FEI Tecnai Osiris

The Osiris is a state-of-the-art analytical instrument designed for easy TEM imaging and fast chemical mapping in scanning transmission electron microscope (STEM) configuration using energy dispersive X-ray and electron energy loss spectroscopies (EDX and EELS). Its primary beam energy is 200keV, but a lower energy of 80 keV has been commissioned for carbonaceous nanostructures, e.g. nanotubes, and materials sensitive to knock-on damage.

It has an extreme Schottky gun (FEI 'XFEG' gun), which is a field-assisted thermionic emitter (measured brightness = 2.6 x 10¹³ A/m² sr) providing high currents (up to 50nA) into moderately small, nanometre-sized probes. Specimens are mounted in side-entry holders with the following capabilities: low-background beryllium double-tilt, standard Be double-tilt, single-tilt (+/-35 degrees), tomography single-tilt (+/-80 degrees), tomography tilt-rotate, tomography on-axis, low temperature (liquid nitrogen) beryllium double-tilt, plus others.

TEM imaging is accommodated with a Gatan UltraScan1000XP (2048 by 2048 pixel) camera with high-speed upgrade. STEM can be performed using FEIs Tecnai Imaging and Analysis (TIA) or Gatan DigiScan II system. Four STEM detectors (HAADF, DF4, DF2 and BF) allow angular integration over a wide range of collection angles and are compatible with the EEL spectrometer. EDX detectors are FEIs Super-X system employing 4 Bruker silicon drift detectors (SDD) for high collection efficiency (>0.9 sr solid angle) and high count rates (>250 kcps). EELS is performed using Gatan's Enfinium ER 977 spectrometer with electrostatic shuttering and fast Voltage Scan Module for Dual EELS (sequential low-loss and high-loss spectrum acquisition) and RangeEELS.

Finally, tomography, through-focal-series and microprobe STEM (STEM-CCD imaging) allows three-dimensional reconstruction, exit-wave reconstruction and strain mapping capability respectively.