GIF Tridiem

The GIF Tridiem is Gatan's 3rd generation of post-column energy filters. It combines 3rd-order spectrometer aberration correction with a multi-port, high-speed, high-resolution CCD sensor to yield a system that defines the new state-of-the-art in the capture of highly-detailed EELS and EFTEM data sets with maximum throughput. This new GIF, combined with the Gatan Microscopy Suite (GMS) software, is ideally suited for generating and working with the rich 3-dimensional data sets demanded by today's analytical electron microscopists, including EFTEM and EELS STEM spectrum images, EFTEM tilt and tomography series, and time series. GIF Tridiem makes such tri-dimensional EM readily accessible.

The key features of the GIF Tridiem system include:

• Large collection semi-angle for energy-filtered diffraction: 120 mRad, full azimuth (on TEMs with special GIF lens modes)
• Large field-of-view for energy-filtered TEM imaging and mapping: 20 um, diagonal (on TEMs with special GIF lens modes)
• Excellent isochromaticity over the entire EFTEM field-of-view: max variation no more than ±1 eV at 200 kV
• Very large searchable field-of-view in unfiltered TEM mode: > 200 um, diagonal (on TEMs with special GIF lens modes)
• Exclusive cinema mode readout for smooth, high-quality real-time viewing: > 10 frames/sec
• Rich EELS detail with each spectrum readout: > 2000 channels (e.g. capture 600 eV range at 0.3 eV/channel)
• High spectrum readout rate for STEM spectrum imaging: > 30 spectra/sec
• Complete system specification sheet available upon request (Gatan document 001.01010)

The GIF Tridiem is optimized for TEM beam energies from 200 to 300 keV and, as is true for all Gatan post-column energy filters, can be attached to the bottom flange of any modern TEM to form energy filtered images and diffraction patterns, as well as electron energy loss spectra. The post-column design provides maximum flexibility in the choice of electron beam source (W, LaB6, FEG, monochromator) and imaging optics (objective lens, correctors, TEM and STEM mode). Furthermore, Gatan's patented quadrupole optics ensure that spectra are always aligned with the detector, can be captured with a broad range of dispersions, and are optimally coupled to a rectangular area of the CCD detector to guarantee the absolute best dynamic range and sensitivity possible.

The electron optics of GIF Tridiem fully correct focusing aberrations of the prism through second order and also correct the most important third order prism aberration. This advance permits the use of a large 5 mm aperture at the entrance of the spectrometer, giving the GIF Tridiem a field of view that is 2.8 times the area of any previous GIF model. Despite the significant advance in spectrometer acceptance, distortions and resolution remain excellent across the entire field of view. Distortion is below 1.75%, chromaticity is less then 1.5 um/eV, and deviations from perfect isochromaticity are below 1.25 eV in magnitude over the entire image field. Using patented software algorithms, the performance of the GIF Tridiem can be checked and tuned fully automatically. When installed with the GIF integration packages available from most TEM manufacturers, GIF performance is further optimized by saving and recalling fine-tuned settings for each major mode and setting of the TEM imaging column.

The energy resolution of the GIF Tridiem in spectrum mode is unmatched by any other commercial system. For monochromated TEMs, GIF Tridiem models with even higher EELS performance are available for special order. Special consultation with Gatan is required before such orders can be accepted. The same holds true for applications at 400 keV and higher.

The GIF Tridiem comes standard with a 2K x 2K UltraScan 1000 FT (Frame Transfer) camera as its primary detector. This 4-port readout camera is 2 times faster than the 1K x 1K MSC of the GIF 2001 and 4 times faster than the 2K x 2K MSC of the GIF 2002 for imaging applications. The new detector is particularly advantageous for EELS data acquisition, offering truly live viewing of full spectra collected across the entire 2048-channel extent of the CCD. The GIF Tridiem sensor also offers an exclusive frame-transfer cinema mode that provides a high-quality live display for specimen searching and EFTEM setup. This same mode can be harnessed for rapid spectrum readout, 5-10 times faster than previous GIF models, which is especially beneficial for STEM spectrum imaging. The GIF Tridiem can be ordered with a choice of scintillators, a 'P' aimed at typical analytical TEM applications and a 'U' optimized for very low-dose imaging work. The use of the more sensitive U scintillator reduces the dynamic range of the system so please consider this option carefully.

Standard GMS software licenses for GIF operation, system tuning, and EFTEM/EELS data acquisition and analysis are included with each GIF Tridiem purchase. This includes drivers and basic GIF and camera operation software, AutoFilter tuning, basic EFTEM mapping and quantitative analysis of EELS spectra. As a bonus, the GIF Tridiem includes licenses for all GMS software modules required for EFTEM spectrum image data acquisition and analysis.

The basic instrument consists of a GIF Tridiem spectrometer with UltraScan 1000 FT detector, an entrance flange, pneumatic aperture assembly, magnetic prism, pre-slit quadrupole assembly, post slit multipole lens assembly, computer controlled slit, and all standard EELS/EFTEM software mentioned in the previous paragraph. Where required, a high performance computer workstation is supplied (See Recommended Computer worksheet for details). For full analytical STEM support, see the model 777 STEMPack product, which includes all the software and hardware required for STEM spectrum imaging.