standard single tilt retainer

Resolution tests for the JEOL standard room temperature holder:

The standard JEOL room temperature holder is wide and has a limited tilt range (±20°) in our JEOL JEM 3200FS and ±XX° in the JEOL JEM 1400plus. On the other hand, it is very stable and produces high resolution images over this entire tilt range. Resolution tests were conducted using a holey carbon film that had both graphite fragments and "islands" of (poly)crystalline gold (the so-called "combined test specimen").

The images below were recorded using a microscope magnification of 300,000x (~377,000x at the CCD) and an exposure time of 1 second:

    untilted

untilted imagesub-image and FFT of full imageClick on the above image to see the Fourier transform of the full image and click here to see a higher magnification image of the gold

Both the spacing between the graphite layers (3.4 Å) and between the gold atoms (2.35 Å) are clearly resolved in the untilted image.

    +30°

tilted +30sub-image and FFT of full image

Click on the above image to see the Fourier transform of the full image.

    -30°

tilted -30sub-image and FFT of full image

Click on the above image to see the Fourier transform of the full image.

There is obviously some resolution loss in the direction perpendicular to the tilt axis (which runs across these images at ~35° counter-clockwise from horizontal), but it appears to affect resolution beyond the spacing between graphite layers (3.4 Å).

The field of view in the untilted image is ~160 nm and so there is also a significant defocus gradient across the tilted images (visible if one compares the upper left and lower right corners of each tilted image). This defocus gradient confounds the resolution apparent in the FFT of the full, tilted images. While tilted to -30°, an image at higher magnification (the 3200FS microscope reports 500,000x which corresponds to ~627,000x at the plane of the CCD) was also recorded. This additional image at -30° makes the field of view smaller (~98 nm) and also lessens the defocus gradient across the image:

tilted -30 and higher magnificationsub-image and FFT of full image

Click on the above image to see the Fourier transform of the full image.

The resolution along the tilt axis is still obviously significantly better, but the higher magnification image shows that there is some information perpendicular to the tilt axis at the resolution of the gold lattice (2.35 Å) when this holder is tilted to -30°.

All these images were recorded on 16-june-2009.