Microscopes and Facilities
Staff
Becoming an NCEM User

NCEM Fellowship
Workshops and Seminars
Assistance and Collaboration

Publications
New Research
Gallery
Microscopy Links

ARM

The Atomic Resolution Microscope has been specifically designed for performance in the high resolution imaging mode with a point-to-point resolution of 1.5Å and an information limit of about 1.4Å. The combination of high resolution with high angle (±40°) biaxial specimen tilting capabilities is unmatched by any conventional high resolution microscopes. By incorporating a microprocessor-controlled (z)-variable goniometer, the microscope operates with a constant Cs.lambda product over its entire voltage range (400kV to 800kV). Images at magnifications above 200,000 times can be viewed using a Gatan image intensifier, recorded on film or videotape, or Fourier-transformed on-line for easy and accurate microscope alignment. Specifications for the ARM at its optimum operating conditions are given below.

 For updates or questions, contact Christian Kisielowski or ChengYu Song.

Specifications
Accel. Voltage:	400-800 kV
Spherical Aberration Cs:	1.25- 2.0 mm
Chromatic Aberration Cc:	3.0mm
Point Resolution	1.5Å
Spread of focus	~120Å
Scherzer defocus	-525Å
Tilt range	±40/±40°

	ARM micrograph of SiC in{1-100}orientation showing 1.5Å resolution given by the narrow, horizontal dot spacing.
	Atomic resolution image of Sigma 99 tilt grain boundary in Al.
	High resolution images of a GaAs island seen at -45° and +45° tilt.
	Diffractograms (one-dimensional (above) and two-dimensional (center)) computed out to 1.0A for the ARM operating at 800keV and -525A defocus show how transfer extends to beyond 1.5A. One-dimensional contrast transfer function (CTF) shows crossover at 1.4A at -525A defocus.

Top