The SPECTRE S/TEM is a probe-corrected (scanning) transmission electron microscope (S/TEM) installed in Autumn 2024. It enables multimodal and correlative electron characterization, with capabilities for energy-dispersive x-ray spectroscopy (EDS), monochromated electron energy loss spectroscopy (EELS), and 4D-STEM diffraction characterization all within one microscope. The Ultra-X EDS detector will enable higher signal-to-noise EDS detection for faster and atomic-resolution chemical mapping. The UltiMono monochromator will provide better electron energy resolution (<30meV at 60kV), enabling characterization of optical and electronic phenomena with low loss electron energy loss spectroscopy.
Optics:
- High-brightness Schottky-field emission X-FEG electron source
- S-CORR probe corrector, which corrects coherent axial aberrations up to 4th order, as well as 5th order spherical aberration and six-fold astigmatism
- Operates at 60kV, 200kV, and 300kV, with the ability to switch kVs within a session
- UltiMono monochromator, enabling energy resolution down to <30meV at 60kV for electron energy loss spectroscopy
Stage:
- Piezo-enhanced CompuStage goniometer
- S-TWIN objective lens, giving a pole piece gap of ~5mm
- Compatible with many of our in situ holders for FEI microscopes
Detectors:
- Ultra-X energy-dispersive x-ray spectroscopy (EDS) detector, increasing EDS collection solid angle to >4.0 steradians, enabling higher signal-to-noise EDS detection. The Ultra-X detector is currently only compatible with a double-tilt holder and a tomography holder.
- Gatan Continuum K3-IS, a direct electron detector for electron energy loss spectroscopy (EELS) and energy-filtered imaging
- Ceta-S CMOS camera with speed enhancement, enabling up to 40 (full, 4k x 4k) frames per second, for imaging and diffraction
- Electron Microscope Pixelated Array Detector (EMPAD), a direct electron detector for 4D-STEM applications, with a dynamic range of 30 bit and maximum 1100 diffraction frames per second.
- To be installed in Spring 2025: Attolight cathodoluminescence mirror to collect cathodoluminescence spectroscopy
Experimental Modes:
- The microscope can be operated at 60kV, 200kV, or 300kV, and can be switched during a session
- Probe-corrected HR-STEM with 50pm resolution at 30pA beam current
- STEM-EDS for chemical mapping with a probe-corrected beam
- Electron energy loss spectroscopy (EELS) for both energy-filtered TEM and STEM-EELS
- Monochromated STEM-EELS for low loss electron energy loss spectroscopy and near edge core-loss bonding information
- TEM Lorentz mode and uncorrected STEM Lorentz
