Intermediate Voltage Electron Microscopy (IVEM)-Tandem Facility (IVEM)
Building
IVEM
Primary Facility Type
Ion Irradiations
Secondary Facility Type
Post Irradiation Examination
Tertiary Facility Type
No Tertiary Facility Type Defined
Core Functions
The IVEM-Tandem facility is unique in the United States and is one of only five in the world. It is unique in its ability to image the changes in atomic structure and defect formation during irradiation at high magnification. Real Time observation of defect formation and evolution during irradiation. Well-controlled experimental conditions (constant specimen orientation and area, specimen temperature, ion type, ion energy, dose rate, dose, and applied strain). Refine and validate computer model simulations of irradiation defect states. High-dose ion damage is produced in hours, rather than the years such damage would require in a nuclear power plant, supporting studies of material response to high doses of particle (ion and neutron) irradiation. In situ ion irradiation does not produce any radioactivity in samples.
Unique Functions
Continuous recording of image with in situ specimen conditions of ion dose, temperature and strain.
Oil-free microscope vacuum of 5x10-8 torr enables transmission electron microscopy (TEM) of Fe samples at 600°C free of contamination and oxidation.
Sample stages for in situ irradiation include control of sample temperature to ±3C° over a range of 20 K to 900°C.
Mechanical stability of the sample at temperature and during irradiation allows a point resolution of 0.25 nm at 300 keV electron energy; with good sample quality, small defect clusters, dislocation loops, and voids/bubbles are resolvable down to a limit of 1-nm diameter.
Sample straining stage allows in situ experiments with samples under irradiation and stress at temperatures up to 600°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.
Hotwork Facilities
* Allow irradiation of neutron-irradiated specimens and nuclear fuel specimens (e.g. U, UO2, U-Mo, etc.)
- 5 mR/hr. @ 30 cm (~500 mR/hr. on contact)
- Uranium fuel and n-irradiated U fuel FIBbed samples
* A radiological facility, Irradiated Materials Laboratory (IML) located in the same building as the IVEM-Tandem can receive, handle, prepare and store radioactive samples. The IML has a dedicated Tenupol-5 for electro-polishing of radioactive TEM samples. Both the IVEM and IML are operated under ANL Nuclear Engineering Division
* Radioactive materials characterization using synchrotron X-rays is routinely carried out at the Advanced Photon Source.
Support Equipment
* Ex situ ion irradiation
- Triple-beam ion irradiation capability
(1) a 2 MeV Tandem accelerator
(2) a 500 keV ion implanter
(3) a low-energy ion gun
- Beam energy: 100 keV – 4 MeV heavy ions (e.g. Fe, Ni, Au, Si, etc.)
3 keV – 20 keV He
Radiological Limit
<5mr/hr @ 30cm
Materials Allowed
beta/gamma only
Sample Encapsulation
No Sample Encapsulation Defined
Atmosphere
* In situ heating/cooling (20 K - 1300 C):
- Double-tilt low-temperature stage (20 K - 295 K);
- Double-tilt high-temperature stage (20 - 900°C);
- Single-tilt high temperature stage (20 - 1300°C)
* In situ straining at the temperature:
- Single-tilt high-temperature straining stage (20 - 600°C);
- Single-tilt low-temperature straining stage (-196 - 100°C)
*In situ chemical environments: gas
- Environment cell holder (700°C)
