SAMPLE PREPARATION OUTLINE

There are 5 critical components of sample preparation for WiscSIMS analysis. Below are brief descriptions of each component with links to more detailed explanations.

Sample preparation components:

1. Sample flatness is essential.

Positive relief (peaks) should be <3 μm along the analytical traverse. Negative relief (e.g. bubbles in the epoxy) is not desirable, but is sometimes allowable.

2. Cast sample, standards, labels in an epoxy mount.

Glass thin-sections are also acceptable. Please contact WiscSIMS staff if you need to use other mounting methods.

Mount dimensions: 1 inch (~25 mm) diameter
Height: Less than 5mm is preferable, though a max thickness of 12 mm is allowed.

Analytical targets should be located within 8 mm of the center of the 1 inch mount and not show any surface relief or tilting.

A working standard must also be located within 8 mm of the center of each mount. Standards should be homogeneous, have known isotopic compositions, and match the mineralogy and major element composition of your sample. Please contact us if you do not have a suitable standard.

3. Polish epoxy mount.

Typically, a final grit of 1 μm is sufficient for diamond polishing, but a 0.25 μm finish (or better) is needed if samples will later be analyzed by EPMA.

4. Test flatness of epoxy mount.

Confirm that your sample mount is sufficiently polished by either optical microscope or white-light profilometer.

5. Image your sample before (and after) WiscSIMS analysis.

Sometimes this is best done after Au coating. At minimum, reflected light microscopy is recommended at low and high magnification. (The IMS-1280 reflected light microscope field of view is 500 μm.) Other types of imaging or scales of examination depend on the details of each sample and may include SEM, BSE, CL, EBSD, EPMA, or confocal laser fluorescent microscope.