Information on SIMS primary image shift

Some of the SIMS ion images were not aligned with respect to the previous or next image in the same analysis. This was caused by sample movement or accidentaly moving the CCD array. To compensate this, the images were sometimes manually shift-corrected.

The raw datafile contains essentially unshifted images but a field in the image header containing the shift value. All images displayed on the data pages of this archive are shift-corrected.

Shift correction affects semi-quantitative impactor classification and origin determination because sometimes images containing only spots had to be realigned.

Klaus G. Paul, 7-22-1994