To truly optimize S/TEM imaging, EDX and EELS may require acquisition of different signals at different accelerating voltages. The rules may vary from sample to sample but, it is generally accepted that: 1) the best imaging is done at the highest possible accelerating voltage above which visible damage will occur, 2) EDX, especially when mapping, benefits from lower voltages with increased ionization cross-sections, thus yielding better signal-to-noise ratio maps for a given total dose, and 3) EELS works best at high voltages to avoid multiple scattering, which degrades the EELS signal with increasing sample thickness.
Unfortunately, acquisition at different accelerating voltages on the same sample without losing the region of interest—all during a single microscopy session—is not possible. At least, until now.
Imagine a Thermo Scientific Spectra 300 S/TEM:
- That can truly be operated at different voltages (all the voltages between 30 and 300 kV for which alignments were purchased) in a single microscopy session
- Where changing from an accelerating voltage to any other one takes about 5 minutes
- That can accommodate a radically different EDX concept with a 4.45 srad solid angle (4.04 srad solid angle with an analytical double tilt holder)
With the new Spectra Ultra S/TEM, the accelerating voltage becomes an adjustable parameter, just like probe current, and the massive Ultra-X EDX system enables chemical characterization of materials too beam-sensitive for conventional EDX analysis.
The Spectra Ultra aberration-corrected S/TEM offers an industry leading level of characterization capabilities for materials science and semiconductor applications at the highest resolution on a wide variety of samples.
Built on an ultra-stable foundation
The Spectra Ultra S/TEM is delivered on a platform designed to offer an unprecedented level of mechanical stability quality through passive and (optional) active vibration isolation.
Like the Thermo Scientific Spectra 200 S/TEM and Spectra 300 S/TEM, the system is housed in a fully redesigned enclosure with a built-in on-screen display for convenient specimen loading and removal. For the first time, full modularity and upgradeability can be offered between uncorrected and single-corrected configurations with variable heights, allowing maximum flexibility for different room configurations.