JEOL 6490 Low-Vacuum Scanning Electron Microscope

Location

JGB5.108

Overview

JEOL 6490LV SEM

 

Installed in 2008, our JEOL 6490LV SEM has secondary electron (SE), back-scattered electron (BSE), and energy-dispersive X-ray (EDS) detectors. The 6490 can operate in high- or low-vacuum modes, allowing the collection of sub-micron-scale imaging and X-ray compositional data without needing to coat or modify your sample! The EDS detector can be used to create qualitative and semi-quantitative elemental analysis of sub-micron point volumes, X-ray mapping over mm-scale single fields of view, and X-ray line-scans.

This SEM will be getting a major upgrade in Q1 2020! We will be installing a Gatan PanaCL detector, allowing the collection of cathodoluminescence signals; adding an Oxford Instruments Nordlys Nano EBSD detector; and upgrading the EDS detector to the far more powerful Oxford Instruments X-Max 50. The EBSD and EDS detectors will be configured for simultaneous collection, and both will run through Oxford Instrument’s very user-friendly Aztec software. After this upgrade, fully automated Large Area Mapping will become an option for the collection of SE, BSE, EBSD, EDS, and CL data!

 

Examples

EDS X-ray map of a garnet surrounded by deforming rock. 1024×1024 pixels, step size of 1.5 microns, dwell time 4 milliseconds.

 

Pottery shard used to create following images, on 75 mm stage.

Broken pottery edge, with brown-colored glaze on the right.BSE image, low vacuum mode.

Closeup of vesicle in pottery glaze. BSE image, low vacuum mode.

Closeup of pottery glaze crystallites. BSE image, low vacuum mode.

Contact between brown, crystallite-rich glaze and grey-colored glaze. BSE image, low vacuum mode.

Closeup of unglazed broken pottery surface. BSE image, low vacuum mode.

 

Vesicular basalt from Tillamook, Oregon, with zeolite micro-crystals growing in vesicles.

Wide angle view of edge of one of the zeolite-filled vesicle chambers. BSE image, low vacuum mode.

65x BSE view of zeolite on edge of vesicle. BSE image, low vacuum mode.

270x view of radiating crystallite pattern in zeolite. BSE image, low vacuum mode.

1,900x view of asbestiform zeolite crystals within the vesicle. BSE image, low vacuum mode.

Requirements of Samples

  • Because the SEM can operate in high- or low-vacuum modes, a conductive coating is not required for insulating samples. However, conductive samples (or those with a conductive coating) are preferable for optimal image acquisition and chemical analysis. Carbon coating is available in the DGS Electron Microbeam Laboratory.
  • Samples must be dry (water is the main concern, but some oil-saturated samples might also be unsuitable).

Sample Shape and Size

  • Typical samples are thin sections and materials < 1-cm diameter.
  • Four 1-cm diameter samples can be loaded into the SEM simultaneously.
  • Samples up to 5 cm in diameter may also be analyzed, with the warning that large samples pose the possibility of colliding with the detectors.
  • The stage can be tilted up to 55° from horizontal.

Standard-sized petrographic thin section holder/stage

Stage/Holder for standard SEM stubs. Can accommodate four 1″ or seven 0.25″ SEM stub mounts.

75mm stage