±10°) rotate (180°), room temperature.
- Straining, high temperature (20-400°C), single tilt (±40°). No epoxy above 300°C.
- Straining, low temperature (100-400°K), single tilt (±40°). With permission.
- Environmental cell TEM holder (700°C) with an oxidizing reaction chamber (300°C), single tilt (±40°).
In Situ Capabilities
- Continuous recording of image with in situ specimen conditions of ion dose, temperature and strain.
- Sample stages for in situ irradiation include control of sample temperature to ±3C° over a range of 20 K to 1100°C.
- Sample straining stage allows in situ experiments with samples under irradiation and stress at temperatures up to 400°C.
- Three-rotation-axes sample stage (double-tilt rotate) allows a relatively easy tomography measurement (±40° tilting) for imaging of defects and microstructure in 3D maintaining constant diffraction conditions.
Irradiation defects in Mo in 3D
Movie of interstitial dislocation loops formed in Mo by 1 MeV Kr ion irradiation at 80°C, rotating in 3D and produced by reconstruction of tomographic data while maintaining constant diffraction condition.
Meimei Li, M.A. Kirk, P.M. Baldo, Donghua Xu, and B. D. Wirth, “Study of Defect Evolution by TEM with in situ Ion Irradiation and Coordinated Modelling,” Phil Mag. 92 (2012) 2048.